1st Bimonthly - Modules 1-5(1)

7/28/2019 1st Bimonthly - Modules 1-5(1)

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Correlate: Adult Learning and Memory

Instructional Objectives:At the end of this module the student is expected to:

1. Identify definitions/descriptions of teaching and learning.2. Identify the criteria for good teaching.3. Identify the criteria for good learning.4. Identify the definition/description of pedagogy and andragogy.5. Identify the factors that facilitate adult learning.6. Identify the principles of adult learning.7. Identify descriptions of the various steps involved in the inductive method of teaching.8. Identify descriptions of each phase of learning.9. Identify the learning outcomes proposed by Gagne.10. Identify descriptions of the different stages of memory.11. Identify descriptions of the two forms of memory. Identify their sites of integration.12. Identify the classification of memory. Identify characteristics of each.13. Identify the various hormones, neuropeptides and drugs that affect learning and memory.14. Identify descriptions of the 3 states of memory.15. Identify the various ways of improving memory.16. Identify descriptions of the 3 theories of forgetting.17. Identify descriptions of the different types of amnesia.

Definitions:

Teaching refers to all those interactions that take place between the teacher and the students in order to bring aboutexpected changes in behavior of the students. Such expected change in behavior, when it occurs, is called learning .

Criteria for Good TeachingIn order for teaching to be effective, the following criteria are suggested:

1. Teaching should be based on the psychology of learning.2. Teaching should be well planned.3. The teacher should have aims or goals to be accomplished.4. Teaching should be made psychological rather than logical.5. Teaching should provide varied experiences or situations that will ensure understanding.6. Teaching should utilize the primary laws of learning: readiness, exercise and effect.7. The process of teaching should utilize past experiences of students.8. The learner should be stimulated to think and to reason.9. Teaching should be governed by democratic principle.10. There should be humor that evokes laughter in the classroom.

11. Evaluation should be made an integral part of learning process.

Criteria for Good Learning:Learning is said to be good, if the following criteria are present:

1. It utilizes the theory of self-activity.2. The learner has a motive for learning.3. It utilizes the laws of learning.4. It provides experiences or situations that will ensure understanding.5. It utilizes the principle of transfer.6. It has provision for individual differences.7. It utilizes the principle of integration.8. It utilizes group process.9. The process involves utilization of many senses.10. It is governed by democratic process.11. It has provision for evaluation.12. Both the faculty member and the students are happy.

Pedagogy and AdragogyPedagogy refers to the art and science of teaching children to learn. Androgogy in turn refers to the art and science of

teaching adults to learn.

Although children and adults learn continuously, adults have preferences about how they learn. Some adults relyheavily on feeling-based judgments and learn best form specific examples, from involvement and discussions. Such adult learnersare called concrete experiencers . Some adults have a tentative, impartial and reflective approach to learning and are calledreflective observers. Other adults have an analytical and conceptual approach, using logical thinking and rational evaluation, andare called abstract conceptualizers . Lastly, some adults approach learning pragmatically. They learn best from projects,applications and trying out some principles. These are the active experimenters .

Learning in adults is facilitated in an atmosphere which:


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1. Encourages the learner to be active.2. Promotes and facilitates the learners discovery of the personal meaning of ideas.3. Emphasizes the uniquely personal and subjective nature of learning.4. Realizes the difference is good and desirable.5. Consistently recognizes peoples right to make mistakes.6. Tolerates ambiguity.7. Considers evaluation as a cooperative process with emphasis on self-evaluation.8. Encourages openness of self rather than concealment of self.9. Encourages people to trust in themselves as well as in external sources.10. Makes people feel that they are respected.11. Makes people feel that they are accepted.12. Permits confrontation.

Teachers who teach adults should therefore consider the following principles of adult learning:1. Learning is an experience, which occurs inside the learner and is activated by the learner.2. Learning is the discovery of the personal meaning and relevance of ideas.3. Learning is a consequence of experience.4. Learning is a cooperative and collaborative process.5. Learning is an evolutionary process.6. Learning is sometimes a painful process.7. One of the richest resources fro learning is the learner himself.8. The process of learning is emotional as well as intellectual.9. The process of problem-solving and learning are highly unique and individual.

As such, adult learning should consist of a cycle that involves 4 steps: Experiencing (concrete experiences), processing(reflective observation), generalizing (abstract conceptualization) and applying (active experimentation). The interrelationships

between these steps are shown in the following diagram:

EXPERIENCING(concrete experiences)

Using the experience participants have hadalready or providing themwith an experience thatfurthers learning

APPLYING(active experimentation)

Modifying old behaviorsor testing new behaviorsand practicing them ineveryday situations

PROCESSING(reflective observation)Discussing theexperiences participantshave had already or sharing reactions andobservations of theactivity provided

GENERALIZING(abstract

conceptualization)Finding general trends andtruths in the experience that

participants have had alreadyor forming reactions to newexperiences intoconclusions, new concepts,theories


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The Inductive MethodThere are two fundamental approaches to the learning process: the deductive method and the inductive method . The

deductive method is referred to as pedagogy and will not be discussed. Focus is on the inductive method because it embodies allthe principles of adult learning.

There are seven steps in the inductive method:1. Setting the climate

Here, the teacher makes every effort to build an atmosphere conducive to learning.2. Determining the learning objective

This starts with life experiences, and involves issues, dilemmas, problems and concerns.

3. DoingIn this step, the issues, dilemmas, problems and concerns are opened by making use of structured exercises, casestudies, verbal descriptions, role plays, or personal reports.

4. Looking, ObservingThis focuses on what happened. IT examines what happened as closely as possible, and describes it as accuratelyas possible.

5. Thinking, Analyzing, ReflectingThis step ask questions on What can we learn from the facts?, Why did what happened, happen?, What areunderlying problems?, What are the implications?, What can we learn?.

6. Generalizing, Looking for InsightsAt this step, learner reach a conclusion, arrive at a principle or a generalization about what has been learned, or even relate this to an existing theory.

7. ActingIn this step, the learner decides to act immediately, to delay acting, or not to act at all, as he sees fit.

Both the deductive and the inductive methods of learning have their place in training and education. Theinductive method offers that path of least preparation, and is thus more popular among teachers. As such, the deductivemethod is used too much beyond what is good for learning.

Phases of LearningThe process of learning involves the following phases:1. Motivation phase

In order fro learning to occur, the learner must be motivated. Motivation may either be:Incentive motivation (Achievement motivation)

In this type of motivation, a reward is given whenever a learner achieves a goal.

Expectancy

Step 1.Experiencing

(Activity, doing)

THE EXPERIENTIAL LEARNING CYCLE

THE ADULT LEARNING CYCLE

Experiencing

Generalizing

Applying Processing

Step 5. Applying(Planning more

effective behavior)

Step 2. Publishing(Sharing reactionsand observations)

Step 4. Generalizing(Inferring principles

about the real world)

Step 3. Processing(Activity, doing)


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This is a process generated within the leader in which an individual strive to achieve a goal inanticipation of a reward. Such a reward may be on the near horizon. (e.g. scholarship) or on the far horizon (e.g. success as a professional).

2. Apprehension phaseOnce a learner is motivated, the next step is reception of information. The learner must attend to the parts of

stimulation that are relevant to his learning purpose. If he is listening to an oral communication (e.g. lecture) hemust focus on its meaning a set of sentences, and not on the accent or pronunciation of the lecturer. If he is readinga textbook, he must attend to its meaning, and not on the arrangement of topics or print type. If he is observing ademonstration, he must focus on the events and objects displayed, and not on the mannerisms of the demonstrator.

The process of attention involves a temporary internal state ( mental set ) or readiness. The mental set adapted by the learner determines what aspects of the external stimulation are perceived. In other words, the registration of stimuli by the learner involves selective perception , and depends on previous learning, verbal cues, and direction.In order for selective perception to take place, the various features of external stimulation must be distinguished or discriminated.

3. Acquisition phaseOnce the external stimulation has been attended to and perceived, learning cam proceed. The acquisition

phase id that moment in time when new information enters short-term memory . During this phase, the material istransformed into a form, which is mist readily stored. This process is called coding . As a result, the material issometimes distorted, and may either be simplified of embellished. Distortion becomes less if stimuli are groupedin certain ways, either as concepts or as principles.

4. Retention phaseThis phase involves entry of learned entity into long term memory . This is the phase of learning that is least

known because it is the least accessible to information.5. Recall phase

In this phase, in order to find out whether there ha been a more or less permanent behavior modification, thelearned modification is recalled so that it can be exhibited a performance. The process involved is called retrieval .

Retrieval may be affected by external stimulation, and cues may be suggested to accelerate retrieval. Asophisticated learner supplies his own retrieval cues, and is thus called an independent learner .

6. Generalization phaseRetrieval of what is learned does not always occur in the same situation or within the same context that

surrounded the original learning. As such, there must be generalization of the learning that has occurred.The recall of what has been learned and its application to new and different contexts is referred to as transfer

of learning .7. Performance phase

During this phase, the response generator organizes the learners response and allows him to exhibit a performance that reflects what he has learned.

8. Feedback phaseMany learning theorists consider this as the essence of reinforcement . The process of reinforcement operates

in man not because a reward is actually provided, but because an anticipation of reward is confirmed.

Learning OutcomesThere are five major categories of learning outcomes proposed by Gagne in 1972. All of them still apply as of the present time. They are:1. Verbal information

This includes acquisition of facts, names, principles and generalizations. For students, this serves as anecessary prerequisite for further learning. For graduates and professionals, this will be of practical importanceduring the learners lifetime, and will provide a vehicle for thought.

2. Intellectual skillsThis includes knowing how aside from knowing what . It includes discrimination, concepts, rules and higher

order rules.3. Cognitive strategies

These are internally organized capabilities which the learner makes use in guiding his own attending,learning, remembering, and thinking. These govern the learners own behavior in dealing with his environment.As a result, the learner increasingly becomes a self-learner and an independent thinker .

4. Attitudes

An attitude is an acquired internal state that influences the choice of personal action toward some class of things, persons or events. Many kinds of attitudes can be identified as desirable educational goals.

5. Motor skillsThese are learned capabilities that make possible the precise, smooth, and accurately timed execution of

performance involving the use of muscles.

MemoryMemory is the retention and storage of learned material. From the physiologic point of view, memory can be divided

into two forms: explicit memory ad implicit memory.Explicit memory (declarative memory, recognition memory) is associated with consciousness or awareness and is

integrated in the hippocampus and adjacent entorhinal, perirhinal and parahippocampal portions of the medial temporal cortex . Iconsists of memory for events (episodic memory) and memory of words, rules and language (semantic memory). The amygdalais closely associated with the hippocampus and is concerned with encoding emotional memories.


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Intrinsic memory (nondeclarative memory, reflexive memory) does not involve awareness. Its retention does notinvolve processing in the hippocampus but is presumed to be integrated in the striatum and certain parts of the cerebellum. Itconsists of nonassociative memory (habituation and sensitization), associative memory (classical and operant conditioning), skillsand habits, and priming.

Both explicit and implicit memory involve three stages:1. Sensory memory

Stimulation from the learners environment affects his receptors and enters the nervous system via a sensoryregister. This is the structure responsible for the initial perception of objects and events that the learner sees, hearsor senses. The information remains here for only the smallest fraction of a second.

2. Short-term memoryThis lasts from second to hours, during which, processing takes place in the hippocampus, where the

information is coded into a conceptual form. Material in short-term memory may last for a few seconds, but, if reviewed, may last for longer periods. During short-term memory, the memory traces are subject to disruption bytrauma and various drugs.

3. Long-term memoryThis involves storage of information for years, and sometimes, for life.

Memory can be classified into three types:1. Semantic memory

This refers to an individuals cumulative knowledge of the world such as language, concepts, and principles.2. Episodic memory

This relates to personally experienced events contextually bound to time and place. Loss can take place whenthe items to be recalled are not meaningful.

3. Procedural memoryThis refers to perceptual-motor skills or cognitive operations without intention or conscious awareness by the

individual.

Numerous hormones and neuropeptides have been found to affect learning and memory. Among these are:1. ACTH neuropeptides

These affect attention, concentration and motivational processes.2. Glucocorticoids

These eliminate learned behavior that is no longer relevant. Also, cortisol is believed to enhance excitabilityof neurons.

3. Neurohypophyseal hormones and related neuropeptidesThese modulate storage and retrieval of information. Neuropeptides related to vasopressin facilitate storage

and retrieval of information; neuropeptides related to oxytocin inhibits storage and retrieval if information.4. Release peptides and release-inhibiting peptides

These affect learning and memory via:their influences on metabolic and endocrine processes; and

their ability to elicit emotional and autonomic responses.As a rule, CNS stimulants like caffeine, physostigmine, amphetamine and nicotine, as well as CNS

convulsants like picrotoxin, strychnine and pentylenetetrazol have been found to improve memory. However, the sideeffects or adverse effects of these drugs far outweigh their use as memory enhancers and are thus not recommended,except perhaps for caffeine (in moderation).

There are three special states of memory:1. Hypermnesia

This refers to unusual memory for detail of a specific or selected situation.2. Iconic memory

This refers to the brief, detailed retention of visual stimuli.3. Eidetic memory

This refers to the unusual ability to glance at an object like a book page, look away, and recite the contents withouterror, as if reading the page.

ForgettingWhy do we forget? There are three theories of forgetting:

1. Trace decay theoryAccording to this theory, what is learned makes some sort of change in brain cells, which gradually fade withtime.

2. Interference theoryAccording to this theory, forgetting is due to inhibition of old impressions and association by new ones. Whenmaterial is organized, and learning is meaningful, the effect of interference is reduced.

3. Assimilation theoryAccording to this theory, memory is active, and as new learning takes place, some old material is removed tomake room for new material.

Disorders of MemorySome of the disorders of memory include the following:

1. Alzheimers disease


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This involves progressive loss of memory and cognitive function in middle age. Cognitive decline is correlatedwith loss of synapses initially involving the parietal and temporal lobes, with relative sparing of the frontal lobe.

2. Senile dementiaThis is similar to Alzheimers disease, only that loss of memory and cognitive function occurs in the elderly

population (60 and above).3. Confabulation

In this disorder, the individual weaves data from the here-and-now into a recalled experience.4. Paramnesia

This refers to a distortion of remembered data.5. Patchy amnesia

In this disorder, the person has intact memory around a given amnesia hole.6. Anterograde amnesia

This is characterized by loss of memory following a given significant life event, usually traumatic.7. Retrograde amnesia

This is characterized by loss of memory for events immediately preceding a significant life event. Again, the lifeevent is usually traumatic.

addtl notes:CAFFEINE (if youre sleepy) DO NOT TAKE MILK

Coffee (5 oz cup) when youre preparing a studyinstant available = Tryptophan

percolatedTea (5 oz cup)

brewinstant

Soft drinks (12 oz)mountain dewtab (cans)cokeshasta

pepsiRC colaRed bull

MEMORY TRICKSacronymacrosticlink

peg

location systemrhymes and jinglessubstitute words and homonymsverbatim memorizing

BEST CONDITIONS FOR MEMORIZINGGet yourself some privacy.Be alert.Put aside other problems.Fill your stomach comfortably full.Avoid alcohol or drugs.Alternate between concentrating (45 min) and relaxing (15 min).Develop a positive attitude.

Module 1: Chipped Away


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Instructional Objectives:At the end of this module the student is expected to:

1. Identify the toxic chemical component of cassava.

2. Discuss the structure and functions of the cell.2.1. Identify/Recall the cell if given description or microscopic slide.2.2. Identify the various organelles, inclusions and cytoskeleton if given descriptions.2.3. Identify the differences between organelles and inclusions.2.4. Identify the roles of organelles and cytoskeleton.2.5. Identify the following when given descriptions.

2.5.1. cell cycle and its phases2.5.2. mitosis and its stages2.5.3. meiosis and its stages

3. Identify/describe the 3 major sources of high-energy phosphates that take part in energy conservation or energy capture.

4. Identify definition of respiratory chain, electron transfer, redox pair & oxidative phosphorylation.Identify the importance of standard reduction potential.Identify the standard reduction potential fro the common redox pairs.

5. Identify the descriptions of the respiratory chain & oxidative phosphorylation.

6. State the 4 major groups of inhibitors of mitochondrial ATP synthesis and their examples.

7. State/identify the mechanism of action of cyanides.Recall the MLDL of cyanides.

8. Enumerate/recall the diagnostic signs and symptoms of cyanide poisoning.

9. State/identify the treatment of cyanide poisoning.

1. Identify the toxic chemical component of cassava.Cassava contains cyanogenic glycosides (linamarin ) w/c is converted to toxic hydrocyanic acid or prussic acid when itcomes in contract with linamarase.


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2. Discuss the structure and functions of the cell.2.1. Identify/Recall the cell if given description or microscopic slide.The cell is the smallest unit of the living structure capable of independent existence. It is composed of two basic parts:cytoplasm and nucleus. The size varies from 8 to 200 m.

Size: mycoplasmas (smallest)Shape: lining of blood vessels & body cavities flattened

line ducts of glands cuboidalline most of the digestive tract rectangular & columnar RBC biconcave disksskeletal muscle elongated & fusiformnerve cells irregular in shape & possess elongated processes

Nucleus- contains blueprint for all cell structures & activities encoded in the DNA of the chromosomes- largest organelle in cell- 3 major components:

o chromatin, genetic materialo nucleolus, site of rRNA synthesiso nucleoplasm, macromolecules & nuclear particles (maintenance of cell)

- nuclear envelope: 2 parallel unit membranes that fuse to form nuclear pores- fibrous lamina: lamins A, B, C; stabilize nuclear envelope- nuclear pores: controlled pathways between nucleus & cytoplasm- chromatin: 2 types

o heterochromatin electron denseo euchromatin less coiled; nucleosome, basic structural unit

- nucleolus: spherical, 2 distinct component:o nuclear organizer o pars fibrosao pars granulosa

- nuclear matrix: fits space between the chromatin & nucleolio nucleoskeleton formation of a protein base to w/c DNA loops are bound

Cytoplasm- surrounds the nucleus and is bounded by the plasma membrane- region of the cell responsible for the formation & release of energy, fro the synthesis of proteins, for growth

and motility and for the many other functions- area for the cell where most of the work is accomplished- components are organelles, inclusions, & matrix

2.2. Identify the various organelles, inclusions and cytoskeleton if given descriptions.Organelles include:

MITOCHONDRIA double membrane, powerhouse of the cell (ATP production), affected by toxic subs.a. outer membrane porin

b. inner membrane cristaec. intermembrane space/outer chamber d. matris space/mitochondrial matrix/inner chamber

RIBOSOMES protein synthesis w/c composed of tRNA and protein

ENDOPLASMIC RETICULUM functions as mechanical support, synthesis of proteins and transportRough ER maker of secretory proteins such as glycoproteins, protein secretion, consist of cisternae,

presence of polyribosomes, synthesis of phospholipids, and initial glycosylation of glycolipidsSmooth ER lacks polyribosomes, lipid synthesis, metabolism of CHO, & detoxification of drugs & poisons

GOLGI APPARATUS glycosylation of lipids and proteins, cell secretion, it finishes, sorts, and ships cell products,has cisternae LYSOSOMES contains hydrolytic enzymes, diegestive compartments, suicide bag

PEROXISOMES oval bodies enclosed by single membrane that transfer hydrogen from various substances to oxygen producing and then degrading hydrogen peroxide

PROTEOSOMES are multiple-protease complexes that digest targeted fro destruction by attachment to ubiquinone

Inclusions include:FOOD SUBSTANCES carbohydrate, fatsGLYCOGENPIGMENTS


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a. carbon phagocytosed by macrophages in the RS b. carotene carrots and tomatoesc. silver and leadd. hemosiderin & bilirubine. melaninf. lipofuschin golden brown pigment found in the liver, nerve, & heart cells

2.3. Identify the differences between organelles and inclusions.Organelles are living substances performing definite functions. Inclusions are inert or non-living substances that do not

perform definite functions.

2.4. Identify the roles of organelles and cytoskeleton.Cytoskeleton/Cytomusculature

- a network of fibers extending throughout the cytoplasm- it provides structural support to the cell, cell motility, and regulation- 3 main types of fibers;

1. microtubules (thickest) tubulin, provide framework that maintains the processes cylindricalshaped for movement; centriole and centrosome (9+2)

2. microfilaments/actin filaments3. intermediate fibers myosin; producing forces associated with cell movements

2.5. Identify the following when given descriptions.2.5.1. cell cycle and its phasesThe Cell Cycle is the alternation between mitosis and interphase.Phases: G1, S, and G2

Following Mitosis (M), cells initiate a new cycle (G1) in w/c RNA and protein synthesis takes place, and cellvolume, previously reduced by in mitosis is restored to normal size cells may become nondividing (G o) ocontinue through G1 where they become committed to begin DNA synthesis (S) and complete the cell cycle(G2), the site of accumulation of energy to be used for mitosis and the synthesis for tubulin to be assembled inmicrotubules during mitosis and then proceed to mitosis (M) again. Following mitosis, two daughter cells are

produced. 2.5.2. mitosis and its stagesMITOSIS is a form of cell division resulting in the production of two cells, each with the same chromosome number and genetic complement as the parent cell.Phases:

Prophase : condensation of chromosomesPrometaphase : chromosomes take on the appearance of double structures, each represented by a pair of

sister chromatids

Metaphase : chromosomes line up on the equatorial plane of the cellAnaphase : sister chromatids of each chromosomes are pulled apart and directed toward the opposite polesTelophase : completes daughter cell formation and is characterized by cytokinesis (division of cytoplasm)

2.5.3. meiosis and its stagesMEIOSIS is the process in gametogenesis during w/c one replication of the chromosomes is followed by two divisionsto produce four haploids.Stages: Meiosis is a continuum composed of two phases.

Meiosis I : homologous chromosomes replicatesubstages: Leptotene, Zygotene, Pachytene, Diplotene, Diakinesischromosomes duplicate so that there would be 23 pairs of duplicated chromosomes in all(22 pairs of autosomal and a pair of sex chromosomes)genetic exchange occurs due to crossing over at the completion of this stage, the daughter cell has 23 haploid number of duplicated andcrossed over chromosomes

Meiosis II : sister chromatids separateno additional duplication of DNA occurschromatids separate so each daughter cells has the haploid no. of duplicatedchromosomes

**when two haploid gametes fuse, a mature oocyte is formed in females and a mature spermatozoon formedfrom one male and thus a new individual is formed, a diploid zygote

Table 1: Comparison between Meiosis I and Meiosis II


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3. Identify/describe the 3 major sources of high-energy phosphates that take part in energy conservation or energy capture.

GLYCOLYSIS breaking down of sugar, the major pathway found in the cytosol of all mammalian cells for themetabolism of glucose to pyruvate and lactate; it is also a main pathway for the metabolism of fructose and galactosederived from the diet and also provides ATP in the absence of oxygen; has a net formation of 2 high energy phosphates.

CITRIC ACID CYCLE/KREBS CYCLE/TCA is a series of reaction in the matrix of the mitochondria that bring aboutcatabolism of acetyl residues, liberating equivalents w/c leads to the release and capture of ATP; generates little amount of energy, by the conversion of succinyl CoA to succinate, one ~P is produced in the cycle thus, in a molecule of glucose thetwo turns of the TCA produces 2~P.

OXIDATIVE PHOSPHORYLATION is a system in the mitochondria that couples respiration to the generation of ATP. It has the greatest quantitative source of ~P in aerobic organisms.

4. Identify definition of respiratory chain, electron transfer, redox pair & oxidative phosphorylation.

Respiratory chain or ETC series of catalyst that collect and transport reducing equivalents and direct them to their final reaction with oxygen to form water

Electron transfer reaction occurs when electrons are transferred between an electron donor (reducing agent) and anelectron acceptor (oxidizing agent)

Redox pairs in a reaction w/c one losses electron (oxidation) and the other gains electron (reduction)e.g. NADH/NAD+

Oxidative Phosphorylation a system in the mitochondria that couples respiration to the generation of the high

energy intermediate, ATP

Identify the importance of standard reduction potential.

1) It is a measure (in volts) of the relative affinity of the electron acceptor of each pairs of electrons.2) It allows prediction of the direction of the flow of electrons from one redox couple to another.3) It also indicated that the more negative the value, the greater is its capacity to yield electrons and the more

effective it is as a reducing agent.4) It makes possible to calculate the overall change in free energy across the entire transport chain beginning

with NADH.

Identify the standard reduction potential fro the common redox pairs.

System E o voltsH+/H2 - 0.42

NAD+/NADH - 0.32

Lipoate;ox/red - 0.29Acetoacetate/3-hydroxybutyrate - 0.27Pyruvate/lactae - 0.19Oxaloacetae/malte - 0.17Ubiquinone;ox/red + 0.10Cytochrome c1; Fe+/Fe+ + 0.22Cytochrome a; Fe+/Fe+ + 0.29Oxygen/water + 0.82

5. Identify the descriptions of the respiratory chain & oxidative phosphorylation.

Respiratory Chain This involves transfer of electron from one substrate to another, w/c would release H+ as well asenergy. This H+ and energy will be used in oxidative phosphorylation.

Stages Meiosis I Meiosis II

Prophase each homologues is composed of two sister chromatids that synapse and formed bivalentsduplicated chromosomes are present; one fromeach pair of homologous chromosomes

Metaphase bivalents are at the equator duplicated chromosomes are at the equator

Anaphase homologues separate and move to opposite poles centromeres divide and daughter chromosomesmove to the opposite poles

Telophase at each pole, there is one homologue from each pair of homologous chromosomesat each pole, there is the haploid no. and one of each kind


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Oxidative Phosphorylation During the RC in the mitochondrial membrane, the transfer of electrons from 1 substrate toanother releases H+ as well as energy. The energy released during the oxidation pumps the H+ ions to the outer surface of the inner membrane. Because of this, substrates that are integrated into the complexes also act as proton pumps.

Proton pumps push H+ into the outer surface of the membrane creating a proton circuit. The accumulation of protons (H+)of the outside membrane creates electrochemical potential deferences across the membranes. This is characterized by achange of pH and an electron gradient. The generated gradient, in turn, activates ATP synthase located at the several proteinsubunits known as F1-F0 complex . H+ in the protein circuit moves inward the mitochondrial matrix via F1-F0 subunits. Thegradient produced by the passing protons are utilized by the activated ATP synthase to phosphorylate ADP and Pi formingATP to result in oxidative phosphorylation produces 11 ~P in the form of ATP.

6. State the 4 major groups of inhibitors of mitochondrial ATP synthesis and their examples.1) Proton pump inhibitors or Respiratory chain inhibitors

block respiration in the presence of either ADP uncouplersarrest respiration by blocking the RC act at 3 sites and can therefore totally arrest respiration

block both electron transport and proton pumpe.g. cyanide and carbon monoxide: inhibits cytochrome oxidase

antimycin A: block electron transfer from cyt b to cyt crotenone and piericidin A: block by combining stoichiometrically w/ NADH-dehydrogenaseamobarbital myxothiazol DCMU-3-1,1 dimethyl urea

2) Phosphorylation inhibitors or Inhibitors of ATP synthase or Oxidative phosphorylationabolish the burst of O 2 consumption after adding ADP but have no effect on uncouplers stimulated respirationinhibitors w/c block oxidation and phosphorylatione.g. oligomycin: completely block oxidation & phosphorylation in intact mitochondria. However, by

the presence of the uncoupler dinitropheno l, oxidation proceeds w/o phosphorylation indicatingthat oligomycin does not act directly on the RC but subsequently on a step in phosphorylationaurovertin: inhibit F 1venturicidin: inhibit F o and CFoDCCD (Dicyclohexyl carbodiimide): block proton flow through C o and CFo

3) Transport inhibitors or Inhibitors of ADP/ATP translocaseeither prevent the export ATP or the uniport of raw materials across the mitochondrial inner membraneinhibits adenine dinucleotide translocaseinhibits the transporter of ADP into the mitochondriae.g. atractyloside: w/c inhibits OP that is dependent on the transport of adenine nucleotide across the

inner mitochondrial membrane boukrekic acid NEM

4) Krebs cycle inhibitors or Uncouplers

w/c block one or more of TCA cycle enzyme, or an axillary rxns.action of the uncouplers is to dissociate oxidation in the respiration chain from phosphorylatione.g. 2,4 dinitrophenol valinomycin thermoyenin

arsenite aminooxyacetate FCCP

7. State/identify the mechanism of action of cyanides.Cynide inhibits mitochondrial cytochrome oxidase and blocks electron transport resulting in decreased oxidativemetabolism and oxygen utilization. Results in lactic acidosis.

Recall the MLD (minimum lethal dose) of cyanides.at average fatal adult dose of hydrogen cyanide is 50-60 mgcyanide poisoning in women can lead to teratogenic effects on the fetusadult men most predominantlethal dose: NaCN (sodium cyanide salts) = 150 mg

KCN (potassium cyanide salts) = 200 mgHCN (hydrogen cyanide gas) = 50 mg

8. Enumerate/recall the diagnostic signs and symptoms of cyanide poisoning.A. Initial effects

headache faintnessvertigo excitementanxiety burning sensation (mouth and throat)increase heart rate hypertension*nausea and vomiting are common; a bitter almond odor may be detected on the breath

B. Later effectscoma convulsions

paralysis respiratory depression pulmonary edema arythmias


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bradycardia hypotension

C. Exposed to small moderate amountsrapid breathing restlessnessdizziness weaknessheadache eye irritationnausea vomitingrapid heart beat

D. Exposed to large amountsconvulsions very slow heart beatloss of consciousness breathing stops

9. State/identify the treatment of cyanide poisoning.Amyl nitrite (ampule), Sodium nitrite (IV), Sodium thiosulfate (IV)The rationale for nitrite therapy is that the nitrites cause formation of methemoglobin by combining withhemoglobin. Methemoglobin has a higher affinity for cyanide than cytochrome oxidase and thus promotes itsdissociation from this enzyme. Thiosulfate reacts with cyanide so the latter is slowly released fromcyanomethemoglobin, forming the non-toxic thiocyanate, w/c is excreted in the urine.

Pathway Rxn. catalyzed by Method of ~P prodn. No. of ~P formed per mole of Glucose

Glycolysis

Glyceraldehyde-3-phosphatedehydrogenase

Respiratory chain oxidation of 2NADH 6*

Phosphoglycerate kinase Phosphorylation at substrate level 2

Citric Acid Cycle

Pyruvate kinase Phosphorylation at substrate level 2

Pyruvate dehydrogenase Respiratory chain oxidation of 2NADH 6

Isocitrate dehydrogenase Respiratory chain oxidation of 2NADH 6

ketoglutarate dehydrogenase Respiratory chain oxidation of 2NADH 6

Succinate thiokinase Phosphorylation at substrate level 2

Succinate dehydrogenase Respiratory chain oxidation of 2NADH 4

Malate dehydrogenase Respiratory chain oxidation of 2NADH 6

Total per mole of glucose under aerobic respiration 38Total per mole of glucose under unaerobic respiration 2


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Module 2: A Fish Named WandaInstructional Objectives:

At the end of this module the student is expected to:

1. Identify the physico-chemical properties of the cell membrane.Identify the descriptions of each briefly.

2. Identify the different types of ion channels of the cell membrane.Identify descriptions of each.

3. Identify the types of membrane junctions formed by adjacent cell membranes.

4. Identify descriptions of the different processes involved in the transport of solutes and solvent across the cell membrane.

5. Identify the differences between:5.1. Simple diffusion and facilitated transport5.2. Facilitated transport and active transport5.3. Primary and secondary active transport5.4. Endocytosis, exocytosis and transcytosis

6. Predict whether a substance would be transported across the cell membrane or not, given the concentration of the substanceintracellularly and extracellularly, as well as its relative permeability. Assuming the substance is transported, predict thedirection of transport.

7. Predict the possible effect on cells subjected to varying concentrations of solutions (hypotonic, isotonic, hypertonic).

8. Identify the membrane potentials as to the following:8.1. Types and their descriptions8.2. Mechanisms involved8.3. Ionic bases

9. Identify the series of events, in sequence that takes place in the cell membrane of an excitable cell, from the time anadequate stimulus is applied up to the time an action potential develops.

10. Identify/Describe the mechanism of conduction of:10.1. graded potential10.2. action potential in myelinated and unmyelinated axons


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1. Identify the physico-chemical properties of the cell membrane.Identify the descriptions of each briefly.

CELL MEMBRANESFunctions:

a) separates cellular contents from extracellular fluid b) serves as a physical barrier that regulate the transport of substance into/out of the cellc) maintains the composition of the intracellular membraned) contains sites of reception of external stimuli or humoral messengers, w/c regulate cell activity

Structure:FLUID MOSAIC MODEL

proposed by singer and Nicholson in 1972cell membrane is composed of lipid bilayer in w/c globular proteins insert into and float within the

bilayer membrane has a very elastic strx., only 7.5 to 10 nanometers thick it is composed of proteins (55%), phospholipids (25%), cholesterol (13%), other lipids (4%), andcarbohydrates (3%)

Characteristics:a) its a lipoprotein complexb) possesses the property of semipermeability

allows substances of small molecular size to pass through largely attributed aqueouschannels formed by integral proteins

c) possesses the property of selective permeability allows movement of large molecules across it provided that molecules are needed by the

cell; attributed to integral proteins, w/c provide mechanisms for movt. of certain subs.d) behaves as a core conductor

ability of the cell membrane to allow the spread of excitation from one part to the rest of the membrane

e) acts as a condenser ability of the cell membrane to store large amounts of energy (ATP) w/in it

f) acts as a rectifier ability of the cell membrane to go back to its original state after excitation

g) acts as a resistor limits movement of ions across the cell membrane as a result of friction offered the

membrane to the flow of substances across ith) serve as receptor sites

include receptors for the following substances: peptide hormones, neurotransmitters,microbial products, viruses, lectin, and antigens

membranes receptors can be proteins, glycoproteins, lipids, or glycolipids

PROTEINS2 types:

1) Intrinsic or Integral Proteins- 70% of the membrane proteins- they penetrate the membrane- are amphipathic (the uncharges hydrophobic portions are located in the anterior of

the membrane, charged hydrophilic portions lies in the surface)- most span the entire membrane (transmembrane proteins): have 2 polar regions, one

on each side of the membrane and are connected by a nonpolar segment in thenonpolar interior of the membrane

2) Peripheral or Extrinsic Proteins- do NOT penetrate the membrane, are attached to the regions of one of the integral

proteins or polar heads of the lipids; are NOT amphipathic; usually located on thecytoplasmic aspect of the cell membrane

**Membrane proteins can serve as (1) channels, (2) carriers, (3) pumps, (4) receptors, and (5) enzymes**Protein kinase C is an impt. signal transduction protein**Fibronectin help cells to attach via all surface glycoproteins called integrins

LIPIDSare amphipathic (hydrophilic/polar at one end and hydrophobic/nonpolar at the other end)


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major lipid are phospholipids (phosphate radical is hydrophilic & polar while the fatty acid radical ishydrophobic & nonpolar)hydroxyl radical of cholesterol is hydrophilic while its steroid nucleus is hydrophobicglycolipids may function as receptors for antigenscholesterol/phospholipids ratio is inversely proportionate to the fluidity of the membrane4 major phospholipids:

o phospahtidylcholine addtl grp: choline outer o sphingomyelin addtl grp: choline outer o phosphatidylethanolamine 1 amino inner

CARBOHYDRATESare found projecting from the external surface of the membrane bound to lipids (glycolipids), form a fuzzycoat on cell surface referred to as glycolcalyxfunctions:

o protection of the cell from interaction with inappropriate proteins, from both physical & chemicalinjuries

o for cell-to-cell recognitiono for cell adhesion

2. Identify the different types of ion channels of the cell membrane.Identify descriptions of each.

Ungated Channels or Leak Channels always open; e.g. K+ leak channels

Gated Channels3 types:

1) voltage- gated channels : opening & closing of gates depend on the membrane potential: e.g. some Na+ & K+ channels

2) ligand-gated channels : require initial binding w/ substance (ligand) before channels open: extracellular mediator e.g. neurotransmitter-gated channels: intracellular mediator e.g. nucleotides & ions such Ca++

3) mechanically-gated channels or stretch activated channels : respond to mechanical distortion: e.g. hair cells of inner ear

3. Identify the types of membrane junctions formed by adjacent cell membranes.

TIGHT JUNCTIONS or ZONULA OCCLUDENSMost apical principal fxn is to form tight seal that prevent the flow of material between epithelial cells

(paracellular) in either direction; seal adjacent epithelial cells in a narrow band just beneath their apical surface.

ZONULA ADHERENS or FASCIA ADHERENS or ADHERING JUNCTIONSThis junction encircles the cell; a noteworthy feature is the insertion of numerous actin microfilaments.hold epithelial cells and cardiac muscles tightlycadherins: transmemebrane proteins whose extracellular segments bind to each other catehin: connected to actin filaments

GAP JUNCTIONS or NEXUSintracellular channels 1.5 to 2 nm in diameter that allows to free passage ions & molecular bet. them; permitsmembrane potential to pass from cell to celloccur almost anywhere along the lateral membrane; found in nearly all mammalian tissues-skeletal muscle is amajor exceptionconstructed 4 copies of transmembrane protein called connexinsgap jxn protein unit called connexins from hexamins with a hydrophilic pore, individual unit of the gap jxn is calleda connexon : connexon in adjacent cell membranes are aligned to from a hydrophilic channel bet. two cellsmetabolic inhibitors esp. that block OP can inhibit the formation of jxns

DESMOSOMES or MACULA ADHERENSa complex disk-shaped structure at the surface of one cell that is matched with an identical strx. at the surface of thecellonly fxn appears to be that of providing as esp. firm adhesion of one cell to the nexthemidesmosomes: half of a desmosome; in the contact zone between certain epithelial cells & basal lamina

Functional point of view on classification:1) Adhering junctions: zonula adherens, hemidesmosomes, & desmosomes


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2) Impermeable or tight junctions: zonula occludens3) Communicating junctions: gap jxns

4. Identify descriptions of the different processes involved in the transport of solutes and solvent across the cell membrane.

Transport across, but not through membranes all require metabolic energyEndocytosis a region of plasma membrane is pinched off to form an endocytic vesicle inside the cell. During vesicleformation, some fluid, dissolved solutes & particulate mat7eri7al from t7he7 ext7racellular medium are trapped inside thevesicle & internalized by cell.

Types of endocytosis:a) Phagocytosis (cell eating) ingestion of large particles or microorganisms & usually occur only in

specialized cells such as macrophagesb) Pinocytosis (cell drinking) produce smaller endocytic vesicles (0.1 0.2 m in diameter) than

phagocytosis. It is also known as a constitutive process because it occurs continually & specific stimuli arenot requires.Types of Pinocytosis:

fluid-phase endocytosis a nonspecific uptake of the extracellular medium & all its dissolvedsolutes

receptor-mediated endocytosis a more efficient process that uses receptors on the cellsurface to

bind specific molecules

Exocytosis a process of excreting impt. macromolecules out of the cell. These molecules are synthesized in the ER,modified in the Golgi complex, and packed inside the transport vesicles. These transport vesicles move to the cell surface,fuse to the cell membrane, and release the components outside the cell.

Transcytosis (cytopemsis) refers to the transport of material when it is first endocytosed, then the vesicle is transported tothe outer side of the cell where it fuses with the opposite plasma membrane and the content are released by endocytosis. Thisrequires energy.

Transport across and through membranes:Driving forces in the system:

a. concentration gradient/force or chemical gradient force b. electrical gradient across the membranec. pressure gradient: hydrostatic & osmotic pressure gradientd. metabolic energy in the form of ATP

Simple Diffusion free movement of molecules by random molecular motion (Brownian movt.). There will be net movt.of solute from an area of greater concentration to an area of lesser concentration of solutes; net movt. stops when theconcentration of solutes is uniform throughout the soln., diffusion is proportional to the area of the membrane and to theconcentration gradient.

The rate of net diffusion through a membrane follows Ficks law:J = - PA (C i Co) * if (-) J = effluxwhere: J = net rate of diffusion * if (+) J = influx

P = membrane permeability coefficientA = area of membraneCi = conc. of subs. inside membraneCo = conc. of subs. outside membrane

(Ci Co) = concentration gradient

2 types of Simple Diffusion:Diffusion through lipid matrix

- permeability to a substance increase with the lipid solubility of substance

- e.g. oxygen, CO 2, alcohol, FA

Diffusion through membrane channels or pores- diffusion of water-solute substance through the aqueous channels or pores formed by transmembrane

proteins- e.g. water, urea, ions

Osmosis net movt. of water (solvent) molecules from a region of high to low water conc. across a semi-permeablemembrane; can be prevented by applying pressure to the more concentrated soln., the amount of pressure required is ameasure of the osmotic pressure gradient bet. the 2 chambers.

Osmotic pressure: pressure that would have to be applied to the soln. to prevent water movt. into the soln. from acompartment of pure water.

The total solute concentration of a solution is known as its osmolarity or osmolality.


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Bulk flow and Solvent Drag large numbers of water molecules tend to stream through the pores in unison ( bulk ) rather than to move randomly as occurs in pure diffusion. When theres bulk flow, water tend to drag along some molecules of solutes: this is called a solvent drag .

Protein-mediated/carrier-mediated transport- require carrier transmembrane proteins- characteristics:

saturation there is a maximum rate at w/c the system can operate specificity specific to a substance

- 2 general types:1) Active transport

Primary Active Transport Processes - carrier-mediated & directly use energy in the form of ATP, include:a. Na-K pump or Na-ATPase exclude 3 Na+ from the cell & take 2 K+ into the cell for

each mole of ATP hydrolyzed

b. Ca++ pump in SR of muscle cellsc. K+/H+ pump of gastric mucosal cells

Secondary Active Transport Processes - make use of energy stored in an ion-concentration gradient that isestablished across the cell membrane by one of the primary pumps; includes:

a. Na-glucose symport or Na-glucose co-transport of Na+ and glucose form outside to inside of cell by the same carrier molecule

b. Na-Ca antiport or Na-Ca exchanger: 3 Na+ ions are transported into the cell for each Ca++ iontransported into the cell for each Ca++ ion transported out of the cell also called Na-Ca counterpart

2) Facilitated transport/Facilitated diffusion do NOT require energy; net transport is along a concentrationgradient

5. Identify the differences between:5.1. Simple diffusion and facilitated transport

Simple Diffusion Facilitated Transport Net movt. from higher to lower concentration Net movt. from higher to lower concentration

Do NOT require the presence of carrier proteins Require presence of carrier proteins

Does NOT require energy Does NOT require energy

Fluxes do NOT saturate Reaches a maximal flux since carrier proteins becomes saturated

5.2. Facilitated transport and active transport

Facilitated Transport Active Transport

Requires the presence of carrier proteins Requires the presence of carrier proteins

Net movt. from higher to lower concentration Move substances uphill(from region of lower to higher concentration)

Does NOT require energy Uses energy

5.3. Primary and secondary active transport

Primary Active Transport Secondary Active Transport

Carrier-mediated Carrier-mediated

Directly uses energy in the form of ATPMakes use of energy stored in an ionconcentration gradient that is established acrossthe membrane by one of the primary pumps

5.4. Endocytosis, exocytosis and transcytosis

Endocytosis Exocytosis Transcytosis


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Engulf or ingestion of extracellular materials

Extrusion of materials fromthe cell

Material is first endocytosed,transported to the other side of the cell, fuse with opposite

plasma membrane, thenexocytosed

Requires energy Requires Ca++ and energy Requires energy

6. Predict whether a substance would be transported across the cell membrane or not, given the concentration of the substance

intracellularly and extracellularly, as well as its relative permeability. Assuming the substance is transported, predict thedirection of transport.

7. Predict the possible effect on cells subjected to varying concentrations of solutions (hypotonic, isotonic, hypertonic).

Isotonic solution- if the total osmotic pressure of two solutions are equal, the solutions are said to be isoosmotic/isotonic- if the extracellular and intracellular osmotic pressures are equal, there is no net movement of water - at NaCl concentration of 154 mM, the volume of the cells is the same as their volume in plasma; this

concentration of NaCl is said to be isotonic to the red cell

Hypotonic solution- if solution A has less total osmotic pressure than solution B, A is said to be hypoosmotic/hypotonic to B- if the osmotic pressure of the ECF is lower than that of the cytoplasm, water enters the cell, the cell will continue

to

swell until the intracellular and extracellular osmotic pressure are equal- this also refers to a solution with a concentration less than 14mM

Hypertonic solution- if solution A has a grater osmotic pressure than solution B, A is said to be hyperosmotic/hypertonic with respect to

B- in a hypertonic solution, water leaves the cell ( cell shrinking ) and the cellular solutes become more concentrated

untilthe effective osmotic pressure of the cytoplasm is again equal to that of the ECF

- this refers to a solution with concentration greater than 154 mM

8. Identify the membrane potentials as to the following:8.1. Types and their descriptions8.2. Mechanisms involved8.3. Ionic bases

MEMBRANE POTENTIALS or transmembrane potential (Vm) refers to the voltage difference between the inside andoutside of the cell.

Diffusion Potential is the voltage difference (electric gradient) created by net diffusion of ions. The concentration gradientwhich causes net diffusion of particles from a region of higher to a region of lower concentration is called theCONCENTRATION FORCE.

1. Equilibrium potential (Veq)The equilibrium potential of a given ion species is the voltage difference of Vm which is equal in force butopposite in direction to the concentration force affecting the ion. At the Veq there is no net movement of the ion

because the forces acting upon it are exactly balanced.

The Veq of the different ions has been determined. In most neurons in the body, the Veq for K+ is about (-) 90mV, inside negative; the Veq of Na+ is about (+) 60 mV, inside positive. Thus, the Veq for each ion is different inmagnitude and possibly, even in direction from those for other ions since the concentration gradients are different.

The Veq for an ion can be determined by the NERNST EQUATION:

Veq = - 61 log [C]i at 37 C[C]o

where: Veq = equilibrium potential for a given ion[C]i = intracellular concentration of the ion[C]o = extracellular concentration of the ion

e.g. Veq K+ = - 61 log [K+]i[K+]o

2. The Resting Membrane Potential (RMP) or resting potential, or steady potential or polarized state


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Resting membrane potential is the electrical potential difference (transmembrane potential) between the inside andoutside of the cell that is not stimulated (a cell at rest).

All cells under resting condition have an electrical potential difference across the plasma membrane oriented sothat the inside of the cell is negatively charged with respect to the outside. This is due to the fact that there isslightly greater number of (-) charges than (+) charges inside the cell and a slightly greater number of (+) chargesthan (-) charges outside the cell.

How is the RMP established? According to Bernstein, it is due to the relative difference in the membrane permeability to the different ions present inside and outside of the cell as well as to the concentration gradient for each ion. It is estimated that the cell membrane in the resting state is 50-70 times more permeable to K+ than Na+.The intracellular concentration of K+ is about 145 mmol (meq/L), and the ECF concentration is about 4 meq/L,resulting in a 30:1 conc. gradient. An opposite gradient exists for Na+ ions: intracellular Na+ is about 15 meq/LECF concentration is about 150 meq/L. Normally at rest K+ tends to move out of the cell along its conc. gradient(from inside to outside of cell). Likewise Na+ tends to diffuse along conc. gradient (opposite direction). Sincemembrane is much more permeable to K+ than Na+, then passive K+ efflux (exit) will be much grater than

passive Na+ influx (entry). Thus, more positive ions are going out than (+) ions entering until the inside of the cellis negative relative to the outside. The point at w/c the outer membrane becomes positive and the inner negative isknown as the steady state of the cell , and the potential at w/c it occurs is known as the RMP. Thus, the RMP islargely due to K+ efflux (K+ exit).

The RMP can be measured directly by the use of microelectrodes, on electrode inserted into the cell, and another one placed outside the cell. The RMP range from (-) 50 to (-) 100 mV depending upon the cell. In nerve cells,RMP varies from (-) 70 to (-) 90 mV.

The RMP in nerves is usually at (-) 70 mV. At a resting potential of (-) 70 mV neither K+ nor Na+ is at itsequilibrium potential. Thus, there is net movement of Na+ into the cell and K+ out. If such net ion movementoccurs, you would expect the concentration of intracellular Na+ to increase and intracellular K+ to decrease.However, this does not occur; instead, conc. gradient of K+ and Na+ are maintained. This is because of theactivity of the Na-K pump. Thus, the Na-K pump also maintains the RMP. As long as the conc. gradients of Na+and K+ remain fixed and the ion permeabilities of the plasma membrane do not change, the electrical potentialacross the RMP will remain constant.

3. Graded Potentials (GPs)GPs are local changes in the membrane potential in either a depolarizing or hyperpolarizing direction. They areusually produced by some specific change in the cells environment (stimulus) acting on a specialized region of the membrane. They are called graded potentials because the amplitude of the potential change is variable(graded) and related to the magnitude of the external event w/c produces the change in membrane potential.

Whenever a local change in membrane potential occurs a current will flow between this region and the adjacent

regions of the plasma membrane that are at the resting potential. Thus, GPs cause to flow in the intracellular andextracellular fluids in the region around them. The greater the potential change, the greater the current flow. Byconvection, the direction in w/c positive ions move is designated the direction of current flow. Negatively charged

particles simultaneously move in the opposite direction.

Local current flow is decremental; i.e. its amplitude decreases with increasing distance; thus, the resulting changein membrane potential also decreases with distance form the site of origin of the potential.

*Characteristics of graded potentials:1) Response is graded and related to the magnitude of the external event2) Can be summated3) Has no threshold and has no refractory period4) Is conducted decrementally (amplitude decreases with distance)5) Duration varies with the initiating condition6) Can be a depolarization or hyperpolarization

7) May be initiated by a stimulus, a neurotransmitter, or may be spontaneous

*Examples of graded potentials include:a) Synaptic potential

EPSP (excitatory postsynaptic potential)IPSP (inhibitory postsynaptic potential)

b) Motor end plate potentialEPP (end plate potential)MEPP (miniature end plate potential)

c) Receptor potential (generator potential)d) Potential that occurs spontaneously; pacemaker potential

4. Action Potentials (APs)


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APs are rapid alterations in the membrane potential resulting in a reversal of membrane potential polarity from thenormal resting negative potential to a positive membrane potential and then ends with an almost equally rapidchange back again to the negative resting potential. (ex. from -70 mV to +30 mV then back to -70 mV) Thus, wehave the ff. phases of the AP:

1) Upstroke or depolarization phase this is the rapid depolarization of the membrane after threshold potential (TP) is reached. An AP occurs only when the membrane is depolarized fromits resting potential to its TP by a stimulus.

2) Overshoot this is the portion of the AP during w/c the membrane is positive. The peak of the APis the overshoot potential .

3) Down stroke or repolarization phase this is the rapid return of the membrane towards its resting potential. When repolarization is about 70% completed, the rate of repolarization decreases; thisslower fall is called after-depolarization .

4) Undershoot phase (hyperpolarization, after-hyperpolarization, positive afterpotential) themembrane potential becomes more negative than its resting value.

The major factor in the production of these phases is the voltage-gated or voltage-sensitive K+ and Na+channels. The voltage-gated Na+ channel has two gates: 1) activation gate or m gate w/c covers the extracellular sideof the Na+ channel, and the 2) inactivation gate or h gate w/c covers the intracellular side of the channel. Both gatesmust be open for Na+ to flow through the channel. When the m gate is open, the channel is said to be activated ; whenthe h gate is closed, the channel is said to be inactivated .

The voltage-gated K+ channel is regulated by a single gate, the n gate , w/c covers the extracellular side of

the channel. When the n gate is open, the K+ channel is activated. It does not have an inactivation gate.

The m and n gates close during the resting state, and open when the Vm is depolarized (less negative). The hgates open when the Vm is polarized (at rest) and closed during the resting state, these are not inactivated because the ngates are open.

The flow of ions during the AP is passive and depends upon the conc. gradient and on interactions amongions and with the channel.

The gating mechanism produces the phases of the AP. How?1) Upstroke this is due to a positive feedback cycle (Hodgkin cycle) or regenerative process. This is

the positive feedback relation between depolarization and increased Na+ permeability, w/c leads tothe rapid depolarizing phase of the AP. Recall that at rest, the m and n gates are closed and h gatesare opened. When stimulus depolarizes the membrane, m gates on some of the Na+ channels open

Na+ permeability increases more Na+ enters the cell membrane depolarizes further causes more m gates to open allows more Na+ to enter further depolarize the membrane and so on The process continues until all the voltage-gated Na+ channels have become totallyactivated (opened) cause reversal of polarity ( overshoot ) peak.

2) Downstroke this is due: a) inactivation of the Na+ channels, and b) activation of the K+channels. The same voltage change that opens the ma gates also closes the gate. However, closureof h gates occur a few milliseconds after the gates open. Closure of h gates stops the flow of Na+into the cell repolarization.

K+ channels are activated by the opening of the n gates K+ efflux repolarization.K+ channels open slowly; they mainly open just at the same time that Na+ channels are beginningto become inactivated (are closing).

The two events together (decreased Na+ entry and increased K+ efflux) greatly speedsthe repolarization process.

The h gates will reopen when the Vm returns to or nearly to the original RMP removing the inactivation of the Na+ channels.

3) Undershoot or positive afterpotential this is due to the slow losing of the K+ channels. The ngates close slowly when the membrane is repolarizing during the downstroke. Many K+ channelsremain open for several milliseconds after the repolarization process of the membrane is complete.This allows excess K+ ions to diffuse out of the nerve fiber membrane becomes more negative hyperpolarization (positive afterpotential). Eventually the n gates close and the Vm returns to itsresting level.

*Characteristics of after potentials:1) Response is all-or-none and amplitude is independent of initiating event. All-or-none means that

the nerve fiber under a given set of conditions gives a maximal response or no response at all.


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2) Cannot be summated3) Has a threshold that is usually 10-15 mV depolarized, relative to the resting potential4) Has a refractory period5) Is conducted without decrement; the amplitude is constant6) Duration is constant7) Is a depolarization (with an overshoot)8) Is initiated by membrane depolarization

5. Threshold Potentials (TP)

Threshold potential is the critical level of cell membrane depolarization at w/c an AP is initiated by a thresholdstimulus; this is also known as the firing level . The TP of most excitable membranes is a level about 15 mV moredepolarized than the RMP. Stimuli that are just strong enough to depolarize the membrane to this level are calledthreshold stimuli . If depolarization is less than threshold, the positive feedback cycle is not triggered and no APoccurs; the membrane will just return to its resting level as soon as the stimulus is removed.

These weak depolarization are subthreshold potentials , and the stimuli that cause them are subthreshold orsubliminal stimuli . Stimuli of more than threshold magnitude ( suprathreshold stimuli ) also elicit APs, but theAPs have exactly the same amplitude as those caused by threshold stimuli. This is because once threshold isreached; membranes events are no longer dependent upon stimulus strength: APs either occur maximally or theydo not occur at all (all or none law).

9. Identify the series of events, in sequence that takes place in the cell membrane of an excitable cell, from the time anadequate stimulus is applied up to the time an action potential develops.

10. Identify/Describe the mechanism of conduction of:10.1. graded potential10.2. action potential in myelinated and unmyelinated axons

Propagation of action potential in unmyelinated axon Once generated, AP must be conducted along the axon. Each AP triggers by local current flow, a new AP at an adjacentarea of the membrane. The new AP is identical to the old AP & the new AP produces local currents of its own whendepolarizes the next region adjacent to it produce another AP, & so on along the length of the membrane. The APreaching the end is identical to the initial one.Unmyelinated membrane, conduction is slower because it needs to be stimulated to the entire membrane.Once depolarized, no point of stopping.

Propagation of action potential in myelinated axon Myelin makes it more difficult for current to flow bet. intracellular and extracellular fluid compartments. Thus, APs donot occur along the sessions of the membrane protected by myelin (internode), but occurs at the node of Ranvier (pointof discontinuity bet. successive internodes). Thus, AP jumps from one node to the next as it propagates along amyelinated fiber.This method of propagation of AP from one to node is called saltatory conduction w/c causes more rapid propagation of AP.Fibers with myelin have faster rate of conduction that needs excitation because depolarization takes place only at thenodes of Ranvier.

Addtl notes:1) If measured transmembrane potential (Vm) = Equilibrium potential (Veq) of a particular ion

[Vm=Veq]that ion is in electrochemical equilibrium across the membrane

NO NET FLOW of that ion across the membrane

2) If Vm is of the same sign (+/-) but larger in magnitude then Veq of a particular ion [Vm>Veq;same sign]

electrical force is larger than conc. forcenet movt. in the direction determined by the electrical force

3) If Vm is of the same sign but less in magnitude than Veq of a particular ion [Vm


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Module 3: Some Like It HotInstructional Objectives:


1. Discuss the tissue.1.1. Identify tissue and its types if given descriptions.1.2. Identify epithelium and its types if given description or microscopic slide.

1.2.1. Identify the differences in characteristics & roles of each epithelium1.2.2. Recall occurrences of each type in the body1.2.3. Identify the descriptions of the various epithelial specialization

2. Discuss membranes.

2.1. Identify the descriptions of serous, mucous and cutaneous/skin membranes.2.2. Identify the differences in structure, occurrences, and roles between serous and mucous membranes.

3. Discuss a gland.3.1. Identify a gland if given description or microscopic slide.3.2. Identify the differences between:

3.2.1. exocrine & endocrine glands3.2.2. merocrine, apocrine, and holocrine glands3.2.3. serous, mucous and mixed glands3.2.4. simple and compound glands

Identify the parts of a gland as an organ of secretion.

4. Describe the skin.4.1 Identify the skin if given description or microscopic slide.

4.1.1. Identify the layers & sublayers

4.1.1.1. tissue content4.1.1.2. structural content4.1.1.3. vascular & nervous supply

4.1.2. Identify the roles of the skin

5. Identify the degrees and severity of burns. 6. Identify the kinds and the harmful effects of ultraviolet radiation (UVR).

7. Identify the various skin types and their sunburn sensitivity. 8. Identify the ways of preventing sunburn.

9. Recommend treatment of sunburn.

10. Given problems of the same nature relate problem to the epithelium and the integumentary system.


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TISSUE group of associated similarity structured cells that perform specialized functions1) Connective provide structural support; medium for exchange; reservoir of hormones controlling cell growth; aid

in defense & protection of body; storage of fat2) Muscle contract & relax; comprise striated, cardiac & skeletal.3) Nervous transmission of information; receive stimuli & conduct impulse4) Epithelial line internal surface of body; protects underlying tissues; transcellular transport of molecules;

secretion of mucous, hormones, enzymes; absorption of material from lumen; control movement of materials viaselective permeability; detection of sensations.

Epithelialtightly bound contiguous cells forming sheets covering/lining the bodydisplay little intracellular space & little extracellular matrix coz cells are close together separated from underlying connective tissues by extracellular connective tissue (basal lamina); basal surface rest on

basement membraneavascular thus they tend to bound to a connective tissue, nourishment is thru diffusionapical surface of membrane are specializedhigh mitotic activity & turnover of cells

Table 1. Types of Epithelia

Type Shape Locations Functions

SIMPLE

Squamous Flattened

Lining: alveoli, loop of Henle, parietal layer of Brownian capsule, blood & lymph vessels, inner &middle ear, parietal & pleuralcavities

Limiting membrane, fluid transport,gaseous exchange,lubrication/reducing friction, liningmembrane

Cuboidal Cuboidal Ducts of glands, ovary covering,kidney tubules Secretion, absorption, protection

Columnar Columnar Lining: oviducts, ductuli efferentes,uterus, small bronchi, digestive tractTransportation, absorption,

protection, secretion

Pseudostratified

Cells rest on basal lamina,not all reach

epithelialsurface

Lining: trachea, primary bronchi,epididymis, ductus deferens,auditory tube, tympanic cavity, nasalcavity, lacrimal sac, male urethra,large excretory ducts

Transportation, absorption, protection, secretion, & lubrication

STRATIFIED

Squamous(nonkeratinized)

Flattened(w/ nuclei)

Lining: mouth, epiglottis,esophagus, vocal folds, vagina Secretion, protection

Squamous(keratinized)

Flattened(w/o nuclei) Epidermis of skin Protection

Cuboidal Cuboidal Lining: ducts of sweat glands Absorption, secretion


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Columnar Columnar Conjunctiva of eye, large excretoryducts, portions of male urethra Secretion, absorption, protection

Transitional

Dome-shaped(relaxed)Flattened

(distended)

Lining: urinary tract, urethra Protection, distensible

Epithelial Specializations:1) Apical Domain

microvilli w/c are small fingerlike cytoplasmic protections emanating from the free surface of the cellinto the lumen; major function is transport & absorptionstereocilia w/c are long microvilli found only in the epididymis & in long sensory hairs of cochlea;usually rigid because of their core of actin filaments; increase surface area; function in signal generationcilia w/c are long motile hair like structures emanating from the apical surface; core is composed of complex arrangement of microtubules known as axoneme; propels mucus & other substance over thesurface of epithelium

2) Basolateral domain(in lateral membrane) occluding junctions w/c functions in joining cells to form an impermeable barrier,

preventing material from taking an intracellular route in passing across epithelial sheath, anchoring junctions w/c maintains cell-to-cell or cell-to-basal lamina adherens; communicating junctions w/c permits movement of ions or signaling molecules between cells, thus coupling adjacent cells bothelectrically & metabolically(in basal surface) plasma enfoldings w/c are enfoldings of the plasma membrane that increase surfacearea available for transport; hemidesmosomes w/c attach the basal cell membrane to the underlying basallamina

MEMBRANES epithelial layer and underlying connective tissue4 types:

1) Mucous membrane (mucosa) lines cavities open to the exterior (e.g. digestive, respiratory, excretory, reproductive tracts)

2) Serous membrane (serosa) lines cavities not open to the exterior. There are two parts the visceral & parietalmembranes w/c lines the pleural cavity (as pleural membranes), pericardial cavity (pericardium), and abdominopelviccavity (peritoneum). Each coelomic cavity is lines with a serous membrane, parietal (somatic) on the outer side &visceral on the inner side.

a) parietal (-pleura, pericardium, peritoneum) derived from somatic mesoderm. The parietal or somatic serousmembrane is on the outer side of the coelomic cavity, the side with embryonic parietal or somatic mesodermand ectoderm overlying.

b) Visceral (-pleura, pericardium, peritoneum) derived from splanchnic mesoderm. This is on the inner side othe coelomic cavity, the side with embryonic splanchnic mesoderm and endoderm beneath.

3) Cutaneous membrane (skin)4) Synovial membrane however, this is not really an epithelial membrane (therefore not a true membrane).

GLANDS originate from epithelial cells that leave the surface where they develop & penetrate into the underlying connectivetissue, manufacturing a basal lamina around themselves; parenchyma or the secretory units & stroma represents the elements of the connective tissue that invade & support the parenchyma; manufacture their product intracellularly by synthesis of macromolecules that are usually packaged & stored in vesicles called secretory granules ; secretory product maybe polypeptide

hormones, mucigen, milk, combination of lipid, protein & carbohydrates.2 types of glands based on method of distribution of their secretory products:

1) Exocrine secrete product via ducts2) Endocrine lost connections to the originating epithelium, thus secrete their product into blood or lymphatic vessels

for distribution

*cytokines are signaling molecules; perform the function of cell-to-cell communication released by signaling molecules; acton target cells w/c possess receptors for a signaling molecules

*glands that exhibit regulated secretory pathway concentrate & store their secretory products until the proper signalingmolecule for its release is received

*exocrine glands are classified accdng. to their secretions :


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a) mucous secrete mucinogens, large glycosylated proteins that upon hydration swell to become a thick viscous gel like protective lubricant known as mucin ; e.g. salivary of tongue & palate

b) serous membrane secrete an enzyme rich in watery fluid; e.g. pancreasc) mixed contain acini that produce mucous secretions as well as acini that produce serous secretions;

e.g. submandibular d) cytogenic produce living cells; e.g. testis & ovary

*exocrine exhibit 3 mechanisms for releasing their secretory products:a) merocrine release via exocytosis, as a result neither cell membrane cytoplasm becomes a part of the

secretion b) apocrine small portion of the apical cytoplasm is released along w/ the secretory glandc) holocrine secretory cell matures & becomes the secretory product

*based on number of cells , histology:a) unicellular cup shaped columnar cells with flat basal nucleus & pale cytoplasm

b) multicellular simple or compound; secretory portion may have tubular invaginations of lining epitheliumor alveolar/acinar w/c are glandular invaginations of the epidermis w/c terminate in flask shaped structures

*based on morphology :

a) simple tubular b) simple branched tubular c) simple coiled tubular d) simple acinar e) simple branched acinar f) compound tubular g) compound acinar h) compound tubuloacinar

SKIN largest organ of the body; composed of an epidermis & underlying dermisFunctions:

protection against injury, bacterial invasion & desiccationregulation of body temperaturereception of continual sensations from the envt.excretion from sweat glandsabsorption of UV radiation

Layers of the skin:epidermis outermost layer; stratified squamous; no blood vessels & few nerve endings; nourished by

diffusion; deeper layers bathed with interstitial fluid from the dermiscells of epidermis:

keratinocytes produce keratinmelanocyets produce melaninlangerhans cells participate in immune responsemerkel cells function for touch sensations

layers of epidermis:statum basale deepest layer stratum spinosumstratum granulosum contain keratohyalinstratum lucidum layer of dead cellsstratum corneum dead dry squamous cell, shed off

dermis tough, elastic, composed of collagenLayers of dermis:

papillary superficial region, contains papilla, capillaries, nerve endingreticular main deeper fibrous layer, consist of collagen & elastic fibers, provide skinstrength, extensibility & elasticity, contains sebaceous gland, sweat gland, fat cells &

blood vessels

ULTRAVIOLET RADIATION (UVR) often called black light is one of many kinds of waves that are placed on theelectronic spectrum. UVR is between visible light and x-rays on the spectrum. It consists of high-frequency wavelengths,invincible to the human eye, ranging from 200 to 400 nanometers. While the most common source of UVR is the sun .

Certain benefits include blood pressure gradually falling for twenty-four hours, and lowered pressure (persisting) for severaldays (WHO, 1979). The harmful effects of UV light outweigh the positive outcomes, though. Health risks arise from chronicand excessive exposure to UVR. It damages the skin w/c can be seen in a sunburn or a tan. The effect of UV rays depends on theseason, time of the day, latitude, and cloud cover (WHO, 1979). Accumulated exposure to the sun can cause skin cancer. UVlight also increases the risks of cataracts and other eye problems, and can subdue the immune system (Strange, 1995). Not allUVR behaves the same way. There is a great difference between long-wavelength UVR and short-wavelength UVR. While


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longer wavelength rays causes tanning, shorter wavelength UVR causes sunburn and skin cancer (Hazen, 1996). As a result of these considerable differences among UV light, UVR is divided into the ff. three bands: UVA (320 400 nm), UVB (290 320nm), and UVC (200 290 nm).

Ultraviolet A Radiation stretching from 320 to 400 nm, is placed beyond the violet portion of the visible spectrum. Shortwavelength UVA is more damaging than long wavelength UVA. Although not much is known about the effects of UVAradiation, it is known that, in general, UVA rays cause the skin to tan. Most researchers believe that UVA rays multiply toharmful effects of UVB radiation or accelerate the growth of existing cancer cells. UVA prematurely wrinides and withers skin,giving it an aged look (Brink, 1996). Although the other two types of ultraviolet radiation cannot, UVA radiation can penetratewindow glasses. The link between UVA and skin cancer is currently being explored.

Ultraviolet B Radiation existing from 290 to 320 nm, is more damaging than UVA, alone causing more than ninety percent of skin cancers including melanomas, most deadly of skin cancers (Trichopoulu, 1996). UBV is located on the lower of the zonesultraviolet radiation absorption band, also known as Huggins bands , and is responsible for most sunburn. Scattering plays animportant role in the damaging effects of UVB radiation, increasing the intensity of sunlight. Scattering is greatest in the shorter wavelengths; therefore, UVB is subject to the most atmospheric scattering (Giese, 1976). UVB radiation is strongest at lowaltitudes and high altitudes. At higher altitudes, the sun is low in the sky, therefore, it takes a longer path through the atmosphereand more of the UVB is absorbed (Parson, 1996). Although UVB rays are of very low intensity compared to UVA radiation.UVB is the most dangerous and detrimental to living things, and more specifically to human beings . While most living things are

protected from UVB radiation by feathers & fur human beings don not have this natural form of defense.The best form of defense against UVB radiation is sunscreen , measured in terms of sun protection factor (SPF). For instance, asunscreen of fifteen confers fifteen times more protection against UVB radiation, studies have not yet proven that they block UVA rays well (Wentzell) major concern of researchers is the depletion of the ozone layer, resulting in increased UVB radiationreaching the Earth. Currently, many UVB rays are prevented fro reaching the Earth, but depletion of the ozone layer would onlymake human more susceptible too burning and cancer. In fact, the ozone layer has thinned by six to seven percent in the midlatitudes of the Northern Hemisphere, which include the United States, since 1979 (Brink, 1996). This increase allows six tofourteen percent more UVB rays through the Earths surface. UVB is the one type of ultraviolet radiation with which we,humans, must be most concerned.

Ultraviolet C Radiation reaching from 200 to 290 nm, does not reach us; it is absorbed by the ozone layer (Marwick, 1995). Itis a misconception that ozone is found at the Earths surface, though. Only nitrogen, oxygen, carbon dioxide, argon, neon,helium, krypton, xenon, hydrogen, methane, and nitrous oxide exist there. Despite this statement, research has shown that athigher levels f the atmosphere between fifteen and thirty-five kilometers, above the Earths surface, ozone is found (Giese, 1976).The existence of oxygen on the Earths surface is the reason an ozone layer exists. Without the ozone layer and its absorption of UVC light, life on Earth would not be possible.

Preventing Sunburn:natural protectionclothingsunscreens

Sunscreening agents:UV absorbing agents para-amino benzoic acid (PABA) in ethanol lotionsUV scattering & blockingsystemic/oral

DEGREES OF BURNS:First Degree Burns minor burn involving only the top of layer of skin. A sunburn is an example of a first degree burn. Thistype of burn is red and hot, but there is no swelling or blistering.Treatment : For first and second degree burns you must begin to minimize the damage quickly. Put the affected area in coolrunning water until the burning feelings leave. This can take longer than 10 minutes. Do not stop this cooling off step too early. If the victim is burnt through the clothing, as in a spill of hot liquid, do not remove the clothing immediately immerse the burntarea in the cool water. Butter, oil, lotions, or creams should not be applied to burns. They will worsen it. Covering the burn withadhesive dressing bandages is also not advisable, burns need to breath.

Second Degree Burns involves the top layer of the skin as well as part of the underneath. The skin is a light red and blistery,somewhat swollen and moist and oozing. The pain is very severe.Treatment : -do-

Third Degree Burns involves all layers of the skin. The burn will destroy the nerves and blood vessels in the skin. There isvery little pain at first. The burn area is white, yellow, black, or cherry red. The skin will be dry and leathery. As the burns healthere will be dense scarring and possible skin grafting.Treatment : For third and fourth degree burns call for emergency medical assistance or take them immediately to the emergencyroom. Do not remove any clothing stuck to the burnt area, cover with a clean cloth.

Fourth Degree Burns goes through all the layers of the skin and down into the muscle and the bone. It looks like a thirddegree burn and does great harm to the body structure. The nerves that are burnt have little pain.


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Treatment : -do-

Table 2. Skin Types

Skin types Skin categories Skin sensitivity

SKIN TYPE I always burn, never tan very sensitive to sunlight

SKIN TYPE II always burn, sometimes tan sensitive to sunlight

SKIN TYPE III sometimes burn, sometimes tan normal sensitivity to sunlight

SKIN TYPE IV sometimes burn, always tan skin is tolerant to sunlight

SKIN TYPE V never burn, always tan skin is brown, very tolerant

SKIN TYPE VI skin is black, extreme tolerance

Table 3. Skin Characteristics

Skincategories Skin color in unexposed area Tanning history

Skin sensitivityvalue

never tans,always burns pale or milky, white alabaster

develops red sunburn, painfulswelling, skin peels 4 - 10

sometimes tans,usually burns very little brown, sometimesfreckles

usually burns, pink or red coloringappears, can gradually develop light

brown tan10 12

usually tans,sometimes

burns

light tan, brown, or olivedistinctly pigmented

rarely burns, moderately rapidtanning response 11 14

always tans,rarely burns brown, dark brown, or black

rarely burns, very rapid tanningresponse 12 16


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Module 4: The Prince and the PeaInstructional Objectives:


1. Describe

Documents

1st Bimonthly - Modules 1-5(1)