Biology Honors Midterm Review

8/3/2019 Biology Honors Midterm Review

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Biology Honors Midterm Review

Scientific Method

The organized way of using evidence to learn about the natural world

The goal of science is to investigate and understand nature. Also, to explain events in nature

and to use those explanations to make useful predictions

Scientists

They make observations using one or more of their senses to gather information

-Qualitative - Can not be easily counted or measured (Odor or texture)

-Quantitated - Can be easily measure (Like objects)

Interpreting Evidence

An observation must be understood to be useful

An inference is a logical interpretation based on proper knowledge and experience

Explaining the Observation

When faced with a problem, scientists may formulate several hypotheses for why it is

happening

A hypothesis is a possible explanation for a set of observations or an answer to a scientific

question

Hypotheses arise from prior knowledge, logical inferences or imaginative guesses

Designing an Experiment

I. State the problem -What are we trying to learn?

II. Form the hypothesis

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III. Set up a controlled experiment - Only one variable should be changed, others remain

constant

IV. Record and analyze your data

V. Draw a conclusion: evaluate the data and state whether it supports or refutes the hypothesis

Characteristics of Life

All living things are:

-Made of cells

-Reproduce

-Based on a genetic code

-Grow and develop

-Obtain and use materials

-Respond to their environment

-Maintain homeostasis

Made of Cells

A cell is a collection of living matter enclosed by a barrier that separates that cell from its

surroundings

-Unicellular - Consists of one cell (Bacteria)

-Multicellular - Consists of many cells (Complex organisms)

Life Processes

Metabolism - All the chemical reactions that occur within the cell of a metabolism.

-Digestion, Synthesis, Hydrolysis

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Respiration - This is not the same as breathing and is sometimes called cellular respiration.

Chemical bond energy stores in nutrients are released for us by cells

-Anaerobic - Fermentation without oxygen

-Aerobic - With oxygen

Synthesis - Involves combing simple substances into complex substances.

-Most common is dehydration: Joins two simple substances by removing water. Amino

acids in your food are used to create protein with this process

Transport - This is not the same as locomotion. This is the movement of materials into and

within a living thing

-IE- Our circulatory system moves oxygen and nutrients into our cells. (Locomotion is

movement, such as plants bending towards the sun or animals moving their bodies)

Regulation - Control and coordination

-Includes communication, like the endocrine and nervous system

Assimilation - The process by which materials are incorporated into a living thing.

-Proteins we ingest are used by our bodies

Nutrition - Obtaining and processing food

-Autotrophs - Make their own food (photosynthesis and chemosynthesis)

-Heterotrophs - Must obtain food

Growth - An increase in either the size or number of cells. All organism grow during at least

one part of their life cycle.

-Organisms also develop which is a change in the appearance of the organisms structure

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Excretion - The removal of all wastes produced by the ells of the body

-We exhale CO2 as a waste product of cellular respiration

-One celled organisms such as ameba excrete wastes through their cell membranes

Reproduction - Process by which organisms produce new organisms

-This is the one process that is not necessary for the individual but is necessary for the

survival of the specie.

-Can be asexual with one parent or sexual with two parents

Homeostasis

When all life functions are maintained.

The process by which living things keep a stable internal environment

Images Under the Microscope

Images under microscope appear upside down and backwards

When viewing under the microscope, move slide in opposite direction to center

Field of Vision

Switch to high power from lower power, the field of vision gets smaller but the detail of the

object gets smaller.

Light

Higher magnification = you need more light

Measure

Use millimeters or micrometers (1 Micrometer = 1,000 millimeters)

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Cells

Cells have been particular structures that perform specific jobs. These cell parts coordinate and

work together just as systems within an organism are coordinated and work together

Cell Theory

This is one of the fundamental concepts of Biology

-All living things are composed of cells

-Cells are the basic units of structure and function in living things

-New cells are produced from living cells

Exceptions to the Theory

Viruses can not reproduce on their own, they must be inside a living thing in order to reproduce

Mitochondria and Chloroplast contain their own DNA and can reproduce

Organelles

Specialized cell structures that are formed from many different molecules and perform specific

jobs

-Cytoplasm - Transports materials

-Mitochondria - Extracts energy from nutrients in a process called cellular respiration

-Ribosome - Protein building

-Lysosome - Contains enzymes

-Cell Membrane - A thin flexible selectively permeable membrane

-Endoplasmic Reticulum - Modifies components of the cell membrane and modifies

some proteins

-Vacuoles - Storage of the cell

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-Nucleus - Information center; the nucleus contains the DNA

Plant Cells

There are two organelles that are found in plant cells but not in animal cells

-Cell Wall - Provides support and structure for the cell

-Chloroplast - Use energy from sunlight to make energy rich food molecules in a process

called photosynthesis

Levels of Organization

Cells are grouped into tissues > organs > organ systems > organism

The body is composed of different kinds of cells grouped in ways that enhance how they

function together

The structures present in single - celled organisms act in a manner similar to the tissues and

systems found in multicellular organisms

Fluid Mosaic Model

The cell membrane regulates what enters and leaves the cell and also provides protection and

support

The core of the cell membrane is a double layered sheet called a lipid bilayer

Embedded within the cell membrane are protein channels that allow certain molecules to enter

the cell

Carbohydrate chains are attached to the outside of the membrane and act for identification

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Diffusion

Diffusion causes substances to move across a membrane but does not require energy

-All cells contain liquid and are surrounded by liquid

-When molecules are in solution they move constantly

-When the concentration of a substance is different in one of these liquids, it moves from

the area of high concentration to low concentration

-Equilibrium is reaches when the concentration is the same both inside and outside of the

cell

Osmosis

The diffusion of water through a permeable membrane

-When the concentration of a substance that can not pass through the membrane is lower

on one side of the membrane, water diffuses through the side of the membrane until

equilibrium is reaches

-Water like other substances move from an area of high to low concentration

Osmotic Pressure

Because cells contain numerous salts, sugars and protein, the concentration of water is usually

lower inside a cell, so water is constantly diffusing into a cell

The extra water pressure creates osmotic pressure

Osmotic pressure can cause a cell to burst if they do not have a way to remove water

Most cells in multicellular organisms do not come in contact with fresh water. So this is not a

problem

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Single celled organisms that live in fresh water have mechanisms to move water out of the cell.

These mechanisms require energy

Facilitated Diffusion

For molecules that can not pass through, the cell membrane can move through a protein

channel

-Different protein channels allow ions, sugars and salts to cross various membranes

-This process is fast and specific but still moves from areas of high to low concentration

and does not require energy from the cell

Active Transport

Moves substances from low areas to high areas of concentration. This process requires the cell

to input energy

-Endocytosis - When the cell folds over to take in large molecules

-Phagocytosis - The cell membrane engulfing food. The membrane pinches off, forming a

vacuole

-Exocytosis - The process where a vacuole fuses with a cell membrane, forcing the

contents out of the cell

Classification

Needs for classification

I. All living things are basically alike in functions

II. There is however a great variety in the ways and means by which different organisms

carry out these functions

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III. In order to study the variety of life in an organized and systematic manner, the different

kinds of organisms are grouped together or classified on the basis of certain common

characteristics or the relationships they share

Classification of organisms are based mainly on similarities of structure

I. Some classification is supplemented by other evidence such as:

A. Fossil record

B. Biochemical date - genetic makeup

C. Behavioral information

D. Embryonic development

E. Cellular structure

II. Modern classification is based on the assumption that all present forms of life development

from earlier forms and have have common ancestors. The grouping of organisms suggest

relationships among them that may be the result of common ancestry

Modern Classification Systems

I. Carolus Linnaeus - Father of modern taxonomy

A. Developed the classification system today

B. Based mainly off of structural similarities

II. Binomial Nomenclature

A. Names are in Latin

B. Italicized with the genus name

III.They are first separated into kingdoms

A. Not all scientists agree on the number

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B. Most used is 5 kingdoms

1. Animal - Multicellular organisms ingest food.

2. Plants - Multicellular organisms that make their own food

3. Fungi - Cells are usually organized into multicellular filaments called hypae, They

reproduce by the means of spores

4. Protists - Mainly one celled plants-like or animal-like organisms. They have distinct

nucleus surrounded by a double membrane

5. Monera - Primitive cells, lacking a nuclear membrane (Prokaryotic)

C. Linnaeus System of Classification

1.Kingdom

2.Phylum

3.Class

4.Order

5.Family

6.Genus

7.Species

Biochemistry

The study of organic compounds

Chemical Bonds

Ionic Bonds - Transfer electrons (Like salt crystals dissolving in water)

Covalent Bonds - Share electrons

Van Der Waals Bonds - Atoms attracted to each other

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Way to remember: King Philip Came

Over For Good Soup/Salad/Other words

that start with S


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Water

Has 2 H+ molecules and one O-

Polar - Has 2 different charges

Adhesion - Sticks to other things (Like rain on a window)

Cohesion - Sticks to itself (Like a puddle)

pH

Measure of H+ (Positive Hydrogen atoms in a solution)

Scale of 1-14

1 - Very acidic (Lots of H+)

7 - Neutral (Pure Water)

14 - Very little H+ (A Base)

Buffers - Control pH to prevent sharp changes (Maintains homeostasis)

Organic - Has carbon and hydrogen ( Like C6H12O6 )

Carbohydrates - Main source of energy for living things

Subunits - Sugar (Saccharide)

Inorganic - No carbon (Like H2O)

Monomer - One, small unit

Polymer - Big unit, from small units

Carbohydrates

Monosaccharide - 1 Sugar (Glucose)

Disaccharide - 2 Sugars (Lactose)

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Polysaccharide- Many Sugars (Starch)

Lipids (Fats)

Store energy

Made of mostly carbon and hydrogen

Subunits - 1 glycerol and 3 fatty acids

Saturated - Max # of hyrdogens; no double bonds in the molecule

Unsaturated - 1 Carbon double bonded to another

Polyunsaturated - More than 2 double bonds (Missing 4 or more Hs)

Protein

Regulate cell processes and control rate of reactions inside cells -Enzymes

Made of nitrogen, carbon, hydrogen, and oxygen

Subunit - Only 20 different amino acids

DNA tells amino acids what order to get in to make certain proteins

Enzyme

Made of protein

End in Ase, like Lactase

Involved in all chemical reactions

They are catalysts - Increase rates (speed) of reactions by lowering activation energy

Substrate/Reaction = Product

Fits into the enzyme at the active site

The fit is specific and must be exact for the reaction to occur

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Enzyme substrate complex - When theyre together, the enzyme does not change shape after a

reaction and can be re-used over and over

Enzyme Reactions are affected by:

Temperature - Too high/Too low = denatures enzyme

pH - Too high/Too low = denatures enzyme

Concentration of Substrate -

More substrate = Higher concentration = Faster reactions

Fewer substrate = Lower concentration = Slower reactions

C6H12O6 + C6H12O6 X C12H24O11 + H2O

Reactants Products

X=Enzyme

Nucleic Acid

Store and Transmit hereditary information

DNA and RNA

Made of carbon, phosphate and nitrogen

Subunit - Nucleotides

Nucleic Acid - Carbon, hydrogen, nitrogen, oxygen, phosphates

Lipids - Carbon and hydrogen

Proteins - Hydrogen, Oxygen, Carbon and Nitrogen

Carbohydrates - Hydrogen, Oxygen, Nitrogen, Carbon

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Leaf Structure

The structure of a leaf is optimized for absorbing light and carrying out photosynthesis

To collect sunlight, most leaves have thin flattened sections called blades.

Leaves are covered on the top and bottom by an epidermis.

The leaf epidermis is sometimes covered with a cuticle

The epidermis and cuticle protect leaves from water loss

Transpiration

The loss of water from a plant through its leaves. Water is lost in ways by being replaced by

water drawn into the leaf through the Xylem

Xylem - Tubes through which water moves from the roots to the leaves

Plants keep their stomata open just enough to allow photosynthesis to take place, but not so

much that they lose an excessive amount of water

-Stomata - Are pore like openings in the underside of the leaf that allow CO2 and Oxygen

to diffuse in and out of the cell

-Each stoma consists of two guard cells that control the opening and closing of

stomata by responding to changes in water pressure

-When the pressure is hugh, the outer walls of the cells are forced into a curved

shape and the stoma is opened. Wen pressure is low, the guard cells are not curved

and the stoma closes

Biochemical processes are necessary to maintain homeostasis in living things. Life is

dependent upon the availability of an energy source and raw materials that are used in the basic

enzyme controlling biochemical processes of living organisms

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-The energy for life comes from primarily from the sun. Photosynthesis provides a vital

connection between the sun and the energy needs of living systems

Plant cells and some one celled creatures contain chloroplasts (The site of photosynthesis)

-Photosynthesis uses solar energy to combine the inorganic molecules (CO2 and H20) into

energy-rich organic compounds (Glucose - C6H12O6)

-Oxygen is released into the environment as a result of this process

( http://www.youtube.com/watch?v=aupr9qT2qgc ) Song for Photosynthesis

6CO2 + 6H2O -> C6H12O6 + 6CO2

Carbon Dioxide + Water = Sugar and Oxygen

In addition to Water and Carbon Dioxide, photosynthesis requires light and chlorophyll, a

molecule found in chloroplast

The Reactions of Photosynthesis

The process of photosynthesis includes the light dependent reactions as well as the Calvin

cycle

Calvin Cycle - Light Independent Reactions

The light dependent reactions produce oxygen gas and convert ADP and NADP into ATP and

NADPH

The light dependent reactions occur in different areas of the thylakoid called Photosystem I and

Photosystem II

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The Calvin Cycle uses ATP and NADPH from the light-dependent reactions to produce high

energy sugars.

The chemical energy stored in the bonds or organic compounds can be used as a source of

energy for life processes. This energy may be released during the process of cellular respiration

C6H12O6 -> H2O + ATP

Sugar + Oxygen = Carbon Dioxide + Water + ATP

-ATP - Adenosine Triphosphate

This energy is temporarily stored in ATP molecules

This energy from ATP is used by the organism to obtain, transform, and transport materials and

to eliminate wastes.

In organisms that use oxygen, carbon dioxide and water are released and ATP is produced.

Cellular respiration is concluded in the mitochondria

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In organisms that do not use oxygen or if oxygen is not available, less ATP is produced

With Aerobic - 36 ATP is used

With Anaerobic - 6 ATP

The Reactions

Glycolysis - The process in which one molecule of glucose is broken in half, producing two

molecules of pyruvic avid

When oxygen is not present, a different pathway follows glycolysis. Glycolysis and the

pathway are called fermentation, because fermentation does not require oxygen, it is anaerobic

respiration

The two main types of fermentation are alcohol fermentation and lactic acid fermentation

Yeast and a few micro-organisms perform alcohol fermentation

Produces Carbon Dioxide and Alcohol

Pyruvic Acid -> Alcohol + CO2 + ATP

Lactic Acid fermentation takes place in cells during exercise when the body cannot supply

enough oxygen to the muscles. The buildup of lactic acid causes a painful burning

sensation (This is why muscles are sore after exercise)

Pyruvic Acid -> Lactic Acid + CO2 + ATP

The energy to make ATP comes from Catabolic Reactions that are Exergonic

(Exergonic = Chemical reactions that release energy)

(Catabolic Reactions- Breakdown of more complex organic molecules into

simpler substances)

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Respiration and Photosynthesis

Different Similar Different

Uses: CO2

Uses: H20

Uses: Sunlight

Produces: Glucose

Produces: O2

Occurs in: Chloroplast

Aerobic: (Oxygen + Glucose -> Carbon Dioxide + Water + Energy)

Digestive System

Made up of digestive tract and accessory glands

15 feet/9 Meters long

Purpose - To acquire energy and nutrients out of the food we eat

The pathway that food travels through the digestive system:

-Mouth

-Esophagus

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ses: Oxygen

ses: Glucose

oduces: CO2

oduces: H2O

oduces: ATP

ccurs in: Mitochondria

< Respiration >

Occurs in Cells

Chemical Reactions

Needs Enzymes

Involves Energy

< Photosynthesis >

lcohol Fermentation : C6H12O6 -> Alcohol + CO2 + ATP

actic Acid Fermentation: Lactic Acid + ATP

erobic Cellular Respiration: 6O2 + C6H12O6 -> 6CO2 + 6H2O +AT


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-Stomach

-Small Intestine

-Large Intestine

-Rectum

-Anus

Accessory Glands

Exocrine glands that secrete digestive liquids through ducts into the digestive system

Salivary Glands

Pancreas

ALiver

Mouth and Salivary Glands

Teeth mechanically break up food

Breaks down food into smaller pieces to increase the surface area so that it can be digested

easier

Salivary Glands - Produce saliva

Made up of mostly water which moistens food, making it easier to swallow

Ptyalin and Amylase are digestive enzymes in saliva which begin the breakdown of simple

sugars.

Esophagus

A gullet or muscular tube

Peristalsis - Waves of muscle contraction in the throat that push food through the digestive tract

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-Takes food from the throat and pushes it down the neck and into the stomach (Takes

5-10 seconds

Stomach

The thick muscles in the stomach wall contract to mash the food up

Chemical digestion of protein begins here

Gastric glands secrete gastric juice which contain digestive enzymes, acids, and mucus

Pepsin - Begins protein digestion

Hydrochloric Acid - Produces acidic environment in stomach so digestive enzymes can

work better

Mucus - Protects the stomach wall from acid

Digestion here takes about 2-6 hours

Small Intestine

6 Meters long

Final digestion and nutrient absorption occurs here over a 5-6 hour period

In the beginning, mostly digestion is occurring whereas in the end, mostly absorption is

occurring

Villi - Small fingerlike projections that increase surface area of the small intestine which

maximizes absorption/diffusion

-Capillaries - Simple sugars, amino acids, vitamins and minerals are absorbed into the

bloodstream here

-Lacteal - Fatty acids and glycerol are absorbed into these tiny lymphatic vessels

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Pancreas

Produces a couple of digestive enzymes that chemically digest or breakdown proteins,

carbohydrates, fats, and nucleic acids in the small intestine

Chemical Digestion:

-Protein -> Amino Acids

-Carbohydrates -> Simple Sugars

-Lipids -> Fatty Acids

-Nucleic Acids -> Nucleotides

Liver

Among many other functions in the body, it produces bile which doesnt contain any digestive

enzymes

Bile is stored in the gall bladder

Bile emulsifies the fat into smaller globules

(Mechanical Digestion), Which aids in the absorption of fats in the small intestine

Large Intestine

Any useful substances in the leftovers, such as spare water and body minerals are absorbed

through the walls of the large intestine, back into the blood

Usually takes about 12-24 hours to move through the large intestine

The remains are formed into brown, semi-solid feces, ready to be removed from the body

Over 7 liters of water are released into the digestive tract with secretions throughout a day (this

is much more than the average person drinks). 90% of this water is recovered in the small and

large intestines

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Rectum and Anus

Feces are stored in the rectum until they can be eliminated/egested

These are finally pushed through a ring of muscles (the anus) and out of the body

Gall Stones

Deposits of bile that became hardened stone like structures and can be surgically removed

Disorders of the Digestive System

Heart Burn

-Painful burning sensation in the center of the chest

-Caused when stomach acid moves out of the stomach and into the esophagus

-Happens when you drink or over eat

Peptic Ulcer

-Holes in the wall o the stomach caused by acid

-For many years, people thought this was caused by stress and spicy food

-Caused by Helicobacter Pylori Bacteria

-Doctors can cure 90% of ulcers with antibiotics

Appendicitis

-Inflammation of the appendix

-Located below colon/large intestine

-No function in humans

Diarrhea

-When not enough water is absorbed by the large intestine

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-A lot of salts and water can be life threatening

-Can be caused by contaminated water

-Leading cause of childhood death in under-developed countries

The Human Circulatory System

Consists of:

The heart

A series of blood vessels and the blood that flows through them

The Heart

Located near the center of your chest and is composed entirely of muscle

The size of a clenched fist and contracts roughly 72 times a minute pimping 70 milliliters of

blood each time

Parts of the Heart

Pericardium - Protective sac of tissue

Myocardium - A thick layer of muscle in the walls

Septum - Divides the left side and the right side of the heart

Prevents oxygen rich blood from mixing with oxygen poor blood

Upper chamber which receives blood is the Atrium

Lower chamber which pumps blood out is the Ventricle

There are two atriums and two ventricles: A total of four chambers

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Heartbeat

Contractions begin in a small group of cardiac muscle cells

Located in the right atrium called the sinoatrial node

Because these cells set the pace for the whole heart, they are also known as pacemakers

Circulation

Blood flows through the lungs through the pulmonary artery, where it picks up oxygen and

returns through the pulmonary vein

Blood then enters through the left atrium and is pumped to the left ventricle, then through the

aorta to the body

Oxygen rich blood flows to the left side of the heart and is pumped to the body (Systemic

Circulation)

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Blood that returns to the right side of the heart is oxygen poor because the cells of the body

have absorbed so much of the oxygen and are loaded with CO2 (both types of blood are shades

of red)

Blood Vessels

Arteries - Large vessels that carry blood away from the heart, except for the pulmonary artery,

they always carry oxygen rich blood

-They have thick walls to help them withstand pressure

-Exerted when the heart contracts and pushed through them

Capillaries - Smallest vessel (the walls are only once cell thick)

-Blood must pass through in single file and the bring the nutrients to the tissues and

absorb CO2 and other wastes

Veins - Returns blood to the heart and the walls contain connective tissue and muscle like

arteries

-They contain one way valves that keep the blood flowing toward the heart

-Many are located near skeletal muscles so when these muscles contract, blood is forced

through the veins

Blood

Blood is made 45% of cells

Suspended in the other 55%, a straw colored fluid called plasma

Plasma is 90% water and 10% dissolved gases, salts, nutrients, enzymes, hormones, waste

products, and proteins called plasma proteins

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Red Blood Cells

Transport oxygen and get their color from hemoglobin

The iron containing protein that binds to oxygen in the lungs and transports it to the tissues

White Blood Cells and Platelets

White blood cells attack foreign substances or organisms

Blood clotting is made possible by plasma and proteins and cell fragments called platelets

Blood Types

A, B, AB, O

Blood can be given to individuals with the same blood type and all blood types can receive O

Blood Pressure

When the heart contracts, it produces a wave of fluid pressure in the arteries

The pressure the blood exerts on the artery walls is known as blood pressure

Blood pressure decreases when the heart relaxes but the system remains under pressure

Measuring Blood Pressure

Medical workers can measure blood pressure with a cuff placed on the arm

An average adults blood pressure is 120/80

First number is the systolic pressure: the force in the arteries when the ventricles contract

Second number is the diastolic pressure: the force in the arteries when the ventricles relax

Disorders of the Circulatory System

Arteriosclerosis - Fatty acids known as plaque build up on the walls of the arteries

If the deposits get too big they obstruct blood and can increase blood pressure

The plaque buildup also increases risk of blood clots

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High Blood Pressure/Hypertension - Forces the heart to work harder which may weaken or

damage the heart muscle and blood vessels (Increases risk for heart attack and stroke)

Heart Attack - When the arteriosclerosis blocks one of the arteries bringing blood to the heart

Part of the heart muscle begins to die from lack of oxygen

Symptoms include nausea, shortness of breath, and severe crushing chest pain

Stroke - Blood clots break free and stuck in one of the blood vessels leading to the brain

Brain cells die from lack of oxygen

Can also occur when a weakened blood vessel in the brain bursts

Prevention - These disorders are easier to prevent than cure

Exercise, weight control, sensible diet and not smoking seem to be the best ways to keep

the heart healthy

Lymphatic System

A network of vessels called the lymphatic system

Collects the fluid that is lost by the blood and returns it to the circulatory system

Along the length of the lymph vessels are small enlargements called lymph nodes

They act as filters that trap bacteria and other microorganisms; they can become enlarged

as a result

Respiratory System

Two meanings: when glucose and oxygen are converted into CO2, water and ATP into the

mitochondria

Oxygen and CO2 are exchanged between cells, the blood and air in the lungs

Nose, pharynx, larynx, trachea, bronchi and lungs

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Nose

Filters dust particles in the air

Hairs lining the entrance to the nasal cavity traps large dust particles

Mucus, produced by cells lining the system, moistens the air and traps inhaled particles

Cilia sweeps trapped particles and mucus away from the pharynx

The mucus is either spit out or swallowed

Airflow

Air moves from the nose to a tube at the back of the throat called the pharynx

This is the passageway for both air and food

When food is swallowed, a piece of cartilage called the epiglottis covers the trachea

-Trachea - Tube from pharynx

-Vocal Cords - Two highly elastic folds of tissue in the larynx. When the muscles pull the

chords together, the air moving between the folds causes the chords to vibrate

Air moves the trachea and enters two large passageways n the chest cavity called the bronchi

(Each bronchus leads to the lungs)

In each lung, the large bronchi subdivides into smaller bronchi which lead to even smaller

bronchi called bronchioles

The bronchi and bronchioles are surrounded by smooth muscles that regulate the size fo the

passageways

Alveoli - Tiny air sacs at the end of the bronchioles and are grouped together like

grapes. A delicate network of capillaries surrounds each alveoli

This is where the exchange of oxygen and CO2 happen within the blood

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Gas Exchange

Oxygen diffuses through the inner surface of the alveoli and through the capillary to the blood

CO2 diffuses in the opposite direction

Very efficient process: inhaled air is 21% oxygen and .04 CO2

-Exhaled air is 15% oxygen and 4% CO2

Breathing

The movement of air into and out of the lungs

Lungs have no muscles attached to them so the large flat muscle at the bottom of the chest

cavity is called the diaphragm

Because the cavity is sealed, this causes a vacuum and atmospheric pressure causes air to rush

to the lungs

The system works because the cavity is sealed and if it is punctured, then it is very difficult to

breathe

Breathing is controlled by the amount of CO2 in the blood, not oxygen

Diseases

Asthma - Constriction of the bronchioles caused by allergens or exercise

Emphysema - Loss of elasticity in the lungs

Bronchitis - Bronchi are swollen and filled with mucus

Lung Cancer - Particular deadly because it easily spreads to other locations (It metastasizes or

spreads), mostly caused by smoking or asbestos

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Excretion

Metabolic waste is ousted

-CO2 is a waste of cellular respiration

-Water is a waste of cellular respiration and dehydration synthesis

-Mineral salts are produced by many processes

-Nitrogenous wastes

-Result of metabolism of proteins and when proteins are used in cellular

respiration

Ammonia: Very toxic

Urea: Less toxic

Uric Acid: Generally non-toxic

Results

Toxic materials are released by animals

Toxic materials are sealed and stored in the vacuoles of plants

Non-toxic wastes are retained, released, or recycled in other metabolic activities

Human Excretory System

Two kidneys on either side of the spinal column near the lower back

Two ureter tubes that leave each kidney and cary urine to the bladder

-Bladder - Where urine is stored

-Urethra - Is the tube in which urine travels to leave the body

Kidney

Made of two parts

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-Inner: The renal medulla

-Outer: The renal cortex

Functional unit of the kidney is called the nephron (1 million nephrons in each kidney)

Kidney Function

Waste containing blood enters the kidney through the renal artery

Blood travels through the kidney and urea and other wastes & water are filtered out as urea

The cleaned filtered blood is returned to circulation through the renal vein

Blood Purification

A complex mechanism that involves three distinct processes

I. Filtration

II. Reabsorption

III. Secretion

Filtration

Occurs in the Glomerulus

Diffusion causes substances to leave the blood and enter the Bowmans Capsule

Water, salt, glucose, amino acids and urea are filtered

Proteins and blood cells remain in the the blood because they are too large to diffuse

Reabsorption

The kidneys play an important role in homeostasis; they regulate blood volume, water content,

blood pH, and remove wastes from the body

If anything goes wrong, serious medical problems can ensue; humans can only live with one

kidney

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If both kidneys fail there are two options:

Transplant from healthy, compatible donor

Dialysis blood is removed and pumped through a machine that does the work of a nephron

(Expensive and time consuming - 3 times a week for several hours)

Immune System

Homeostasis - An organisms homeostasis is constantly threatened (Failure to respond can

result in disease or death)

Agents of Disease: V

-Viruses - Common Cold, Chicken Pox, Influenza

-Bacteria - Tetanus, Meningitis, Strep Throat

-Fungi - Athletes foot, ringworm

-Parasites - Protists - Malaria, African Sleeping Sickness

- Worms - Tapeworm

Factors of Disease

Many show up right away or not show up for many years

Inheritance, Toxic Substance, Poor Nutrition, Organ Malfunction, Personal Behavior

Person-to-Person (Through coughing, sneezing and physical contact or sexual

transmission)

Contaminated food or water

Exposure to an infected animals (Vectors- Insects tat spread disease via bite)

First Line of Defense

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A nonspecific response like skin which is the most important nonspecific response. This is the

barrier that keeps pathogens out of the body (even a small cut can become infected)

Pathogens can enter through the mouth and nose

Mucus in your nose and throat trap viruses and bacteria

Cilia push them away from lungs

Stomach acid and digestive enzymes destroys pathogens

Body secretions including mucus, saliva. sweat and tears contain lysozyme (breaks down

cell walls of bacteria)

Second Line of Defense

Inflammatory response (When pathogens enter the body and release toxins)

Blood vessels near the infection site grow larger and white blood cells leak into the infected

area

-Phagocytes (Macrophages) - White blood cells that engulf and destroy pathogens

-B Cells - Produce antibodies

-Killer T Cells - Attach to and kill infected cels

-Memory B and T Cells - Remain after an infection, ready to kill the pathogen before you

get sick if you are ever exposed again

Fever

The immune system releases chemicals that raise the body temperature

Many pathogens can only survive in a narrow temperature range

This slows or stops their growth and speeds up metabolism in the body to repair damaged

cells

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Specific Defenses

If a pathogen gets past the nonspecific defense, the body starts a defense called the immune

response.

The substance that triggers this response is an antigen

-A carbohydrate, lipid or protein on the outside of the pathogen that triggers the immune

response

Humoral Response

Carried out by B Lymphocytes (B Cells)

They produce antibodies

-A protein that helps destroy pathogens and are Y shaped and have identical binding sites

-Antibodies attach to pathogens and mark them for phagocytes and other white blood

cells (Keeps them from entering other cells)

Antibody Production

Specific for each pathogen; B cells each create a different antibody

When infected with a pathogen, the B cell that produces and makes plasma cells, also produces

the specific antibody needed to destroy the pathogen

T Lymphocytes (T Cells) Assist the body

Cell Mediated Immunity

Body cells infected with a pathogen must also be destroyed by T Cells

Organ Transplant Rejection

Killer T cells cause problems during organ transplants. They see the new organ as foreign

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They damage or destroy transplanted organs this is called rejection. To prevent rejection

transplant patients are given drugs to suppress the immune system. This leaves the patients

open to other infections.

Permanent Immunity

Once the body has been exposed to a pathogen, memory B and T cells remain. They are

capable of producing the specific antibody to the pathogen before you ever get sick

Active Immunity

1. Once the body has been exposed to a pathogen memory B cells and T cells remain. They

are capable of producing the specific antibody to the pathogen before you ever get sick.

This is why you can only get certain diseases once in a lifetime

2. Injection of weakened or dead forms of a pathogen is called vaccination. Vaccines cause

the body to produce memory B and T cells without having been infected with the disease

Passive Immunity

1. Travelers are sometimes injected with antibodies produced in animals to give them

protection from certain disease

2. Antibodies can be passed from mother to child through the placenta and through breast

milk

Disorders

1. Allergies happen when an allergen attaches to a type of immune cell called a mast cell

which releases histamine. Histamine causes the sneezing, runny eyes and nose associated

with an allergy. Antihistamines are drugs that counteract histamine.

2. The immune system needs to recognize your own tissues and cells as self in order to

work effectively. When the body makes a mistake and attacks cells of the body it is an

autoimmune disease

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3. Acquired Immune Deficiency Syndrome or AIDS happens when one is infected with the

Human Immunodeficiency Virus or HIV. The HIV replicates in helper T cells which

destroys them. This makes the immune system unable to fight off other diseases

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Documents

Biology Honors Midterm Review