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Anatomy & Physiology
Lecture #1 - Introduction
Fall 2009
Overview
• Anatomy & Physiology Subdivisions
• Requirements of Life & Survival Needs
• Homeostasis
• Cell Transport
• Biochemistry & Metabolism
Definitions
• Anatomy - the structure of body parts and their relationships to one another
• Physiology - the function of the body
Anatomy Subdivisions
• Gross Anatomy– Regional Anatomy
– Systemic Anatomy
– Surface Anatomy
Anatomy Subdivisions
• Microscopic Anatomy– Cytology
– Histology
Anatomy Subdivisions
• Developmental Anatomy
Physiology Subdivisions
• Most subdivisions focus on the operation of specific organ systems
• Disease states can be thought of physiology gone wrong
Physiology SubdivisionsLevels of Organization
• Simple to Complex– Chemical Level
– Cellular Level• Four large groups of cells in the body
• Activities of cells fall into two categories
Physiology SubdivisionsLevels of Organization
• Simple to Complex– Tissue Level
– Organ Level
Physiology SubdivisionsLevels of Organization
• Simple to Complex– Organ Systems
– Organismal Level
Requirements of Life
• Maintain Boundaries– Single Cell– Humans
• Movement
• Responsiveness
Requirements of Life
• Digestion
• Metabolism– Catabolism– Anabolism– Cellular Respiration
• Excretion
Survival Needs
• Nutrients
• Oxygen
Requirements of Life
• Reproduction
• Growth
Survival Needs• Survival Needs
– Water• 60-80% of the body by weight
• Is the base for body secretions and excretions
• Obtained from ingested food and liquids
• Lost from evaporation and excretion
• Divided into– Intracellular– Interstitial– Plasma
Survival Needs
• Maintain normal body temperature
• Atomospheric Pressure - the force that air exerts on the surface of the body
Homeostasis
The ability of the body to maintain relatively stable internal conditions even though the
outside world changes; indicates a dynamic state of equilibrium
Homeostatic Control Mechanisms
• Communication is essential to maintain homeostasis
• Communication signals in three categories:
– Endocrine– Paracrine– Autocrine
ICF ISF plasma organs
external environment
internal environment
Homeostatic Control Mechanisms
• All homeostatic control mechanisms have at least three interdependent components
Homestatic Control Components
• Receptor
• Control center
• Effector
To Identify a Homestatic System
• Identify the internal environmental variable.
• Establish the “set point” value for that variable.
• Identify the inputs and outputs affecting the variable.
• Examine the balance between the inputs and outputs. • Determine how the body monitors/senses the variable.
• Identify effectors that restore the variable to its set point.
Negative Feedback
Body temperature rises above 37.2 C
Receptors: Information comes from sensors in the skin and hypothalamus
Hypothalamus targets two different effectors
Effectors
1) Muscle tissue in the walls of blood vessels dilate
2) Sweat glands increase activity
Heat Loss Decreases the Body Temperature to Acceptable Levels, Hypothallamus is turned off
Afferent Nerves
Efferent Nerves
Positive Feedback
Uterus is Distorted by the growing fetus and uterine oxytocin levels increase
Endocrine Center of the Brain
Effectors
1) Increased Oxytocin Release leads to increased contraction of the uterine wall
Contraction and further distortion of the uterus
Afferent Nerves
Efferent Nerves
How do things get in and out of cells?
Overcoming the Cell Barrier
• The cell membrane is a barrier, but: – nutrients must get in– products and wastes must get out
Permeability
• Permeability determines what moves in and out of a cell:
• A membrane that: – lets nothing in or out is impermeable– lets anything pass is freely permeable– restricts movement is selectively permeable
Selective Permeability
• Cell membrane is selectively permeable:– allows some materials to move freely– restricts other materials
Restricted Materials
• Selective permeability restricts materials based on:– size– electrical charge– molecular shape– lipid solubility
Transport
• Transport through a cell membrane can be:– active– passive
3 Categories of Transport
• Diffusion & Osmosis
• Carrier-mediated transport
• Vesicular transport
Concentration Gradient
• Concentration is the amount of solute in a solvent
• Concentration gradient:
Diffusion
• Diffusion: – molecules mix randomly
– solute spreads through solvent
Factors Affecting Diffusion Rates
• Distance
• Molecule size:
• Temperature:
Factors Affecting Diffusion Rates
• Gradient size:
• Electrical forces:
Diffusion and the Cell Membrane
Figure 3–15
• Diffusion can be simple or channel-mediated
Simple Diffusion
• Materials which diffuse through cell membrane:– lipid-soluble compounds
– dissolved gases
Channel-Mediated Diffusion
• Materials which pass through transmembrane proteins (channels):– are water soluble compounds
– are ions
Factors in Channel-Mediated Diffusion
• Passage depends on:– size– charge– interaction with the channel
Osmosis
Figure 3–16
• Osmosis is the diffusion of water across the cell membrane
How Osmosis Works
• More solute molecules, lower concentration of water molecules
• Membrane must be freely permeable to water, selectively permeable to solutes
Osmosis Water Movement
• Water molecules diffuse across membrane toward solution with more solutes
• Volume increases on the side with more solutes
Osmotic Pressure
• Is the force of a concentration gradient of water
• Equals the force needed to block osmosis
Tonicity
• The osmotic effect of a solute on a cell: – 2 fluids may have equal
osmolarity, but different tonicity
Figure 3–17a
Isotonic Solutions
• A solution that does not cause osmotic flow of water in or out of a cell
• iso = same, tonos = tension
Hypotonic Solutions
• hypo = below
• Has less solutes
• Loses water through osmosis
Cells and Hypotonic Solutions
• A cell in a hypotonic solution:– gains water– ruptures
Figure 3–17b
Hypertonic Solutions
• hyper = above
• Has more solutes
• Gains water by osmosis
Cells and Hypertonic Solutions
• A cell in a hypertonic solution:– loses water
– shrinks
Figure 3–17c
Special Transport Mechanisms
Carrier-Mediated Transport
• Carrier-mediated transport of ions and organic substrates:– facilitated diffusion – active transport
Characteristics of Carrier-Mediated Transport
• Specificity:
• Saturation limits:
• Regulation:
Cotransport
• 2 substances move in the same direction at the same time
Countertransport
• 1 substance moves in while another moves out
Facilitated Diffusion
• Passive
• Carrier mediated
Figure 3–18
How Facilitated Diffusion Works
• Carrier proteins transport molecules too large to fit through channel proteins (glucose, amino acids):
Active Transport
Sodium-Potassium Exchange Pump
Figure 3–19
Sodium-Potassium Exchange Pump
• Active transport, carrier mediated:– sodium ions (Na+) out, potassium ions (K+) in
– 1 ATP moves 3 Na+
Secondary Active Transport
Figure 3–20
• Na+ concentration gradient drives glucose transport
• ATP energy pumps Na+ back out
Transport Vesicles
• Also called bulk transport
• Vesicles: – endocytosis (endo = into)
– active transport using ATP:
– exocytosis (exo = out of)
Receptor-Mediated Endocytosis
Figure 3–21
Receptor-Mediated Endocytosis
• Receptors (glycoproteins) bind target molecules (ligands)
• Coated vesicle (endosome) carries ligands and receptors into the cell
Figure 3–22a
Pinocytosis• Pinocytosis (cell drinking)
Phagocytosis
• Phagocytosis (cell eating)
Figure 3–22b
Figure 3–7b
Exocytosis
• Is the reverse of endocytosis
Summary
Table 3–3
• The 7 methods of transport
Biochemistry & Metabolism
Organic Molecules
• Always contain carbon and hydrogen
• Many contain long chains of covalently linked carbon
• Many are soluble in water
• Four Major Classes
Carbohydrates
• Contains carbon, hydrogen and oxygen
• Provide a ready, easily used source of cellular fuel
• Classes– Monosaccharide
– Disaccharide
– Polysaccharide
Figure 3.40
Figure 3.41
Figure 3.44
Figure 3.45
Figure 3.46
Figure 3.47
Lipids
• Contain carbon, hydrogen and oxygen
• Purpose– Form essential cellular components– Energy reserves
• Account for 10-12% of our total body weight
Lipids (Continued)• 5 classes
– Fatty acids• Saturated
• Unsaturated
– Eicosanoids• Prostaglandins
• Leukotrines
http://www.biology.lsu.edu/introbio/Link2/fatty%20acids.gif
Lipids (Continued)• 5 classes
– Glycerides (Neutral Fats)
– Steroids
http://www.uic.edu/classes/bios/bios100/lectf03am/steroid.jpg
Types of Steroids
• Cholesterol:
• Estrogens and testosterone:
• Corticosteroids and calcitrol:
• Bile salts:
Lipids (Continued)• 5 classes
– Phospholipids and Glycolipids
http://biology.clc.uc.edu/graphics/bio104/membrane.jpg
Figure 3.48
Figure 3.49
Protein• 100,000 kinds
• 10-30% of total body weight
• Most are macromolecules
Protein Functions
• 7 major protein functions:– Support:
– Movement:
– Transport:
Protein Functions
– Buffering:
– Metabolic regulation:
– Coordination and control:
– Defense:
Structure of Proteins• Consist of long chains of
amino acids
• Joined by peptide bonds
http://ffden-2.phys.uaf.edu/211.fall2000.web.projects/Danielle%20Arnold/Figure1.jpg
Peptides
Figure 2–19
Figure 2–20a
Primary Structure
• Polypeptide:
Secondary Structure
Figure 2–20b
• Hydrogen bonds form spirals or pleats
Figure 2–20c
Tertiary Structure
• Secondary structure folds into a unique shape
Quaternary Structure
Figure 2–20d
• Final protein shape:
Shape and Function
• Protein function is based on shape
• Shape is based on sequence of amino acids
• Denaturation:
Specific Types of Protein• Fibrous
– Extended and strand like
http://www.wellesley.edu/Chemistry/chem227/structproteins/collagen.gif
Specific Types of Protein• Globular
– Compact, spherical proteins hat have at least a tertiary structure
– Water soluble
– Include • Chaperone
• Enzymes
Protein Combinations
• Glycoproteins: – large protein + small carbohydrate
• Proteoglycans: – large polysaccharides + polypeptides
Figure 3.48
Figure 3.50
Figure 3.51
Figure 3.52
Nucleic Acids
• Long chains of nucleotides form RNA and DNA
Figure 2–23
RNA and DNA
• RNA:
• DNA:
Deoxyribonucleic Acid (DNA)
• Determines inherited characteristics
• Directs protein synthesis
• Controls enzyme production
• Controls metabolism
Ribonucleic Acid (RNA)
• Codes intermediate steps in protein synthesis
Important
• DNA in the cell nucleus contains the information needed to construct all of the proteins in the body
Nucleotides
• Are the building blocks of DNA
• Have 3 molecular parts: – sugar (deoxyribose)– phosphate group– nitrogenous base (A, G, T, C)
The Bases
Figure 2–22b, c
Complementary Bases
• Complementary base pairs:– purines pair with pyrimidines:
• DNA:
• RNA:
Forms of RNA
• messenger RNA (mRNA)
• transfer RNA (tRNA)
• ribosomal RNA (rRNA)
ADP and ATP
• adenosine diphosphate (ADP):
• adenosine triphosphate (ATP):
Phosphorylation
• Adding a phosphate group to ADP with a high-energy bond to form the high-energy compound ATP
• ATPase: – the enzyme that catalyzes phophorylation
Figure 2–24
The Energy Molecule
• Chemical energy stored in phosphate bonds
Compounds Important to Physiology
Table 2–8