Anatomy & Physiology Lecture #1 - Introduction Fall 2009

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