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Unformatted text preview: Chapter 1 The Study of Body Function (p 4 10) Physiology
a Study of biological functions of the body From cell tissue organ system Ultimate objective of physiological research is therefore to understand the normal functions of cells, organs and systems Homeostasis
a Maintaining constancy of internal environment Walter Cannon (1871-1945) Dynamic constancy Within a certain normal range a a Maintained by negative feedback loops Regulatory mechanisms: Intrinsic: Within organ being regulated Extrinsic: Outside of organ, such as nervous or hormonal systems Negative feedback inhibition Feedback Loops
a The loops Sensor detects deviation from set point Integrating center: CNS or endocrine glands Determines the response Effector: Muscles or glands Produces the response a Negative feedback Common regulatory mechanism for maintenance of homeostasis Defends the set point reverses the deviation produces change in opposite direction Example insulin and blood sugar Action of effectors amplifies the changes Is in same direction as change Example trypsinogen and trypsin a Positive feedback Primary Tissues
a The body composed of 4 different primary tissues: Muscle, nervous, epithelial, connective tissues Epithelial tissues Connective tissues Cells that form membranes Provide barrier between external and internal environments Large amounts of extracellular material in the spaces between connective tissue cells Examples blood, bone, cartilage a a Organs: Composed of at least two primary tissues Organs that are located in different regions of the body and perform related functions Systems: Chapter 2 Chemical Composition of the Body (p 27 29) Water as a Polar Solvent
a a Water is a polar solvent and tends to interact better with polar (hydrophilic) molecules Amino acids, proteins, carbohydrates, and nucleotides are highly polar and ionized so that they are soluble in water (hydrophilic) Hydrophobic (Lipophilic) Substances
a The bulk of any lipid molecule is non-polar Containing long hydrocarbon chains a Lipids are soluble in nonpolar solvents (lipophilic) such as ether and benzene but are insoluble in water (hydrophobic) Amphipathic Molecules
a Contain both polar (hydrophilic) head group and hydrophobic tail group in their structures a Soap as an amphipathic substance RCOO-Na+ Detergent action Digestion of lipid bile acids (salts) Transport of lipids in the blood Functions and mechanisms of the pulmonary surfactants Cell membrane structure Absorption of lipids Entry of steroids into cells a Important amphipathic biomolecules: Chapter 3 Cell Structure and Genetic Control (p 52 55) Biological Membranes
a Membrane lipids spontaneously form bilayers The hydrophobic components face inward, whereas the hydrophilic components face outward a Thin sheetlike structures composed of lipid and protein Membrane lipids create the permeability barrier Membrane proteins serve as pumps, enzymes, receptors, and energy transducers Membranes create compartments ranging from mitochondria and nuclei to entire cells ...
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This note was uploaded on 09/14/2008 for the course VPHY 3100 taught by Professor W during the Fall '05 term at University of Georgia Athens.
- Fall '05