1. Biology 346 General Physiology Dr. Tony Serino
Introduction
Biology 346 General Physiology
Dr. Tony Serino

2. Physiology
Physiology –study of body mechanisms (homeostasis)

3. Homeostasis Maintenance of a constant internal environment
Uses a reflex arc to self regulate
Reflex functions to maintain a certain set point with a narrow physiological range

4. Homeostasis Reflex

6. Homeostatic Pathways

7. Factors Affecting Homeostasis
Feedback –negative or positive
Feed-forward regulation
Acclimatization
Biorhythms

9. Internal vs. External Environment

10. Atmosphere External Environment Composition: 78% N2, 20% O2, 0.3% CO2
Pressure at Sea Level = 101kPa (760mm Hg)
Pressure decline by half for every 5500m increase in altitude
Partial Pressure (PP) of a gas = its fractional percent * total press.
Temperature range: -70oC to 50oC; declines 6-10oC per 1000m altitude from sea level

11. Aquatic Environments Composition: salts, ions, dissolved gases
Temp.: ~0-100oC
Pressure increases 1 atm per 10 m depth
Mean depth of ocean is 3800m
Most light absorbed by 8m depth

12. Terrestrial Environments
Biomes: classed by water abundance, temp. and dominant community
Subterranean environments might have lower oxygen and higher carbon dioxide levels and of course little to no light sources

13. Internal Environment
Composition by weight: 60-90% water, 18% protein, 15% fat, 7% mineral
63% H, 25% O, 9.5% C, 1.4% N
Minor elements (<1%)
Trace elements (<0.01%)

14. Body Fluids
Transcellular fluids are filtrates of the plasma

15. Important Ions