Comparative Vertebrate Physiology Homeostasis
Course Outline Systems Nervous, Muscular, Circulatory, Respiratory, Osmoregulatory, Digestive, Reproductive Processes Thermoregulation Metabolism
Course content Structure - what does it look like? Function- how does it work? How and Why? The comparative approach
Homeostasis
Claude Bernard’s concept All organs interact All cells of organs bathed in internal fluid Cells exist if fluid remains constant in quantity and quality - quality affects quantity Fluctuations occur within narrow limits
Feedback mechanisms Control system Sensor Set point adjustment Disturbance Error signal Inverted amplifier Negative feedback -
Beneficial - Example: perspiration Doesn’t prevent displacement Restores stability close to operating parameters
Feedback mechanisms Control system Sensor Disturbance Signal Amplifier Positive feedback Output +
Positive feedback Rare and mostly destructive e.g. congestive heart failure Some are beneficial e.g. vomiting
Control systems Integration (CNS) Stimulus Response Effector (muscle, gland) Receptor (cell) AfferentEfferent