What is Physiology? - Answers The study of how the body functions
Homeostasis - Answers The ability to maintain relatively stable conditions in the internal
environment
Conditions controlled to maintain homeostasis - Answers - pH
- Temperature
- Blood gases (CO2, O2)
- Blood pressure
- Intercellular and extracellular fluid volumes
Disease - Answers The failure to maintain homeostasis
Nervous system and endocrine system act to: - Answers 1) Maintain homeostasis
2) Permit departures from homeostasis in a controlled manner (pregnancy, growth, or sudden
fright)
Types of nervous system/endocrine responses - Answers 1) Anticipatory Responses
2) Feedback Mechanisms
Anticipatory Responses - Answers - Increase respiratory rate at the start of exercise.
Proprioceptors signal movement before a change in internal conditions.
- May also be learned or behavioural (putting on a coat)
Feedback Mechanisms - Answers - Mechanisms that respond to change in a system.
- Includes negative and postive feebacks
Set point - Answers Range of values of a variable (e.g. body temp.) that do not bring about a
response (i.e. "normal range")
Negative Feedback - Answers - Most common homeostatic control system
- Result of "output" - the variable moves back toward the set point (in opposite negative
direction) to the change that triggered the response ("input")
- e.g. decrease temp --> shiver --> increase temp.
Positive Feedback - Answers - Less common - NOT homeostatic