2/20/24 -Homeostasis
I. Intro. to Homeostasis
- CC Feedback mechanisms
II. Examples of Homeostasis
- CC, HD osmoregulation
mechanisms
III. Homeostasis in Animals
- CC SEQ homeostasis processes
- SEQ, HD glucose homeostasis
I. Intro. to Homeostasis
Remainder of semester - organ systems - focus on humans —> 3 points for each
- Anatomy (bio. form), physiology (bio function), and evolutionary history (how )
A. What is Homeostasis?
Homeo = similar, stasis → standing
- The steady state of physiological conditions in the
body
B. Homeostasis is a basic characteristic of living
things
All living things regulate internal conditions in some way
C. Basic Mechanisms
Generally uses feedback regulation :
Stimulus → response → increase or reduce the stimulus
- which in turn can increase or decrease the response
2 types - Negative and Positive -> negative feedback much more common
Negative feedback - response to stimulus reduces stimulus
A to B B reduces intensity of A → change, gets undone, stimulus and
response goes away
(1) Ex: regulate body temp, too cold → body heats up etc.; balance (2)
Most biological processes (3) Returns level to a set point (4) Response reduces the stimulus
Positive feedback - response to stimulus amplifies stimulus → relatively uncommon
A to B B strengthens intensity of A, → increases the response in turn
(1) Ex: childbirth → contractions signal uterus to release hormones (2) Stimulus brings a change in
state(3) Suckling → milk production (4) Keeps building for response
