Homeostasis Flashcards
1
Q
Define Homeostasis
A
maintaining relatively constant conditions despite constant changes in the external environment
2
Q
Define auto regulation
A
- the automatic response in a cell, tissue or organ to some environmental change
3
Q
Define Extrinsic regulation
A
Responses controlled by nervous & endocrine systems
4
Q
What are the 3 components of homeostasis ?
A
- receptors
- control centres
- effectors
5
Q
What are some biological variables involved in homeostasis ?
A
- body temp
- body fluid composition & volume
- blood pressure
6
Q
Define the Set Point
A
- designated value/range of a biological variable
7
Q
What is the set point for body temp?
A
37 degrees
8
Q
What is the set point for blood glucose levels ?
A
4.0 - 5.9 mmol/L
9
Q
What is the set point for potassium levels?
A
3.6 - 5.2 mmol/L
10
Q
Describe receptors
A
- body structure that monitors changes in a controlled condition
- sends input to a control centre
11
Q
Describe Control Centres
A
- example = Brain
- sets the set points for a controlled condition
- evaluates received input & generates output commands when necessary
12
Q
What do output commands typically occur as ?
A
- hormones or nerve impulses
13
Q
Describe Effectors
A
- body structure that receives output from control centre
- produces a response/effect that changes the controlled condition
14
Q
Define Positive Feedback
A
- body is moved away from homeostasis
- used to speed processes
- response of the effector increases change of the stimulus
15
Q
Define Negative Feedback
A
- response of effector negates the stimuli
- body is brought back into homeostasis
