Homeostasis Flashcards
1
Q
What is homeostasis?
A
The maintenance if a constant internal environment
2
Q
Examples of homeostasis?
A
- Body water content
- Body temperature
- Bloody sugar level
3
Q
What are the main ways the body controls its temperature?
A
- Sweating
- Shivering
- Controlling heat loss by controlling the amount of blood which flows near the surface of the skin
4
Q
How does hairs standing on end effect heat loss?
A
- Traps a layer of air which provides insulation (like a seals blubber)
- Less heat loss
5
Q
How does less sweat effect heat loss?
A
- Less heat loss via evaporation
6
Q
How does vasoconstriction effect heat loss?
A
- Arterioles supplying the capillaries near the surface of the skin get narrower (constrict)
- Less blood will flow through capillaries near skin surface
Therefore less heat loss by radiation
7
Q
How does hairs lying flat effect heat loss?
A
- No insulating layer of air
- More heat loss
8
Q
How does more sweat being released effect heat loss?
A
- Sweat evaporates more, taking heat energy away
- More heat lost
9
Q
How does vasodilation effect heat loss?
A
- Arterioles supplying the capillaries near the surface of the skin get wider (dilate)
- More blood flows through capillaries near surface of skin
Therefore more heat is loss by radiation
10
Q
How are the body’s water levels changed?
A
Changing the permeability of the collecting duct in the nephron
11
Q
What hormone controls the body’s water levels?
A
ADH (Anti Diuretic Hormone)
12
Q
How does ADH change the body’s water levels?
A
- ADH is carried in the blood
- Collecting duct is surrounded by capillaries
- ADH diffuses out of blood and binds with the receptors on the surface of the collecting duct cells
- This triggers the collecting duct walls to become more permeable to water
Therefore more water is reabsorbed into the blood, less urine produced, becoming more concentrated (darker colour)
