KA4- Hypothalamus Flashcards
Where is the hypothalamus?
In the brain
What is the hypothalamus?
The body’s temperature monitoring centre
What does the hypothalamus act as?
A thermostat
How does the hypothalamus receive nerve impulses?
Through thermoreceptors in the skin
What does the hypothalamus also contain?
Internal thermoreceptors
What do these internal thermoreceptors detect?
Change in the blood temperature
How does the thermoregulatory centre respond to changes?
By sending nerve impulses out to various effectors
Where is the thermoregulatory centre?
In the hypothalamus
What does the skin act as?
An effector
What does the skin respond to?
Nerve impulses from the hypothalamus
What is vasoconstriction?
Arterioles leading to the skin become constructed, reducing blood flow to the surface and less heat is lost by radiation
What is vasodilation?
Skin arterioles dilate, which allows a large volume of blood into the skin capillaries and causes more heat to be lost by radiation
What loses more heat; vasodilation or vasoconstriction?
Vasoconstriction
What does every hair have?
Its own erector muscle
What happens to the erector muscle in cold conditions?
Muscle contracts, raising hairs from the skin’s surface and trapping a layer of air around the body
Why does the erector muscle act as an insulator?
As the muscle contracts, the raised hairs from the skin’ surface trap a layer of air around the body
When is sweat released?
In very hot conditions
Where is sweat released?
Onto the surface of the skin
What releases sweat?
Sweat glands
When do sweat glands not produce heat?
In cold conditions
How does shivering generate heat?
By rapid skeletal muscle contractions causing friction between the muscle fibres
When do we shiver?
In very cold conditions
When does MR increase?
In cold conditions
When does MR decrease?
In hot conditions
Why does MR increase in cold conditions?
As it generates more heat
Why does MR decrease in hot conditions?
As it generates less heat
