Thermoreguation Flashcards
What is the receptor for core body temperature located. What are the 2 thermosensitive neurons. Which one is more prevalent and what is their response towards a change in core temperature.
POA (preoptic area) at anterior end of hypothalamus.
warmth-sensitive neurons and cold-sensitive neurons
The warmth-sensitive is more prevalent
THe firing rate increase as temperature rises (for warmth). Vice versa
What are the receptors on skin that will be stimulated to detect lambient temperature change
Warmth skin receptor
Cold receptor （more prevalent)
Pain receptor can be stimulated by extreme hot and cold
What are the behavior change to accomodate for the change in temperature
–> Choice of surroundings (under the sun? or
under the shade?)
⎼ Changes in clothing
⎼ Change in voluntary activity
⎼ Curling up
Name the effectors in shivering , and the neuron delivering the signal
And the site of initition of reaction
Skeletal muscle
Motor neuron
Motor centre in the posterior hypothalamus
Name the effector that has a large oil droplet in it
What type of neuron and what is the receptor on the cell
What hormones can stimulate it as well
What happens to the cell upon stimulation by the binding of neurotransmitter
One of the hormone can regulate the Uncoupler. Name it
Brown Adipose tissue
Sympathetic nonadrenergic neurons
β3-adrenergic receptors
thyroid hormones, epinephine
It promotes the breakdown of TAG into fatty acid and glycerol. The mitochondrion express uncoupler protein 1 (UCP1) hence uncouple ATP generation. No ATP is generated but heat upon consumption of nutrients
Thyroid gland can upregulate the upcoupler
Name the effector that secret substance on skin
What type of neuron and what is the neurotransmitter on the cell
What hormones can stimulate it as well
What happens to the cell upon stimulation by the binding of neurotransmitter
Eccrine sweat glands
sympathetic cholinergic neurons
AcetylCholine (Ach)
Epinephrine and norepinephrine
(ie adrenaline and nonadrenaline) by adrenal medulla
It promotes the secretion of sweat
What is the direction of blood flow under skin
Small arteries / arterioles –> capillaries –>
veins –> venous plexus (under the dermis)
For the exposed areas of the body (hands,
feet and ears), venous plexus is connected
to small arteries also through arteriovenous
anastomoses (AV anastomoses).
What controls the rate of blood flow to the skin.
By how
Stimulate by what. What is the receptor
arterioles and AV anastomoses
Vasoconstriction and vasodilation
sympathetic nondadrenaline neuron
α-adrenergic receptors of arterioles and AV anastomoses
Causing vasoconstriction
What population mainly use BAT for heat regulation
Infants
What is the situation in which the set point is elevated
Fever (pyrexia)
What is the situation in which the set point is unchanged but core temperature is above the set point
Hyperthermia
What is the cause, and mechanism in Fever
Bacterial/viral infection/tissue damage cause macrophage to release cytokines
The cytokine travels via the circulatory system to reach the brain to stimulate it to release more PGE2 (Prostaglandin E2)to increase the set point
**Act like core temperature drops
What is the class of drug aspirin and ibuprofen belonging to? What is the mechanism
Antipyretic drug.
It inhibit the production of PGE2
What lead to hyperthermia
Other than high body temperature what are the consequences
If the thermoregulatory system fails, what is the situation called
Strenuous exercise, high ambient temperature and humidity
The profused sweating lead to lost of water and salt
Heat stroke
As one is exposed to hot weather for long, what will happen to the thermoregulatory sysgtem
They have lower salt content in the sweat due to a higher aldosterone by adrenal cortex.
