Thermoregulation Flashcards
What branch of the nervous system has major control over both blood flow and sweat gland activation for thermoregulation?
sympathetic
What circulatory structure in the skin is critical for thermoregulation?
arterio-venous anastomoses
it means the cutaneous arterioles can bypass the capillaries by shunting blood directly into venules. This means the blood won’t pass near the surface of the skin, and heat loss will be reduced
Why are people’s faces when they’re exercising?
the AV shunts are open so more blood is passing thorugh the capillaries close to the skin surface in an attempt to cool the body.
Are sympathetic nerves efferent or afferent?
Where do they originate?
they are efferent nerves leaving the spinal cord in the thoracic-lumbar region
Where do sympathetic nerves usually synapse?
they usually synapse in the paravertebral ganglia on either side of the spinal cord (22 on each side)
In sympathetic control of thermoregulation, what neurotransmitter are the preganglionic nerves releasing?
acetylcholine
What kind of receptors does the acetylcholin work on for the postganglionic nerves?
What is the result?
ACh activates postganglionic nicotinic receptors
this depolarizes the postganglionic nerve
What neurotransmitter do the activated postganglionic nerves release?
What’s the result?
they release norepinephrine
this constructs blood vessels
What type of receptor does the norepinephrine work on to contract arterioles?
What kind of receptor is this?
the alpha-1 receptor
this is a G-protein coupled receptor
Oddly enough, sympathetic nerves can also cause vasodilation in the skin circulation. What neurotransmitter is released by the postganglionic nerve in this case?
acethylcholine
When your hands are freezing and painful, what’s actually causing the pain?
it’s the reperfusion after they start to warm up
Why are people more likely to die of hypothermia when they’re drunk?
alcohol dilates cutaneous blood vessels and increases heat loss - think about the drunks with flushed faces
WHere are sweat glands on the body? In other words, where are they not?
They are everywhere except the lips, ear canal, clitoris, labia minora, penis, areolar regions
What are the two types of sweat glands and when are each active?
eccrine - involved in temperature regulation
apocrine - involved in sweating in stressful situations
What is the ultimate controller of sweat gland secretions? Through what nervous system?
The temperature sensors in the hypothalamus, affecting through the sympathetic nervous system
