Thermoregulation Flashcards Preview

Skin/Musculoskeletal: Anatomy/Dissection > Thermoregulation > Flashcards

Flashcards in Thermoregulation Deck (30)
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1
Q

What branch of the nervous system has major control over both blood flow and sweat gland activation for thermoregulation?

A

sympathetic

2
Q

What circulatory structure in the skin is critical for thermoregulation?

A

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

3
Q

Why are people’s faces when they’re exercising?

A

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.

4
Q

Are sympathetic nerves efferent or afferent?

Where do they originate?

A

they are efferent nerves leaving the spinal cord in the thoracic-lumbar region

5
Q

Where do sympathetic nerves usually synapse?

A

they usually synapse in the paravertebral ganglia on either side of the spinal cord (22 on each side)

6
Q

In sympathetic control of thermoregulation, what neurotransmitter are the preganglionic nerves releasing?

A

acetylcholine

7
Q

What kind of receptors does the acetylcholin work on for the postganglionic nerves?

What is the result?

A

ACh activates postganglionic nicotinic receptors

this depolarizes the postganglionic nerve

8
Q

What neurotransmitter do the activated postganglionic nerves release?

What’s the result?

A

they release norepinephrine

this constructs blood vessels

9
Q

What type of receptor does the norepinephrine work on to contract arterioles?

What kind of receptor is this?

A

the alpha-1 receptor

this is a G-protein coupled receptor

10
Q

Oddly enough, sympathetic nerves can also cause vasodilation in the skin circulation. What neurotransmitter is released by the postganglionic nerve in this case?

A

acethylcholine

11
Q

When your hands are freezing and painful, what’s actually causing the pain?

A

it’s the reperfusion after they start to warm up

12
Q

Why are people more likely to die of hypothermia when they’re drunk?

A

alcohol dilates cutaneous blood vessels and increases heat loss - think about the drunks with flushed faces

13
Q

WHere are sweat glands on the body? In other words, where are they not?

A

They are everywhere except the lips, ear canal, clitoris, labia minora, penis, areolar regions

14
Q

What are the two types of sweat glands and when are each active?

A

eccrine - involved in temperature regulation

apocrine - involved in sweating in stressful situations

15
Q

What is the ultimate controller of sweat gland secretions? Through what nervous system?

A

The temperature sensors in the hypothalamus, affecting through the sympathetic nervous system

16
Q

Release of what neurotramsitter from postganglionic nerves will cause sweating from eccrine glands?

A

acethylcholine

17
Q

In the case of increasing sweating, what receptor is acetylcholine working on?

A

muscarinic receptors

18
Q

What neurotransmitter will activate apocrine sweat glands? Through what receptors?

A

norepinephrine affecting alpha1 and beta receptors

19
Q

What ions are actively secreted by sweat glands?

A

Na, Cl and K

20
Q

What pumps/channels are used in transporting Na, Cl and K into the lumens of sweat glands

A

the NKCC pump (Na, K, 2 Cl) will pump them INTO the secretory cells

the CLCA Chloride antiporter and the CFTR then allow the Cl into the sweat gland lumen

the Na and H20 will follow by the electrochemical gradient and osmosis

21
Q

Once the ions are in the sweat duct, what happens to them?

A

they are reabsorbed by the CFTR (the Cl) and the ENaC (Na channels)

22
Q

Why isn’t the water also reabsorbed in the sweat ducts?

A

there are no aquaporins there

23
Q

What is the net result out of the sweat glands?

A

a dilute solution of ions

Na is only 0.9 g/L

K is slightly concentrated relative to plasma

low HCO3

acid pH

24
Q

If someone has cystic fibrosis, what happens to their sweat?

A

the CFTR is inactive, but the CLCA is still working

this means they’re able to pump the Cl into the sweat gland lumen, but they’re not able to reabsorb it.

this means their sweat is extra salty

25
Q

Atropine blocks sweating by what mechanism?

A

blocks the muscarninic receptors

26
Q

How does furosemide block sweating?

A

it blocks the NKCC pump

27
Q

How does the botulinum toxin block sweating?

A

prevents acetylcholine release from nerves

28
Q

How do beta blockers block sweating?

How is this dangerous to diabetics?

A

It prevents sweating response to hypoglycemia, which is dangerous to people with IDDM because sweating is their key tipoff that their blood sugar is low

29
Q

What neurotransmitter will be released in response to cold?

what neurotransmitter will be released in response to heat?

A

cold = sympathetic nerves release norepinephrine = vasoconstruction via alpha 1 receptors

heat = sympathetic nerves release acetylcholine = dilation via muscarinic receptors

30
Q
A