Skin 3 - Physiology

Question 1

What are the 5 skin receptors?

Answer 1

Free nerve endings, tactile discs, tactile corpuscles, lamellar corpuscles, bulbous corpuscles

Question 2

These receptors are mostly unmyelinated small diameter fibres, but some small diameter myelinated fibres that have small swellings at distal ends. It is the most common receptor in skin

Answer 2

Free nerve endings

Question 3

These are small swellings at distal ends that have receptors that correspond to various stimuli (nociceptive, thermal, chemical)

Answer 3

Sensory terminals

Question 4

TRPV1 receptors are an example of?

Answer 4

Cation channels that may be found in the sensory terminals

Question 5

H1 receptors are an example of?

Answer 5

Chemical receptors that may be found in the sensory terminals

Question 6

These are free nerve endings located in the deepest/basal layer of the epidermis. (it doesn’t extend all the way down to the dermis)

Answer 6

Tactile/Merkel discs

Question 7

What is the hormone responsible for communication between tactile epithelial cell and nerve ending?

Answer 7

Serotonin

Question 8

What kind of receptors are usually found abundant in finger tips (with small receptive fields?)

Answer 8

Tactile discs

Question 9

This is a receptor sensitive to an objects physical features like fine touch and light pressure as well as texture, shape and edges

Answer 9

Tactile discs

Question 10

This is located in papillary layer of the dermis and are spiraling, branching unmyelinated sensory terminals surrounded by modified Schwann cells and a thin oval connective tissue capsule.

Answer 10

Tactile corpuscles

Question 11

This is a receptor commonly found in finger pads, lips, eyelids, external genitalia, soles of feet or nipples.

Answer 11

Tactile corpuscles

Question 12

These receptors are sensitive to shape and textural changes in exploratory touch like reading Braille text; as well as low frequency vibrations.

Answer 12

Tactile corpuscles

Question 13

These are scattered deep in the dermis and hypodermis. It is a single dendrite lying within concentric layers of collagen fibres and specialised fibroblasts.

Answer 13

Lamellar corpuscles

Question 14

How are the layers of lamellar corpuscle separated from each other?

Answer 14

Through gelatinous interstitial fluid

Question 15

How does lamellar corpuscle trigger an AP?

Answer 15

If deep and sustained pressure is applied, the capsule that surrounds the corpuscle is deformed and forms a pressure wave that goes to the middle to open pressure sensitive Na+ channels in sensory axon.

Question 16

This receptor relaxes quickly and so APs are rapidly adapting.

Answer 16

Lamellar corpuscle

Question 17

This receptor is stimulated by deep pressure and vibration.

Answer 17

Lamellar corpuscle

Question 18

This is located in the dermis and subcutaneous tissue. It is a network of nerve endings intertwined with a core of collagen fibres that are continuous with those of surrounding dermis. A capsule surrounds the entire structure.

Answer 18

Bulbous corpuscle

Question 19

This receptor is sensitive to sustained deep pressure and stretching or distortion of the skin.

It plays a role for signaling continuous states of ddeformation of the tissues.

Answer 19

Bulbous corpuscle

Question 20

What kind of receptors are usually found in joint capsule?

Answer 20

Bulbous corpuscle

Question 21

What does the bulbous corpuscle help with in the joint capsule?

Answer 21

Proprioception/degree of joint rotation

Question 22

What does the bulbous corpuscle help with in fingers?

Answer 22

To modulate grip (monitor slippage of objects)

Question 23

This is the reduced activation of a1 receptors on vascular smooth muscle and so increases blood flow to the skin

Answer 23

Vasodilation

Question 24

This is the activation of a1 receptors on vascular smooth muscle to decrease blood flow to the skin

Answer 24

Vasoconstriction

Question 25

During vasoconstriction there is?
a) increased extracellular calcium and GPCR couples to intracellular 2nd messengers
b) decrease extracellular calcium and GPCR couples to intracellular 2nd messengers
c) increased intracellular calcium and GPCR couples to intracellular 2nd messengers
d) increased intracellular calcium and GPCR couples to intracellular 2nd messengers

Answer 25

C) increased calcium and GPCR couples to intracellular 2nd messengers

• increased calcium means more actin-myosin interactions

Question 26

This happens during heat stress and exercise. Where the body responds to an increase in core temperature with large amounts of blood flow to the skin.

Answer 26

Active vasodilation

Question 27

What are the primary mechanisms of heat transfer?

Answer 27

Convection, conduction, evaporation, radiation

Question 28

These are glands innervated by sympathetic cholinergic nerves. It may also be stimulated by adrenalin in response to stressful stimuli.

Answer 28

Eccrine sweat glands

Question 29

What does it sympathetic cholinergic mean?

Answer 29

These specific sympathetic nerves release Ach instead of norepinephrine

Question 30

This is the area of the hypothalamus that contains heat and cold sensitive neurons.

Answer 30

Preoptic area

Question 31

What are 3 potential complications of severe burns?

Answer 31

Dehydration + hypovolemic shock
Infection/sepsis
Hypothermia

Question 32

These are muscles innervated by a1 receptors and attach the hair follicle to the upper dermis. The contractions pulls hairs upright in response to cold stimuli.

Answer 32

Arrector pili muscles

Question 33

What receptors are found on arrector pili muscles?

Answer 33

a1 receptors

Question 34

What are the heat generating mechanisms?

Answer 34

Thermogenesis (heat generation)
- shivering - ATP turning into ADP + Pi + movement + heat
- non-shivering - increased SNS activation - increases adrenalin production in adrenal medulla - increases amount of intracellular Ca2+ - which leads to vasoconstriction of blood vessels.
- increased cellular metabolism (glycogenolysis AKA formation of energy/glucose/ATP in the liver and the muscle)
- uncoupling of Oxidative Phosphorylation to produce heat rather than ATP
- Increased Thryoxine production to increase BMR
- arrector pili muscle - traps heat in to conserve heat