Week 1 Tuesday - Downing - Histology of Skin

Question 1

Sebaceous gland

Answer 1

Oily gland of the skin (usually of the hair folicle).

• Holocrine secretion
• Causes acne

Question 2

Meissner’s corpuscle

Answer 2

Nerve ending in the superficial part of the dermis sensitive to light mechanical touch.

Question 3

Pacinian corpuscle

Answer 3

Nerve ending in the deep dermis sensitive to pressure.

It’s big and round, like PAC-man

Question 4

Lamellar bodies

Answer 4

Contain lipids. Secreted from a granular cell superficially. Form a lipid coat (water barrier).

Question 5

Keratohyaline granules

Answer 5

Present once an epithelial cell enters the Stratum granulosum stage. Eventually these consolidate into a fibrous amorphous mass when the cell enters the Stratum Corneum.

Question 6

Psoriasis

Answer 6

Increase in # of proliferating cells in Stratum basale, increase in cell turnover.

Question 7

Papillae

Answer 7

Secondary dermal ridges; exist in epithelial tissues subject to stress e.g. palms.

Question 8

Where do melanin granules come from and how do they mature?

Answer 8

Golgi of melanocyte, are matured via tyrosinase activity, which is active in the first two steps of the following reaction:

tyrosine peptide -> dopa peptide -> [indole 5,6 quinone]n -> Melanin polymer

Question 9

Rete cutaneum (cutaneous plexus)

Answer 9

Supply of veins and arteries in the reticular (deep) layer of the dermis.

Question 10

Rete subpapillare (subpapilary plexus)

Answer 10

Supply of veins and arteries in the papilary (superficial) layer of the dermis. (sometimes just referred to as the papilary plexus).

Question 11

Arteriovenous anastomoses

Answer 11

(AV shunts) Shunts that allow blood flow to bypass the papilary plexus.
Thermoregulated; open when cold, closed when hot.

Question 12

This muscle stands hair ‘on end’ and moves sebaceous gland products. What is it and where is it anchored?

Answer 12

Arrector pili muscle. Bundle of smooth muscle that in innervated sympathetically. Anchored from the hair follicle sheath to the papillary layer of the dermis.

Question 13

Lanugo, vellus, and terminal hair

Answer 13

Lanugo - Newborn hair
Vellus - fine hair that covers most of the body
Terminal hair - rougher hair (pubic hair, facial hair)

Question 14

This tissue is located superficially to finger nail root.

Answer 14

Eponychium.

Question 15

This tissue is located under the tip of the fingernail.

Answer 15

Hyponychium.

Question 16

This is the light crescent on the most proximal part of the finger/toe nail.

Answer 16

Lunula.

Question 17

Eccrine sweat glands

Answer 17

Major sweat glands of the body, active when working out. Sympathetic innervation.

Question 18

Apocrine sweat glands

Answer 18

Sweat glands restricted to the axilla; areolae, and anogenital locations. Activated when nervous. Odorless secretion becomes odored when acted on by bacteria. Sympathetic innervation.

Question 19

Peritrichial nerve endings

Answer 19

They allow feel for when a hair is touched.