Skin Structure and Function 3 Flashcards Preview

2nd Year - Dermatology > Skin Structure and Function 3 > Flashcards

Flashcards in Skin Structure and Function 3 Deck (36):
1

What is the name of the interface between the epidermis and dermis?

Dermo-epidermal junction

2

2 groups of purposes of the DEJ?

Support, anchorage, adhesion, growth and differentiation of epidermal cells
Semi-permebale membrane acting as a barrier and filter

3

How is the DEJ related to the above epithelium (the epidermis)?

It is the basement membrane

4

3 parts of the DEJ?

Lamina lucida
Lamina densa
Sub-lamina densa zone

5

What are the components of the dermis? (6)

Fibres (collagen, elastin)
Cells (fibroblasts, macrophages, mast cells, lymphocytes, Langerhans cells)
Ground substance
Blood vessels
Lymphatics
Nerves

6

What does collagen do to the skin?

Makes it very strong

7

What type of collagen is in the dermis?

Matrix of type I and type III collagen

8

What does elastin do to the skin?

Makes it spring back into shape

9

What do fibroblasts do?

Secrete collagen

10

What is the purpose of macrophages in the dermis?

Scavengers, antigen presentation

11

What is the purpose of mast cells in the dermis?

Chemical messengers

12

What is ground substance?

A gel like substance that surrounds cells absorbing water

13

What are 2 examples of ground substances?

Mucopolysaccharides
Glycosaminoglycans

14

What are the 2 parts of the dermis?

Papillary dermis (thin)
Reticular dermis (thicker) - contain appendages

15

How does exposure to UV light age the skin?

By destroying the collagen and elastin fibres

16

What is solar elastosis?
What is this process known as?

Accumulation of abnormal elastin in the dermis of the skin, or in the conjunctiva of the eye, which occurs as a result of the cumulative effects of prolonged and excessive sun exposure = photoageing

17

What are the names of the 2 plexus of blood vessels that form in the dermis?

Superficial vascular plexus
Deep vascular plexus
(these are horizontal plexus)

18

Flow of blood from arterioles to collecting venules?

arterioles -> precapillarly spincters -> arterial capillaries -> venous capillaries -> post-capillary venules -> collecting venules

19

What type of lymphatic vessels does lymph in the skin flow from and to?

smaller non-contractile vessels -> larger contractile lymphatic trunks

20

Somatic sensory nerve supply of the dermis? + what they sense?

Free nerve endings (for pain)
Special receptors:
Pacinian (pressure/ temperature) corpuscles
Meissners (vibration) corpuscles

21

What areas of the body have many meissners corpuscles?
Why?

Finger tips and around mouth
Very sensitive to fine touch

22

What do the autonomic nerves of the dermis supply?

Blood vessels
Glands

23

What are the 3 types of skin glands?

Eccrine glands
Apocrine glands
Sebaceous glands (part of the pilosebaceous unit)

24

Are sebaceous glands hormone sensitive?

Yes - they are dormant pre-puberty

25

What do sebaceous glands produce?

Sebum

26

What is sebum made up of? (4)

Squalene
Wax esters
Triglycerides
Free fatty acids

27

Where do sebaceous glands mainly open onto?

Hair follicles

28

Function of sebum? (2)

Control moisture loss
Protection from bacterial and fungal infection

29

Where are apocrine sweat glands mainly found?

Sexual areas e.g. axillae, nipple and perineum

30

Are apocrine sweat glands hormone dependant?

Yes - tend to start working at puberty

31

what do apocrine sweat glands produce?

An oily fluid that smells after bacterial decomposition - "scent gland"

32

Do apocrine or eccrine sweat glands open onto the hair follicle?

apocrine

33

Where are eccrine sweat glands found?

Everywhere although the palm, soles and axillae in particular (not found in lips and genitals)

34

What nerve supply do eccrine glands receive?
Stimulation?

Sympathetic cholinergic nerve supply
Mental, thermal and gustatory (taste) stimulation

35

How many eccrine sweat glands does the body have?

2 - 4 million

36

3 functions of sweat? - eccrine sweat glands

Cooling by evaporation (combination of slat and water causes sweat to evaporate)
Moistens palms/ soles to aid grip
Salt loss