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)
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1
Q

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

A

Dermo-epidermal junction

2
Q

2 groups of purposes of the DEJ?

A

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

3
Q

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

A

It is the basement membrane

4
Q

3 parts of the DEJ?

A

Lamina lucida
Lamina densa
Sub-lamina densa zone

5
Q

What are the components of the dermis? (6)

A
Fibres (collagen, elastin)
Cells (fibroblasts, macrophages, mast cells, lymphocytes, Langerhans cells)
Ground substance
Blood vessels
Lymphatics
Nerves
6
Q

What does collagen do to the skin?

A

Makes it very strong

7
Q

What type of collagen is in the dermis?

A

Matrix of type I and type III collagen

8
Q

What does elastin do to the skin?

A

Makes it spring back into shape

9
Q

What do fibroblasts do?

A

Secrete collagen

10
Q

What is the purpose of macrophages in the dermis?

A

Scavengers, antigen presentation

11
Q

What is the purpose of mast cells in the dermis?

A

Chemical messengers

12
Q

What is ground substance?

A

A gel like substance that surrounds cells absorbing water

13
Q

What are 2 examples of ground substances?

A

Mucopolysaccharides

Glycosaminoglycans

14
Q

What are the 2 parts of the dermis?

A
Papillary dermis (thin)
Reticular dermis (thicker) - contain appendages
15
Q

How does exposure to UV light age the skin?

A

By destroying the collagen and elastin fibres

16
Q

What is solar elastosis?

What is this process known as?

A

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
Q

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

A

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

18
Q

Flow of blood from arterioles to collecting venules?

A

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

19
Q

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

A

smaller non-contractile vessels -> larger contractile lymphatic trunks

20
Q

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

A

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

21
Q

What areas of the body have many meissners corpuscles?

Why?

A

Finger tips and around mouth

Very sensitive to fine touch

22
Q

What do the autonomic nerves of the dermis supply?

A

Blood vessels

Glands

23
Q

What are the 3 types of skin glands?

A

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

24
Q

Are sebaceous glands hormone sensitive?

A

Yes - they are dormant pre-puberty

25
Q

What do sebaceous glands produce?

A

Sebum

26
Q

What is sebum made up of? (4)

A

Squalene
Wax esters
Triglycerides
Free fatty acids

27
Q

Where do sebaceous glands mainly open onto?

A

Hair follicles

28
Q

Function of sebum? (2)

A

Control moisture loss

Protection from bacterial and fungal infection

29
Q

Where are apocrine sweat glands mainly found?

A

Sexual areas e.g. axillae, nipple and perineum

30
Q

Are apocrine sweat glands hormone dependant?

A

Yes - tend to start working at puberty

31
Q

what do apocrine sweat glands produce?

A

An oily fluid that smells after bacterial decomposition - “scent gland”

32
Q

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

A

apocrine

33
Q

Where are eccrine sweat glands found?

A

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

34
Q

What nerve supply do eccrine glands receive?

Stimulation?

A

Sympathetic cholinergic nerve supply

Mental, thermal and gustatory (taste) stimulation

35
Q

How many eccrine sweat glands does the body have?

A

2 - 4 million

36
Q

3 functions of sweat? - eccrine sweat glands

A

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