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Flashcards in Introduction to Skin Deck (63)
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1

What are the three main layers of skin?

Epidermis, dermis and hypodermis (fat layer)

2

What is keratin?

Keratin is an intermediate filament that is most abundant in the stratum corneum (top layer), hair and nails.

3

Where is keratin most abundant in the skin?

Epidermis, stratum corneum (top layer), hair and nails too

4

What are the two types of keratin?

Soft (alpha) and hard (beta) - determined by the secondary structure and suffice bridges

5

What are the four main layers of the epidermis?

Stratum corneum, stratum granulosum, stratum spinosum and stratum basale

6

Describe the stratum corneum layer of the epidermis

Protective layer of the skin with dead cells and intercellular lipids (ceramics) to maintain skin moisture

7

Describe the stratum granulosum layer of the epidermis

This is 2-3 cells thick and has large granules of keratohyalin

8

Describe the stratum spinosum layer of the epidermis

3-4 cells thick with many desmosomes to separate the keratinocytes which gives the layer a spiny appearance

9

Describe the stratum basale layer of the epidermis

Proliferation of epithelial cells occurs here and cells are slightly denser

10

Describe the composition of the basement membrane of the epidermis of the sin

ECM consists of laminin 332, collagen IV and collagen VII

11

What is the role of the basement membrane in the epidermis?

To provide cell polarity, regulate basal function and to anchor the epidermis to the dermis

12

What is the function of the hemidesmosomes in the basement membrane of the epidermis?

Bind the keratin cytoskeleton to the basement membrane

13

What is the role of the dermis?

Provides strength and elasticity to the skin

14

What is the most abundant cell in the dermis?

Fibroblasts

15

What is the function of fibroblasts in the dermis?

Produce elastin, collagen and proteoglycans

16

What is the neuromuscular supply to the dermis like?

Innervated and vascularised

17

What are the three layers of the dermis?

Papillary, reticular and adipose

18

Describe the papillary layer of the dermis

Contains fine, randomly organised type III collagen and elastin, and lies directly below the basement membrane of the epidermis

19

What type of collagen is present in the dermis?

Type III collagen

20

Describe the reticular layer of the dermis

The thickest layer densely packed with collagen providing mechanical strength

21

Which dermal layer is largely responsible for the mechanical strength of the skin, and why?

Reticular layer of the dermis as it is densely packed with collagen

22

What are adherens junctions?

These are more basal than tight joints and involve a cadherin receptor linked to an actin cytoskeleton

23

What are desmosomes?

Provide a connection between intermediate filaments of the cell cytoskeletons of adjacent cells; cadherin receptor is linked to the keratin cytoskeleton

24

What are tight junctions?

These seal adjacent epithelial cells in a narrow band just beneath their apical surface. Claudin and occluding molecules seal the intercellular space

25

What are gap junctions?

These form intercellular pores made up of connexins

26

Name four different types of cell-cell adhesions

Adherens, desmosome, tight junctions and gap junctions

27

Name three types of glands that may be present in the skin

Sebaceous, eccrine sweat gland, apocrine gland

28

What is a sebaceous gland?

Exocrine gland (secreted into duct) usually found attached to a hair follicle which produces sebum to lubricate skin

29

What is acne caused by?

Infection of the sebaceous glands

30

How are sebaceous glands affected by puberty?

The gland is sensitive to androgens, and enlarges at puberty as a result