Skin Flashcards Preview

Histology > Skin > Flashcards

Flashcards in Skin Deck (41):
1

Functions of skin

Protection against chemical, thermal and mechanical insults, bacterial and fungal invasion, dessication and uv light
Has sensors for touch, pressure, pain and temperature
Thermoregulation
Production of vitamin D3
Significant energy store

2

Layers of skin

Epidermis, dermis and hypodermis

3

Epidermis

Composed of keratinised stratified squamous epithelium

4

Dermis

Composed of a layer of fibrocollageous and elastic connective tissue that contains blood vessels, nerves and sensory receptors

5

Hypodermis

Composed mainly of adipose tissue
Varies in thickness
Scattered septa made up of bundles of collagen

6

What is the function of septa in the hypodermis

Help anchor the skin to the underlying deep fascia

7

Layers of the epidermis

Stratum basale, stratum spinosum, stratum granulosum and stratum corneum

8

What is a possible 5th layer of the epidermis

Stratum lucidum

9

Statum basale

Single layer of cells sitting on basal lamina
Stem cells for the epidermis

10

Stratum spinosum

5 cells thick
Many desmosomes attaching cells to each other

11

Stratum granulosum

Cells aquire large numbers of dense cytoplasmic granules
Cells produce lamellar bodies
Further up the layer, the cells gain more keratin and organelles are being progressively lost

12

Stratum corneum

Composed of dead squamous cells packed with keratin in a specialised matrix

13

What are the dense cytoplasmic granules called

Keratohyalin granules

14

What do keratohyalin granules contain

Profilaggrin

15

What does profilaggrin promote

The aggregation of cytokeratin intermediate filaments

16

Aggregations of cytokeratin intermediate filiments known as

Keratin

17

Stratum lucidum

Thin layer found only in thick skin consisting of dead cells with abundant keratin

18

Non-keratinising cells of epidermis

Melanocytes, langerhans' cells and merkel cells

19

Melanocytes

Many long cell processes
Produce melanin

20

What does melanin complex with and what does it form

Proteins to form melanoprotiens

21

What are melanoprotiens passed to and through

Keratinocytes and through granules called melanosomes

22

Two forms of melanin

Pheomelanin and eumelanin

23

Langerhans' cells

Resident immune cells
Act as antigen presenting cells
Have a network of cell processes to increase surface area
Numbers increase during inflammatory conditions
Invade the skin from the blood stream

24

Merkel cells

Touch receptors found in basal layer of epidermis
Associated with a nerve ending and form low threshold/slowly adapting receptors

25

Two layers of dermis

Papillary dermis - superficial
Reticular dermis - deep

26

Papillary dermis

Forms dermal papillae which project upwards and interdigitate with downwards projections of the epidermis called rete ridges
Consists of bundles of fine collagen and elastic tissue

27

Reticular dermis

Forms dense irregular connective tissue with thick bundles of collagen fibres and elastic fibres embedded in small amounts of extracellular material

28

Other name for hypodermis

Subcutis

29

Epidermal skin appendages

Hair follicles, sebacous glands and sweat glands

30

Hair follicles

Tubular structure extending down through the epi into the dermis and hypo
Has 5 layers
At the bottom extension = hair bulb
Concave region = dermal hair papilla

31

Sebaceous gland

Usually associated with hair follicle
Produce sebum
Utilise holocrine secretion

32

Arrector pili muscles

Associated with hair follicle
Small band of muscle
Runs obliquely upwards and ends in upper part of dermis
Innervated by sympathetic nervous system

33

Sweat glands

2 types - eccrine and apocrine
Coiled tube located near junction of dermis and hypo
Made up of secretory and duct segements

34

Secretory segment of sweat gland

Coiled tubular gland
Pseudostratified epithelium

35

Duct segment of sweat gland

Initially coiled but then straightens
Stratified cuboidal epithelium

36

Apocrine sweat glands

Restricted to axillae, genitalia and areolae of the nipple
Produce a milky fluid
Ducts typically end on hair follicles
Secretory sections have large lumen
Utilise merocrine secretion

37

Nails

Hard plates of keratin
Formed by cells of the nail matrix
Nail bed is analogus and continuous with epidermis

38

Visible half moon portion of nail matrix

Lunula

39

Sensory receptors of skin can be classified by

Free nerve endings or encapsulated nerve endings

40

Free nerve endings form

Meissner's corpusce

41

Encapsulated nerve endings from

Pacinian corpuscle