Skin and Associated Glands Flashcards Preview

Systems Physiology > Skin and Associated Glands > Flashcards

Flashcards in Skin and Associated Glands Deck (53)
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1
Q

What does the skin protect against

A

Physical barrier to bacteria
Excessive dehydration
UV radiation
drug and chemical penetration

2
Q

What are the functions/roles of the skin

A
Protection
Sensation
Thermoregulation
Metabolic functions
Contributes to physical and sexual identity
3
Q

How does the skin contribute to metabolic functions

A

Adipose tissue = major store of energy

Vitamin D synthesised in epidermis

4
Q

What are the 3 major layers of the skin

A

Epidermis
Dermis
Hypodermis

5
Q

What are some features of the dermis layer

A

dense irregular CT: highly vascular and many sensory

receptors

6
Q

What are some features of the hypodermis layer

A

loose CT contains adipose tissue

7
Q

Name some epidermal appendages

A

Hair follicles
Sweat glands
Sebaceous glands
Nails

8
Q

What kind of epithelium is in the epidermis

A

Stratified Squamous Epithelium

9
Q

What is the major cell type in the epidermis

A

Keratinocyte

10
Q

What are the 4 main layers of the epidermis

A
  • Stratum basale (basal layer)
  • Stratum Spinosum (spinous layer)
  • Stratum granulosum (granular layer)
  • Stratum corneum (cornified layer)
11
Q

What is the stratum lucidum

A

Only in extremely thick skin, homogenous between SG and SC

12
Q

Describe a keratinocyte and what does it do

A

most abundant epithelial cell in epidermis, lots of intercellular junctions like desmosomes and adherent junctions
Produce keratin

13
Q

What is the most abundant protein in the stratum corneum

A

Keratin

14
Q

Where besides skin is keratin found

A

Hair and nails

15
Q

What kind of proteins are keratins and what defines soft vs hard keratins

A

Fibrous structural proteins

S-S bonding defines hard vs soft

16
Q

What cells are found in the stratum basal

A
Stem cells
Transit Amplifying (TA) cells
17
Q

What does the stratum basale sit on

A

the basement membrane

18
Q

Can Transit Amplifying cells undergo cell division

A

TA limited cell division before undergoing terminal differentiation

19
Q

What is keratinisation

A

The migration of keratinocytes, which become tightly bound together by desmosomes, from the basal to the corneal layer

20
Q

What gives the stratum spinousum a prickly appearance

A

The numerous desmosomes

21
Q

What is the stratum granulosum characterised by

A

Large, numerous basophilic granules of keratohyalin

keratinocytes from the underlying stratum spinosum migrate here and become known as granular cells here

22
Q

Gives 2 examples of keratohyalin

A
  • Filaggrin

- Involucrin

23
Q

What is synthesised by the stratum granulosum

A

Synthesises glycoprotein granules

24
Q

Describe the cells of the stratum corneum

A
  • Terminally differentiated
  • fused flattened cells without organelles and filled with mature keratin
  • Thick cornified cells envelope under the plasma membrane
  • cells are dead
25
Q

What is the main function of the stratum corneum

A

main protective barrier of the skin

26
Q

What are the 2 layers of the dermis

A
  • Papillary (vascular/nervous
    papillae)
  • Reticular (main fibrous bed,
    dense irregular CT)
27
Q

Describe the general features of the dermis

A
  • Complex mix of
    macromolecules
  • Many blood vessels
28
Q

What are the main functions of the dermis

A
  • Provides strength and elasticity to skin

- Acts as a support for epidermis

29
Q

Name the features the papillary dermis and what type of collagen is in it

A
  • Superficial layer beneath epidermis
  • Contains many blood capillaries (vascular papillae)
  • Loosely packed
  • Type III Collagen
30
Q

What fibres are found in the reticular dermis

A

 Closely packed Type I collagen and elastin

31
Q

What is the main role of the reticular dermis

A
  • Provides much of mechanical strength of skin
32
Q

Is the reticular dermis hydrophobic or hydrophilic

A

Hydrophilic and flexible

33
Q

What is the ground substance in the reticular dermis

A
  • an amorphous matrix that embeds the collagenous and elastic fibres and skin appendages
34
Q

Name 3 GAGs found in the ground substance of the reticular dermis

A
  • Hyaluronic acid
  • Dermatan sulfates
  • Chondroitin sulfates
35
Q

What is the most abundant cell in the dermis

A

Fibroblast

36
Q

What is the function of fibroblasts in the dermis

A

Repair

37
Q

What do fibroblasts synthesise in the dermis

A
  • Collagen
  • Elastin
  • Proteoglycans
38
Q

Name some skin glands

A
  • Eccrine sweat gland
  • Apocrine gland
  • Sebaceous gland
39
Q

What are the 2 types of hair follicle

A

Vellus - body hair

Terminal - scalp and secondary sexual hair

40
Q

What is the dermal papilla

A

root of the hair follicle

41
Q

What in the hair matrix produces hair

A

keratinocytes

42
Q

What does the bulge of the hair follicle contain

A

Hair follicle stem cells

43
Q

What cells is the root of the hair follicle made of

A

3 inner concentric epithelial cells to form the hair shaft

2 outer concentric epithelial forms epithelial sheath

44
Q

What are the 3 main phases of the hair growth cycle

A
  • Anagen-active
  • Catagen-regressive
  • Telogen-resting
45
Q

What kind of gland are sebaceous glands and what do they do

A

Exocrine
Mature sebocytes contain sebum
Cell ruptures and sebum released into sebaceous duct and onto skin to lubricate skin and hair
Gives you acne

46
Q

What is the main role of the eccrine sweat gland

A

thermoregulation

47
Q

What are the 2 main components of the eccrine sweat gland

A

Excretory duct - two layers of smaller cuboidal cells

Compact secretory coil - single layer of large cuboidal/columnar cells

48
Q

What is the largest sweat gland and where are they found

A

Apocrine sweat glands

Axilla (underarm) and pubic region

49
Q

Describe the secretion of apocrine sweat glands and when do they become functional

A
  • Release volatile milky, viscous fluid
  • Secretion is odourless, Body odours, Broken down on skin by bacteria
  • Do not become functional until puberty
50
Q

Where are melanocytes and what do they do

A

In epidermis, on basement membrane

  • Produce melanin in melanosomes
  • Melanosomes injected into keratinocytes
  • Protect against UV
51
Q

Name the 2 types of melanin and what colour they are

A

Eumelanin - Brown-black

Pheomelanin - Red-brown

52
Q

Where in the epidermis are merkel cells and what is there function

A
  • Stratum basale

- Sensory perception

53
Q

Where in the skin are mast cells and what is there function

A

Dermis

  • Immune response
  • Secretes histamine