Skin and Associated Glands

Question 1

What does the skin protect against

Answer 1

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

Question 2

What are the functions/roles of the skin

Answer 2

Protection
Sensation
Thermoregulation
Metabolic functions
Contributes to physical and sexual identity

Question 3

How does the skin contribute to metabolic functions

Answer 3

Adipose tissue = major store of energy

Vitamin D synthesised in epidermis

Question 4

What are the 3 major layers of the skin

Answer 4

Epidermis
Dermis
Hypodermis

Question 5

What are some features of the dermis layer

Answer 5

dense irregular CT: highly vascular and many sensory

receptors

Question 6

What are some features of the hypodermis layer

Answer 6

loose CT contains adipose tissue

Question 7

Name some epidermal appendages

Answer 7

Hair follicles
Sweat glands
Sebaceous glands
Nails

Question 8

What kind of epithelium is in the epidermis

Answer 8

Stratified Squamous Epithelium

Question 9

What is the major cell type in the epidermis

Answer 9

Keratinocyte

Question 10

What are the 4 main layers of the epidermis

Answer 10

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

Question 11

What is the stratum lucidum

Answer 11

Only in extremely thick skin, homogenous between SG and SC

Question 12

Describe a keratinocyte and what does it do

Answer 12

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

Question 13

What is the most abundant protein in the stratum corneum

Answer 13

Keratin

Question 14

Where besides skin is keratin found

Answer 14

Hair and nails

Question 15

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

Answer 15

Fibrous structural proteins

S-S bonding defines hard vs soft

Question 16

What cells are found in the stratum basal

Answer 16

Stem cells
Transit Amplifying (TA) cells

Question 17

What does the stratum basale sit on

Answer 17

the basement membrane

Question 18

Can Transit Amplifying cells undergo cell division

Answer 18

TA limited cell division before undergoing terminal differentiation

Question 19

What is keratinisation

Answer 19

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

Question 20

What gives the stratum spinousum a prickly appearance

Answer 20

The numerous desmosomes

Question 21

What is the stratum granulosum characterised by

Answer 21

Large, numerous basophilic granules of keratohyalin

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

Question 22

Gives 2 examples of keratohyalin

Answer 22

• Filaggrin

- Involucrin

Question 23

What is synthesised by the stratum granulosum

Answer 23

Synthesises glycoprotein granules

Question 24

Describe the cells of the stratum corneum

Answer 24

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

Question 25

What is the main function of the stratum corneum

Answer 25

main protective barrier of the skin

Question 26

What are the 2 layers of the dermis

Answer 26

- Papillary (vascular/nervous papillae) - Reticular (main fibrous bed, dense irregular CT)

Question 27

Describe the general features of the dermis

Answer 27

- Complex mix of macromolecules - Many blood vessels

Question 28

What are the main functions of the dermis

Answer 28

- Provides strength and elasticity to skin | - Acts as a support for epidermis

Question 29

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

Answer 29

- Superficial layer beneath epidermis - Contains many blood capillaries (vascular papillae) - Loosely packed - Type III Collagen

Question 30

What fibres are found in the reticular dermis

Answer 30

 Closely packed Type I collagen and elastin

Question 31

What is the main role of the reticular dermis

Answer 31

- Provides much of mechanical strength of skin

Question 32

Is the reticular dermis hydrophobic or hydrophilic

Answer 32

Hydrophilic and flexible

Question 33

What is the ground substance in the reticular dermis

Answer 33

- an amorphous matrix that embeds the collagenous and elastic fibres and skin appendages

Question 34

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

Answer 34

- Hyaluronic acid - Dermatan sulfates - Chondroitin sulfates

Question 35

What is the most abundant cell in the dermis

Answer 35

Fibroblast

Question 36

What is the function of fibroblasts in the dermis

Answer 36

Repair

Question 37

What do fibroblasts synthesise in the dermis

Answer 37

- Collagen - Elastin - Proteoglycans

Question 38

Name some skin glands

Answer 38

- Eccrine sweat gland - Apocrine gland - Sebaceous gland

Question 39

What are the 2 types of hair follicle

Answer 39

Vellus - body hair | Terminal - scalp and secondary sexual hair

Question 40

What is the dermal papilla

Answer 40

root of the hair follicle

Question 41

What in the hair matrix produces hair

Answer 41

keratinocytes

Question 42

What does the bulge of the hair follicle contain

Answer 42

Hair follicle stem cells

Question 43

What cells is the root of the hair follicle made of

Answer 43

3 inner concentric epithelial cells to form the hair shaft | 2 outer concentric epithelial forms epithelial sheath

Question 44

What are the 3 main phases of the hair growth cycle

Answer 44

- Anagen-active - Catagen-regressive - Telogen-resting

Question 45

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

Answer 45

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

Question 46

What is the main role of the eccrine sweat gland

Answer 46

thermoregulation

Question 47

What are the 2 main components of the eccrine sweat gland

Answer 47

Excretory duct - two layers of smaller cuboidal cells | Compact secretory coil - single layer of large cuboidal/columnar cells

Question 48

What is the largest sweat gland and where are they found

Answer 48

Apocrine sweat glands | Axilla (underarm) and pubic region

Question 49

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

Answer 49

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

Question 50

Where are melanocytes and what do they do

Answer 50

In epidermis, on basement membrane - Produce melanin in melanosomes - Melanosomes injected into keratinocytes - Protect against UV

Question 51

Name the 2 types of melanin and what colour they are

Answer 51

Eumelanin - Brown-black | Pheomelanin - Red-brown

Question 52

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

Answer 52

- Stratum basale | - Sensory perception

Question 53

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

Answer 53

Dermis - Immune response - Secretes histamine