Histology of Skin

Question 1

Functions of the skin

Answer 1

• Physical protection
• Thermoregulation
• Sensation
• Metabolic functions
• Indicator of general health

Question 2

3 layers of skin

Answer 2

• Epidermis
• Dermis
• Hypodermis

Question 3

What type of epithelium is the epidermis?

Answer 3

Keratinised stratified squamous

Question 4

What are the layers of the epidermis? (superficial to deep)

Answer 4

• Stratum corneum
• (Stratum lucidum)
• Stratum granulosum
• Stratum spinosum
• Stratum basale

Question 5

What is the stratum corneum made of?

Answer 5

Squames with no cytoplasm or organelles, instead filled with keratin

Question 6

What do the granules in the stratum granulosum contain?

Answer 6

Keratohyalin

Question 7

What connects the cells in the stratum spinosum?

Answer 7

Desmosomes

Question 8

What is produced in the stratum spinosum?

Answer 8

Cytokeratin

Question 9

Where does mitosis in the epidermis occur?

Answer 9

Stratum basale

Question 10

What types of other cells are in the epidermis?

Answer 10

• Melanocytes
• Merkel cells
• Langerhan’s

Question 11

At what layer are melanocytes found and what do they do?

Answer 11

• Stratum basale
• Offer UV protection and melanin

Question 12

At what layer are Merkel cells found and what do they do?

Answer 12

• Stratum basale
• Associated with free nerve endings - light touch receptor

Question 13

At what layer are Langerhan’s found and what do they do?

Answer 13

• All layers and dermis
• Immune cell

Question 14

Layers of the dermis

Answer 14

• Papillary layer
• Reticular layer

Question 15

What tissue is the papillary layer made of?

Answer 15

Loose connective tissue

Question 16

What structures does the papillary layer contain, and what is their function?

Answer 16

Dermal papillae, which provide surface area

Question 17

What tissue is the reticular layer made of?

Answer 17

Dense irregular collagenous connective tissue

Question 18

What else is present in the tissue of the dermis?

Answer 18

Elastin

Question 19

What blood vessel structures provide blood supply to the epidermis and where are they located?

Answer 19

• Papillary loops
• Found in the dermal papillae

Question 20

What 2 plexuses of blood vessels are present in the dermis?

Answer 20

• Subpapillary plexus
• Cutaneous plexus

Question 21

Where are the 2 plexuses found?

Answer 21

• Subpapillary is superficial in the dermis
• Cutaneous is deep in the dermis

Question 22

What connects the 2 plexuses?

Answer 22

Shunting vessels

Question 23

What is the importance of shunting vessels in thermoregulation?

Answer 23

• Controlled by ANS
• Can vasoconstrict to prevent blood supply to periphery

Question 24

Types of mechanoreceptors in the skin

Answer 24

• Free nerve endings
• Merkel disks
• Meissner’s corpuscles
• Ruffini endings
• Pacinian corpuscles

Question 25

Where are each of the mechanoreceptors found?

Answer 25

- FNE = epidermis - MD = papillary layer of dermis - MC = dermis - RE = dermis - PC = subcutaneous layer

Question 26

What do each of the mechanoreceptors detect?

Answer 26

- FNE = pain - MD = perception of shape, texture - MC = motion detection, grip control - RE = skin stretch, tangential force - PC = perception of distant events through vibrations

Question 27

Where do hairs develop from?

Answer 27

Hair follicles

Question 28

What do sebaceous glands secrete?

Answer 28

Oily sebum

Question 29

Where do sebaceous glands secrete?

Answer 29

- Commonly hair follicles - Sometimes independent

Question 30

What type of secretion do sebaceous glands use?

Answer 30

Holocrine secretion - cell fills with secretory vesicles then dissociates

Question 31

What muscle makes hairs stand up?

Answer 31

Arrector pili muscle

Question 32

What is the arrector pili muscle innervated by?

Answer 32

Sympathetic nervous system

Question 33

Where are sweat glands found?

Answer 33

Superficial hypodermis

Question 34

What type of secretion do sweat glands use?

Answer 34

Merocrine secretion

Question 35

2 types of sweat glands

Answer 35

- Eccrine - Apocrine

Question 36

Where do eccrine sweat glands secrete?

Answer 36

Directly onto skin surface

Question 37

Where do apocrine sweat glands secrete?

Answer 37

Into hair follicles