Structure and function

Question 1

What cells compose the epidermis?

Answer 1

• Epithelial cells

- Stratified cellular epithelium

Question 2

Where is the dermis found?

Answer 2

• Beneath the epidermis

- connective tissue

Question 3

What is the subcutaneous fat involved in?

Answer 3

• thermoregulation

Question 4

What do melanocytes produce?

Answer 4

• Melanin

- pigment producing

Question 5

Describe Blaschko’s lines?

Answer 5

• Development growth pattern of skin, not following neves or vessels
• follows the dermatome map, genetic error?

Question 6

Name some appendages?

Answer 6

• Hair
• Nails
• Glands

Question 7

How many layers think is the basal layer?

Answer 7

• usually 1 cell thick

- cuboidal

Question 8

Explain the prickle cell layer

Answer 8

• found in the epidermis
• keratin producing
• lots of desmosomes

Question 9

Explain the granular layer

Answer 9

• 2 or 3 layers of flatter cells
• high lipid content
• cell nuclei lost

Question 10

What is found in the keratin layer?

Answer 10

• Corneocytes (differentiated keratinocytes)

- regularly replaced

Question 11

What are keratinocytes and where are they found

Answer 11

• form tight junctions with the nerves of the skin, hold everything together
• 90% of epidermal cells

Question 12

What is the name given to the immune cell associated with the skin?

Answer 12

• Langerhans cells

Question 13

What do merkel cells detect?

Answer 13

• Detect pressure changes

- mechanoreceptors

Question 14

Where are merkel cells found?

Answer 14

• basal layer

- between keratinocytes and nerve fibres

Question 15

Merkel cell cancer is associated with what type of infection?

Answer 15

• viral infection

Question 16

Nelson’s syndrome?

Answer 16

• melanin stimulating hormone produced in excess by pituitary

Question 17

What are the name of the muscle associated with the hair follicles?

Answer 17

• arrector pili muscle

- smooth muscle fibres

Question 18

What type of gland secretes into the hair follicle?

Answer 18

• sebaceous gland

- produces sebum

Question 19

What are the 3 phases of hair growth

Answer 19

• anagen (growing)
• catagen (involuting)
• telogen (resting)

Question 20

Explain telogen effluvium

Answer 20

• most common cause of hair loss

- seen in pregnancy due to hormone changes

Question 21

What is the dermo-epidermal junction and its role?

Answer 21

• interface between epidermis and dermis

- role: support, adhesion and to act as a semi-permeable membrane

Question 22

What is found in abundance in the dermo-epidermal junction?

Answer 22

• collagen

Question 23

What is seen when there is a spilt in the dermo-epidermal junction?

Answer 23

• blisters

Question 24

Onion rings on histology?

Answer 24

• pacinian (pressure nerves)

Question 25

When you brush your hair and some hair is see on brush, what stage of growth was that hair in?

Answer 25

- telogen

Question 26

Where are apocrine glands found?

Answer 26

- axillary and anogenital region

Question 27

Where are eccrine glands found

Answer 27

- hands and feet - thermoregulation - no hair follicle involved, straight to epidermis

Question 28

What are some functions of the skin?

Answer 28

- barrier (physical and chemical) - thermoregulation - metabolism and detoxification - immune defence

Question 29

What are the 4 layers of the epidermis from superifical to deep?

Answer 29

- Keratin layer - Granular layer - Prickle cell layer - Basal layer

Question 30

What is the average nail growth daily?

Answer 30

- 0.1mm/day

Question 31

Langerhans cells are _______ in origin?

Answer 31

- mesenchymal (bone marrow)

Question 32

Where are Langerhans cells found?

Answer 32

- Prickle cell layer

Question 33

What lies adjacent to hair follicles?

Answer 33

- Sebacous glands

Question 34

Explain vitiligo?

Answer 34

- An autoimmune condition of melanocytes

Question 35

What is the sheding phase of the hair follice called?

Answer 35

- Telogen phase

Question 36

What are the 3 layers of the nail plate?

Answer 36

- Dorsal - Intermediate - Ventral

Question 37

What protects the nuclear DNA in basal cells?

Answer 37

- Melanin caps

Question 38

Pacinian nerves sense______

Answer 38

- pressure

Question 39

Meisner nerves sense______

Answer 39

- vibration

Question 40

What is the dermo-epidermal junction?

Answer 40

- Interface between the dermis and epidermis | - semi-permeable

Question 41

What gland is responsible for odour?

Answer 41

- Apocrine gland

Question 42

The eccrine gland is under _______ nerve supply?

Answer 42

- sympathetic cholinergic nerve supply

Question 43

What is vitamin D3 stored as in the liver?

Answer 43

- Hydroxycholecalciferol

Question 44

What is hydroxycholecalciferol converted to in the kidney?

Answer 44

- 1,25- dihydroxycholestrol