the skin 1

Question 1

What is a keratinocyte?

Answer 1

keratinised squamous cell

Question 2

What is a melanocyte?

Answer 2

melanin producing cell

Question 3

What is the epidermis?

Answer 3

superficial layer of keratinocytes

Question 4

What is the dermis?

Answer 4

deeper layer of connective tissue and skin appendages

Question 5

What are exocrine glands?

Answer 5

glands with ducts or secretion onto surfaces

Question 6

What are endocrine glands?

Answer 6

glands secreting directly into blood

Question 6

What are glands formed from?

Answer 6

specialised cuboidal/columnar epithelial cells

Question 6

What are the types of exocrine secretion?

Answer 6

• merocrine
• apocrine
• holocrine

Question 6

Describe merocrine secretion

Answer 6

• exocytosis via vesicles
• no damage to cell itself

Question 6

Describe apocrine secretion

Answer 6

• apical part of cell accumulates secretion and then pinched off
• cell survives

Question 7

Describe holocrine secretion

Answer 7

• rupture of cell membrane
• cell dies and becomes secretory product

Question 8

What are cytokeratins?

Answer 8

intermediate filaments of epithelia

Question 9

What are the 3 layers of skin?

Answer 9

• epidermis
• dermis
• subcutaneous adipose tissue

Question 10

Describe the epidermis

Answer 10

• epithelium
• ectodermal origin

Question 11

Describe the dermis

Answer 11

• connective tissue
• mesodermal origin

Question 12

What is the Meissner corpuscle for?

Answer 12

fine touch sensation

Question 13

What is the Pacinian corpuscle for?

Answer 13

vibration sensation

Question 14

What is hairless skin called?

Answer 14

glabrous skin

Question 15

Which 5 layers compose the epidermis?

Answer 15

• horn cell layer
• granular cell layer
• prickle cell layer
• basal cell layer

Question 16

What are the 5 layers of the epidermis each for?

Answer 16

• horn cell layer (waterproofing)
• granular cell layer (filaggrin)
• prickle cell layer (mechanical strength)
• basal cell layer (replenishing)

Question 17

What cell types are found in the epidermis?

Answer 17

• keratinocytes
• melanocytes
• langerhans cells
• merkel cells

Question 18

What are langerhans cells for?

Answer 18

immune function (sentinel cells)

Question 19

What are merkel cells for?

Answer 19

sensory function (light touch)

Question 20

Why are cytokeratins important in diagnosis

Answer 20

individual organs have very specific cytokeratins (so do immunohistochemistry on malignant cells and you can tell where they are from)

Question 21

What is the largest organ of the body?

Answer 21

skin

Question 22

What percentage of bodyweight is skin, and how many kilos?

Answer 22

• 5kg
• 15% of bodyweight

Question 23

What surface area does skin cover?

Answer 23

2 m^2

Question 24

Where do you find glabrous, hairless skin?

Answer 24

• fingers
• palms
• toes
• soles
• lips
• labia minora
• glans penis

Question 25

What is the epidermis composed of?

Answer 25

keratinocytes undergoing terminal differentiation

Question 26

What is at the junction between the epidermis and dermis?

Answer 26

basement membrane (collagen layer)

Question 27

What kind of epithelium is found at the epidermis?

Answer 27

keratinising stratified squamous epithelium

Question 28

How can you recognise squamous desmosomes?

Answer 28

they have prickles

Question 29

How do melanocytes deliver melanin?

Answer 29

delivers melanin to 36 keratinocytes via dendrites