Physiology

Question 1

What is the largest organ in the body?

Answer 1

Skin

Question 2

What is the outermost layer of skin called?

Answer 2

Epidermis

Question 3

Which type of epithelium makes up epidermis?

Answer 3

Stratified squamous epithelium

Question 4

Which layer of skin is deep to epidermis?

Answer 4

Dermis

Question 5

Which tissue type makes up dermis?

Answer 5

Connective tissue

Question 6

Which germ layer forms epidermis?

Answer 6

Ectoderm (forms periderm)

Question 7

Which germ layer forms dermis?

Answer 7

Mesoderm

Question 8

In foetal skin development, which layers are formed after 16 weeks?

Answer 8

Keratin layer + granular layer
Prickle cell layer
Basal layer
Dermis

Question 9

Which cell makes up 95% of epidermis?

Answer 9

Keratinocytes

Question 10

The basal layer of skin is highly metabolically active. True/False?

Answer 10

True

Lots of intermediate filaments

Question 11

Name 3 other epidermal cells (other than keratinocytes)

Answer 11

Melanocytes
Langerhans cells
Merkel cells

Question 12

Where do melanocytes derive from?

Answer 12

Neuronal cell crest

Question 13

What are melanocytes? Which layer of skin are they found?

Answer 13

Pigment-producing dendtritic cells

Basal layer

Question 14

What do melanocytes do?

Answer 14

Convert tyrosine to melanin pigment and load colour onto adjacent keratinocytes

Question 15

Eumelanin is brown/red

Answer 15

Brown

Question 16

Phaeomelanin is brown/red

Answer 16

Red

Question 17

Which disease results due to loss of melanocytes?

Answer 17

Vitiligo

Question 18

Where do Langerhans cells derive from?

Answer 18

Bone marrow

Question 19

What are Langerhans cells? Which layer of skin are they found?

Answer 19

Antigen-presenting cells

Prickle cell layer

Question 20

What are Merkel cells? Where are they found?

Answer 20

Mechanoreceptors that aid sensation

Between keratinocytes + nerve fibres

Question 21

What are the 3 phases of growth of a hair follicle?

Answer 21

Anagen (growing)
Catagen (curve inwards)
Telogen (resting)

Question 22

What is the dermo-epidermal junction (DEJ)?

Answer 22

The interface between the dermis and epidermis

Question 23

List 2 key roles of the DEJ

Answer 23

Support, anchoring, adhesion and growth of epidermal cells

Semi-permeable membrane acts as a filter/barrier

Question 24

Give an example of inherited skin fragility as a result of mutation to one of the proteins in the DEJ

Answer 24

Epidermolysis bullosa complex in young infants

Question 25

Give an example of acquired skin fragility

Answer 25

Dermatitis herpetiformis | Bullous pemphigoid

Question 26

What do fibroblasts in the dermis produce?

Answer 26

Procollagen (becomes collagen) | Elastin

Question 27

The blood vessel supply to skin is greater than its metabolic need. True/False?

Answer 27

True

Question 28

Which nerve receptors sense pressure in skin?

Answer 28

Pacinian corpuscles

Question 29

Which nerve receptors sense vibration in skin?

Answer 29

Meissners corpuscles

Question 30

What do free nerve endings provide sense for in skin?

Answer 30

Temperature | Pain

Question 31

Which inherited condition arises due to overgrowth of nerve endings?

Answer 31

Neurofibromatosis

Question 32

List the 3 main secretory glands in skin

Answer 32

Eccrine Apocrine Sebaceous

Question 33

Eccrine glands secrete ? Apocrine glands secrete ? Sebaceous glands secrete ?

Answer 33

Eccrine glands secrete sweat Apocrine glands secrete odourous fluid Sebaceous glands secrete moisturiser

Question 34

Which areas of the body have a high concn of sebaceous glands?

Answer 34

Head, neck and chest

Question 35

What is the significance of the melanin cap on basal cells?

Answer 35

Absorbs UV rays to protect DNA in the cells' nuclei

Question 36

Which vitamin does skin metabolise?

Answer 36

Vitamin D

Question 37

20% of thyroxine conversion to triiodothyronine (T4 to T3) is done in peripheral tissues such as skin. True/False?

Answer 37

False | 80%!

Question 38

Which cells help protect skin from UV rays?

Answer 38

Melanocytes

Question 39

Ratio of melanocytes : basal cells = ?

Answer 39

1:10

Question 40

Where is the papillary dermis found?

Answer 40

Uppermost layer of the dermis