Physiology - Dermatology

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 the epidermis?

Answer 3

stratified squamous epithelium

Question 4

which layer of skin is deep to the epidermis?

Answer 4

dermis

Question 5

which tissue type makes up the dermis?

Answer 5

connective tissue

Question 6

which germ layer forms the epidermis?

Answer 6

the ectoderm

forms the periderm that becomes the skin

Question 7

which germ layer forms the dermis?

Answer 7

the 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 most of the epidermis?

Answer 9

keratinocytes

Question 10

true or false: the basal layer of the skin is metabolically active

Answer 10

true

contains lots of intermediate filaments

Question 11

name three epidermal cells

Answer 11

melanocytes
langerhans cells
merkel cells

Question 12

where are melanocytes derived from?

Answer 12

the neural crest

Question 13

what are melanocytes?

Answer 13

pigment producing dendritic cells

Question 14

what layer of skin are melanocytes found in?

Answer 14

the basal layer

Question 15

what do melanocytes do?

Answer 15

convert tyrosine to melanin pigment and load colour onto adjacent keratinocytes

Question 16

what colour is eumelanin?

Answer 16

brown

Question 17

what colour is pheomelanin?

Answer 17

red

Question 18

which disease is caused by loss of melanocytes?

Answer 18

vitiligo

Question 19

where are langerhans cells derived from?

Answer 19

bone marrow

Question 20

what are langerhans cells?

Answer 20

antigen presenting cells

Question 21

where are langerhans cells found?

Answer 21

the prickle cell layer of the skin

Question 22

what are merkel cells?

Answer 22

mechanoreceptors that aid sensation

Question 23

where are merkel cells found?

Answer 23

between keratinocytes and nerve fibres

Question 24

what are the three phases of growth of a hair folicle?

Answer 24

anagen
catagen
telogen

Question 25

what is the dermo-epidermal junction?

Answer 25

the interface between the dermis and the epidermis

Question 26

give an example of an inherited skin fragility caused by a mutation in a protein in the DEJ

Answer 26

epidermolysis bullosa complex in young children

Question 27

give two examples of acquired skin fragility

Answer 27

dermatitis herpetiformis | bullous pemphigoid

Question 28

what do fibroblasts in the dermis produce?

Answer 28

procollagen | elastin

Question 29

what does procollagen become?

Answer 29

collagen

Question 30

true or false: the blood vessel supply to skin is greater than its metabolic need

Answer 30

true

Question 31

which nerve receptors sense pressure in the skin?

Answer 31

pacinian corpuscles

Question 32

which nerve receptors sense vibration in skin?

Answer 32

meissner's corpuscles

Question 33

what do free nerve endings provide sense for in the skin?

Answer 33

temperature | pain

Question 34

which inherited condition arises due to overgrowth of nerve endings?

Answer 34

neurofibromatosis

Question 35

list the three main secretory glands in the skin

Answer 35

eccrine apocrine sebaceous

Question 36

what do eccrine glands secrete?

Answer 36

sweat

Question 37

what do apocrine glands secrete?

Answer 37

odorous fluid

Question 38

what do sebaceous glands secrete?

Answer 38

moisturiser

Question 39

which areas of the body have a high concentration of sebaceous glands?

Answer 39

head neck chest

Question 40

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

Answer 40

absorbs UV rays to protect DNA in the cells nuclei

Question 41

which vitamin does skin metabolise?

Answer 41

vitamin D

Question 42

true or false: 20% of thyroxine conversion to triiodothyronine is done in peripheral tissues such as skin

Answer 42

false 80%

Question 43

which cells help protect the skin from UV rays?

Answer 43

melanocytes

Question 44

what is the ratio of melanocytes to basal cells?

Answer 44

1 to 10

Question 45

where is the papillary dermis found?

Answer 45

the uppermost layer of the dermis