week 19 (skin) the integumentary system

Question 1

what is the largest organ in the human body

Answer 1

skin

Question 2

name some key roles the skin plays

Answer 2

protection from external environment
sensory
absorption (IV = vit D synthesis)
secretion (sweat, electrolytes, sebaceous oils, pheromones)
body temperature regulation (high surface area to body volume)
body reservoir
aesthetics

Question 3

how many layers are there in the skin

Answer 3

3

Question 4

what are the three layers of the skin (outer to innermost

Answer 4

epidermis
dermis
hypodermis

Question 5

name 4 characteristics of the epidermis

Answer 5

outermost layer
epithelial
non vascular
protective

Question 6

name 5 characteristics of the dermis

Answer 6

fibrous connective tissue
epithelial gland structures (sweat and sebaceous glands)
smooth muscle
vascular
sensory

Question 7

what type of tissue is the dermis

Answer 7

fibrous connective tissue

Question 8

what are the 2 epithelial gland structures in the dermis

Answer 8

sweat glands
sebaceous glands

Question 9

which of the three layers in the epithelial system is not actually skin

Answer 9

hypodermis

Question 10

name 4 characteristics of the hypodermis

Answer 10

not skin
protective
adipose and loose
connective tissue

Question 11

structure of epidermis is composed of what kind of epithelium

Answer 11

thick keratinised squamous epithelium

Question 12

how many layers are there in the epidermis

Answer 12

5

Question 13

in the epidermis, it is consisted of how many epithelial cell types

Answer 13

4

Question 14

what are the 5 layers in the epidermis (innermost to outermost)

Answer 14

stratum basale
stratum spinosum
stratum granulosum
stratum lucidum
stratum corneum

Question 15

what are the 4 cell types in the epidermis

Answer 15

keratinocytes
melanocytes
Langerhans cells
merkel cells

Question 16

in the stratum basale what occurs

Answer 16

cells divide by mitosis and some of the newly formed cells become the cells of the superficial strata

Question 17

what occurs in the stratum spinosum

Answer 17

keratin fibres and lamellar bodies accumulate

Question 18

what occurs stratum granulosum

Answer 18

keratohyalin and a hard protein envelope form; lamellar bodies release lipids and die

Question 19

what is the envelope that is formed in the stratum granulosum (within the epidermis) composed of

Answer 19

keratohyalin and a hard protein envelope

Question 20

in the stratum lucidum what do the dead cells contain

Answer 20

dead cells containing dispersed keratohyalin’s

Question 21

what occurs in the stratum corneum

Answer 21

dead cells with a hard protein envelope - the cell contain keratin and are surrounded by lipids

Question 22

in the epidermis, what is the role of keratinocytes

Answer 22

produce keratin and are the primary cell os epidermis

Question 23

keratinocytes are the key cell involved in what

Answer 23

wound healing

Question 24

keratinocytes are connected by what

Answer 24

desmosomes

Question 25

filaggrin causes keratin fibres to what

Answer 25

dimerise (keratinisation)

Question 26

what protein causes keratin to dimerise (keratinisation)

Answer 26

filaggrin

Question 27

mutations in profilaggrin cause what condition

Answer 27

eczema

Question 28

in the epidermis, the granule layer is composed of what 3 types of keratin

Answer 28

1, 2, 10

Question 29

in the spinous layer, as cells grow upwards, they express what enzyme to cross link junction complexes

Answer 29

transglutaminases

Question 30

in the spinous layer, as cells grow upwards they express transglutaminases which does what

Answer 30

cross link junction complexes

Question 31

in the cornified layer within the stratum corneum, cells die and the cornified layer forms. Fillagrin is hydrolysed to what

Answer 31

amino acids

Question 32

in the cornified layer within the stratum corneum, cells die and the cornified layer forms. Fillagrin is hydrolysed amino acids which form what

Answer 32

a protective water proof barrier

Question 33

in the epidermis, what is the role of melanocytes

Answer 33

produce pigment - melanin

Question 34

where are melanocytes located

Answer 34

stratum basale

Question 35

what are merkel cells

Answer 35

neuroepithelial cells associated with sensory nerve ending

Question 36

what do merkel cells act as

Answer 36

mechanoreceptors

Question 37

what neurotransmitter are used by merkel cells

Answer 37

glutamate

Question 38

what are merkel cells sensitive to

Answer 38

shear and pressure

Question 39

where are langerhan's cells made (and where do they migrate to)

Answer 39

bone marrow and migrate to epidermis

Question 40

how do langerhans cells function

Answer 40

as macrophage like antigen presenting cells (activate T cells)

Question 41

how is melanin synthesised

Answer 41

tyrosinase conversion of tyrosine through multiple reactions to o-Quinone and ultimately melanin

Question 42

when melanin is converted from tyrosinase where does this occur

Answer 42

melanocytes

Question 43

in what step in melanin synthesis decides if you are black/white

Answer 43

dopaquinone (lack of enzymes)

Question 44

in melanin synthesis production of eumelanin ends in what colour

Answer 44

black

Question 45

in melanin synthesis production of pheomelanin end in what colour

Answer 45

red

Question 46

does UVA or UVB have a longer wavelegth

Answer 46

UVA

Question 47

UVA penetrates what layer of the skin

Answer 47

dermis

Question 48

what layer of the skin does UVB causes sunburn and penetrates what layer of the skin

Answer 48

epidermis

Question 49

how is alpha melanocyte stimulating hormone synthesised and released

Answer 49

damaged dermal cells

Question 50

how many transmembrane subunits are there in the MC1R

Answer 50

7

Question 51

MC1R activated MITF transcription factor where

Answer 51

in melanocytes

Question 52

In melanocytes, MC1R activates what

Answer 52

MITF transcription factor

Question 53

where us the alpha melanocyte stimulating hormone produced

Answer 53

dermis

Question 54

the MC1R drives expression of what

Answer 54

tyrosinase, DCT, and TRP1 (favouring eumalanin black synthesis

Question 55

how can you develop carotene

Answer 55

from diet deposited in stratum corneum and fatty tissue of hypodermis as a yellow-orange colour

Question 56

how can you develop erythema

Answer 56

re-direction of blood flow to superficial skin capillaries due to irritation, infection or as part of a response to fever

Question 57

how does blushing occur

Answer 57

catecholamines induced vasodilation which pushes blood to skin surface in well perfused areas of skin

Question 58

how do you develop jaundice

Answer 58

liver disease releases bile pigments to blood which are deposited in the hypodermis and the cornea of the eye giving a yellow colour

Question 59

how does bruising develop

Answer 59

injury to capillaries of dermis and hypodermis results in deposits of bilirubin in skin which cause colours of bruise (blue/orange/green)

Question 60

the strength of the dermis comes what 2 layers

Answer 60

papilary and reticular

Question 61

in what direction is eccrine (merocrine) secreted

Answer 61

exocytosis

Question 62

what does apocrine secrete

Answer 62

lipid, protein, and amino acid laden

Question 63

what skin appendage gland is often waxy

Answer 63

holocrine

Question 64

nails are composed of what

Answer 64

keratin

Question 65

what do nails do

Answer 65

protects tips from damage and aids in precision of movement

Question 66

what are the three phases of hair growth

Answer 66

rest (telogen) growth (anagen) cessation (catagen)

Question 67

how many phases are there in hair growth

Answer 67

3

Question 68

what is hair composed of

Answer 68

keratin

Question 69

what does hair aid in

Answer 69

thermoregulation

Question 70

how many skin glands are there

Answer 70

5

Question 71

what are the 5 types of skin glands

Answer 71

eccrine sweat glands apocrine sebaceous glands ceruminous glands mammary glands