Skin and Integumentary System

Question 1

what are the functions of the integument system?

Answer 1

• protects from: abrasion, infection, UV light, dehydration
• thermal regulation
• sensory reception
• vitamin d production
• communication

Question 2

where is vitamin d produced?

Answer 2

dermis of skin, after exposure to sunlight

function allows calcium to = absorbed from foods you eat

Question 3

the skin is the largest …

Answer 3

organ

Question 4

what 3 layers is the skin divided into?

Answer 4

• epidermis
• dermis
• hypodermis

Question 5

what is a hypodermic needle?

Answer 5

long hollow needle that reaches all the way from epidermis to dermis

Question 6

epidermis

Answer 6

• made up of keratinised stratified squamous epithelium
• gives strength to skin
• has no blood supply, so relies on oxygen absorption + nutrients from dermis blood vessels

Question 7

the nails are made in the ..

Answer 7

epidermis

Question 8

what are the layers of the epidermis?

Answer 8

• stratum corneum (most superficialities layer)
• stratum lucidum (only thick skin)
• stratum granulosum
• stratum spinosum
• stratum basale (deepest layer of epidermis)

Question 9

the stratum basale has 4 types of cells

what are they?

Answer 9

keratinocytes

• makes keratin
• keratin = waterproof + strong

merkel cells
- used as sensory receptors for sense of light touch

macrophages
- ingest debris

melanocytes

Question 10

melanin is produced from the amino acid …

Answer 10

tyrosine

Question 11

eumelanin

Answer 11

• brown and black pigments found in darker people
• small amounts —> blonde/brown hair
• black pigment without brown —> grey hair tint

Question 12

pheomelanin (sulphur containing)

Answer 12

• gives pink to red hue

- abundant in lips, nipples + vagina

Question 13

production of melanin is increased when ..

Answer 13

during pregnancy

Question 14

what is the function of melanocytes (brown)

Answer 14

make and transport melanosomes for several keratinocytes

have long skinny arms to accomplish this

Question 15

which 2 mechanisms can melanosomes be passed onto keratinocytes?

Answer 15

• phagocytosis

- endocytosis

Question 16

tanning

Answer 16

UV light triggers dna damage in keratinocyte nucleus

—> activating p53

regulates expression of gene POMC (proopiomelanocorticon)

Question 17

what is POMC post translationally processed to produce?

Answer 17

melanocyte stimulating hormone (MSH) + beta endorphin

Question 18

the stratum basale is the only layer where..

Answer 18

epidermis cells = dividing

Question 19

what is the stratum spinosum?

Answer 19

old cells that have been pushed up to make the next layer

now attached to each other by desmosomes

cells = alive but don’t divide here

Question 20

what does the stratum spinosome also contain?

Answer 20

langerhan cells (WBC)

Question 21

why do cells in the stratum granulosum start to die?

Answer 21

too far from nutrient source in dermis

Question 22

stratum lucidum

Answer 22

only layer on palm + soles

thin layer —> projection from UV radiation

Question 23

why do dark skinned people have lighter coloured palms and soles?

Answer 23

in palms + soles, stratum lucidum is present

tan coloured protein blocked underlying melanocytes from view

Question 24

what is desquamation?

Answer 24

when cells lose their nucleus + fuse to squamous sheets, which are shed from the surface in 2 weeks

Question 25

in the stratum corneum, the dead cells are filled up with ...

Answer 25

keratin

Question 26

what is keratin?

Answer 26

waxy protein only pound in epidermis

Question 27

what is the secrete ingredient of all moisturises?

Answer 27

water

Question 28

what are the 4 stages in skin healing?

Answer 28

- inflammation - scab formation - cell division + migration - scar formation

Question 29

skin injury + repair step 1

Answer 29

bleeding happens at injury site mast cells in region trigger immune response

Question 30

skin injury + repair step 2

Answer 30

scab forms stratum basale cells migrate along edges of wound phagocytic cells remove remove debris clotting also happens

Question 31

skin injury + repair step 3

Answer 31

scab is undermined by epidermal cells migrating over fibroblast meshwork fibrin clot disintegrates

Question 32

skin injury + repair step 4

Answer 32

scab has been shed + epidermis complete shallow depression marks injury site fibroblasts in dermis continue to create scar tissue —> elevate overlying epidermis

Question 33

what are the 2 types of mechanoreceptor located rose to the surface of the skin?

Answer 33

merkel receptor - fires continuously whilst stimulus present - SLOWLY adapting fibre - responsible for sensing fine details meissner corpuscle - fires only when stimulus first applies + when removed - RAPIDLY adapting fibre - responsible for controlling hand grip

Question 34

what are the 2 mechanoreceptors located deeper in the skin?

Answer 34

Ruffini cylinder - fires continuously - SLOWLY adapting fibre - associated with stretching of skin Pacinian corpuscle - fires when stimulus first applied + when removed - RAPIDLY adapting fibre - associated with sensing rapid vibrations + fine texture

Question 35

what are C fibres?

Answer 35

unmyelinated nerve fibres found in hairy skin sensitive to indentation most active when stimulus moves slowly across skins surface

Question 36

where are cold receptors located?

Answer 36

epidermis

Question 37

where are the warm receptors located?

Answer 37

dermis

Question 38

what are the 3 types of pain?

Answer 38

nociceptive - signals impending damage to skin inflammatory pain - caused by damage to tissues/joints by tumour cells neuropathic pain - caused by damage to central nervous system e.g. brain damage caused by stroke

Question 39

there are more pain receptors in the...

Answer 39

centre of body

Question 40

what are the 2 layers in the dermis?

Answer 40

- papillary layer (more superficial) | - reticular layer

Question 41

papillary layer

Answer 41

- loose connective tissue - has ridges to inc SA for contact with epidermis - forms our fingerprints

Question 42

reticular layer

Answer 42

- dense irregular connective tissue - gives dermis its strength - strongest layer of DERMIS - has lots of collagen + elastin

Question 43

the stratum spinosum is the strongest layer of the..

Answer 43

epidermis

Question 44

the meissner corpuscle nerve receptors in the dermis for...

Answer 44

light touch

Question 45

the pacinian corpuscle nerve receptors in the dermis for ...

Answer 45

vibration and pressure

Question 46

what is the source of collagen for injections?

Answer 46

bovine (cow) porcine (pig) human skin

Question 47

the subcatenous layer - hypodermis

Answer 47

made of loose connective tissue - areolar + adipose stabilises skin position contains many fat cells safely receives hypodermic needles

Question 48

what are the chief parts of the hair?

Answer 48

root - imbedded in skin shaft - projects above skins surface

Question 49

what 3 layers is the hair shaft organised into?

Answer 49

- medulla - central core - cortex - surround medulla - cuticle - outermost layer

Question 50

what is the hair follicle?

Answer 50

root sheath extending from the epidermal surfaces into the dermis

Question 51

what is the papilla in hair follicles?

Answer 51

nipple shaped indentation with blood vessels and nerves

Question 52

what is the matrix?

Answer 52

germinal layer of cells right above papilla

Question 53

what are the functions of hair?

Answer 53

- help maintain warmth - alter body to presence of insects on skin - guarding scalp against physical trauma, heat loss + sunlight

Question 54

each hair is associated with...

Answer 54

- one/more sebaceous (oil) glands - arrector pili muscle - plexus of nerves around root

Question 55

what are the 2 types of sweat (sudoriferous) glands?

Answer 55

merocrine (eccrine) - all over skin apart from nipples apocrine - located only in axillary, pubic and anal regions - larger than merocrine - secretes thicker sweat

Question 56

what is diaphoresis?

Answer 56

sweating with wetness

Question 57

what are the 2 specially modified sweat glands?

Answer 57

ceruminous - found in external ear canal mammary - milk producing glands found in female breast - modified apocrine glands

Question 58

sebaceous glands

Answer 58

occur over all body (except palms and soles) simple alveolar glands holocrine secretion

Question 59

function of the sebum

Answer 59

- softens + lubricates hair and skin - skin waterproofing - collects dirt

Question 60

nails

Answer 60

scale like modification of epidermis made of hard keratin parts of nail: - free edge - body - root - nail folds - eponchyium - cuticle