Integumentary system

Question 1

Where are the layers of the skin

Answer 1

superficial = epidermis
Inner layer = dermis
*Not part of skin, but underneath dermis is the fatty layer of adipose and areolar tissue = hypodermis/ subcutaneous layer of fat

Question 2

Purpose of hypodermis

Answer 2

protect muscle and bones
contain nerves that detect pressure

Question 3

Other name for skin

Answer 3

cutaneous membrane

Question 4

Function of skin

Answer 4

UV protection
physical and chemical barrier to infection
regulation of temperature (sweat)
excretions (sweat, salts, waste products)
sensation (pressure, touch temperature and pain)
produce vitamin D (needed to absorb calcium and phosphorus)

Question 5

What are the four strata of epidermis layer

Answer 5

stratum basale
stratum spinosum
stratum granulosum
stratum corneum

Question 6

What is the fifth layer of skin

Answer 6

Stratum lucidum is the thick layer found between granulosum and corneum layers

Question 7

Where is the stratum lucidum

Answer 7

areas that are susceptible to friction:
Palm
Digits of palmar surfaces
Sole of feet
Digits of the sole of feet

Question 8

What is the stratum basale

Answer 8

highly active epithelial cells constantly dividing - eventually these cells reach the corneum
Contain keratin intermediate filaments
produce: keratinocytes, melanocytes and tactile epithelial cells

Question 9

What is the stratum spinosum for

Answer 9

strength and flexibility

Contain: keratinocytes, melanocytes and dendritic cells, keratin intermediate filaments

Question 10

What is the stratum granulosum for

Answer 10

where keratinocytes undergo apoptosis

Keratohyalin convert keratin intermediate filaments into keratin

Question 11

How does the epidermis access nutrients and oxygen

Answer 11

interstitial fluid surrounds the deeper layers of skin so delivery can occur
This fluids drains away as lymph

Question 12

What are the cells in the corneum like

Answer 12

non nucleated
cytoplasm replaced with keratin (fibrous protein)
dead

Question 13

What cell types are in epidermis

Answer 13

keratinocytes (most of the cells in the epidermis)
melanocytes
dendritic cells
intraepidermal macrophages
tactile epithelial cells (detect touch)

Question 14

Dendritic cells function

Answer 14

phagocytose pathogens and present antigen to T cells to activate them

Question 15

what layer are the intraepidermal macrophages found

Answer 15

stratum basale

Question 16

What is the dermis layer

Answer 16

composed mainly of connective tissue containing collagen and elastic fibres

contain macrophages

Question 17

What is the superficial layer of dermis

Answer 17

Known as the papillary region

areolar connective tissue containing fine elastic fibres

Contain: blood vessels, nerve endings, tactile corpuscles (transmit sensations to CNS)

Question 18

What is the deep layer of the dermis

Answer 18

known as reticular region

dense irregular connective tissue
coarse elastic fibres
bundles of collagen
hair follicles
blood vessels
nerve endings

Question 19

What does the dermis contain

Answer 19

nerve endings
touch receptors
blood vessels
sebaceous glands
sweat glands
hair follicles

Question 20

pigments that cause skin colour

Answer 20

carotene
haemoglobin
melanin

Question 21

What is carotene

Answer 21

precursor of vitamin A

Found in corneum and dermis and hypodermis

Question 22

What are the structure that connect dermal layers to epidermal

Answer 22

dermal papilla

Question 23

What are the accessory structures of the skin

Answer 23

hair
glands
nails
*glands and hair protect the body

Question 24

What is hair

Answer 24

fused dead keratinised epidermal cells
consists of shaft (exposed hair), hair follicle and hair root (starts extending from follicle)

Question 25

what structures are associated with hair

Answer 25

arrector pili sebaceous glands (moistens hair, makes skin more water resistant)

Question 26

what glands secrete sweat

Answer 26

sudoriferous

Question 27

what are eccrine sweat glands

Answer 27

found in most areas of the body, particularly forehead, palms and soles of feet

Question 28

What are apocrine sweat glands

Answer 28

found in armpit, groin and areolae (colour around nipples)

Question 29

How do the secretions of glands protect from infection

Answer 29

sebum contains bactericidal chemicals to kill bacteria Acidic PH inhibits microbial growth

Question 30

Process of epidermal growth and repair

Answer 30

epithelial cells from the basal layer are constantly dividing These cells are pushed up toward skin surface. This means they move further from their blood and nutrient supply. At granulosum, they apoptose (lose nuclei) When they reach surface, they are flat dead and non nucleated. cytoplasm replaced by fibrous keratin

Question 31

what are the epithelial cells in the basal layer like

Answer 31

cuboidal and nucleated

Question 32

wound healing process

Answer 32

haemostasis (blood clot) inflammation proliferation remodelling

Question 33

inflammatory response

Answer 33

injured endothelial and tissue immune cells release prostaglandins and cytokines causes vasodilation and permeability so neutrophils and macrophages can enter wound site

Question 34

proliferation

Answer 34

granulation = fibroblasts lay a matrix of collagen Collagen contracts pulling margins of wound together Angiogenesis (formation of new blood vessels ) supply o2 to repairing cells epithelialisation = epithelial cells migrate from margins of wound until they meet

Question 35

factors that influence wound healing

Answer 35

poor circulation poor nutrition = insufficient protein is insufficient building blocks for cell regeneration. Vitamin C needed for collagen synthesis moisture = infection from bacteria temperature = 37C required for optimum cell activity

Question 36

what is the waterproofing protein in the epidermis

Answer 36

keratin *keratinocytes also produce lamellar granules that decrease water entry and loss

Question 37

How do lamellar granules work

Answer 37

release lipids to inhibit evaporation of water retard entry of water across the skin

Question 38

changes of the skin due to aging

Answer 38

decrease in rate of cell division in basale

Question 39

production of melanin

Answer 39

melanocytes synthesise melanin rom the amino acid tyrosine from the enzyme tyrosinase This occurs in the melanosome melanosomes will then surround nucleus

Question 40

What increases the production of melanin

Answer 40

DNA damage UV light (increases activity of tyrosinase)

Question 41

How does melanin protect against DNA damage

Answer 41

absorb UV light neutralise free radicals that form in skin from UV damage

Question 42

process of synthesising vitamin D

Answer 42

Precursor in skin is activated by UV light Enzymes in liver and kidney modify the activated molecule to produce calcitriol

Question 43

Functions of vitamin D

Answer 43

Enhance phagocytic activity Regulate immune system functions Reduce inflammation

Question 44

what happens to dehydrocholesterol- 7 when it absorbs UV-B light

Answer 44

converted into previtamin D3 It then isomerases into vitamin D3

Question 45

how is 25-dihyrdoxyvitamin D synthesised

Answer 45

in the liver, vitamin D3 (or other vitamin D created from sunlight or diet) is metabolised into 25-dihydrocholesterol vitamin D

Question 46

remodelling

Answer 46

remodelling = new collagen matrix forms in wound bed and vessels disappear

Question 47

What happens to blood flow in different temperatures

Answer 47

High = vessels in dermis dilate so heat evaporates Low = Vessels in dermis constrict so blood flow reduced

Question 48

Melanin