L49 - Skin anatomy Flashcards
1
Q
What is the integumentary system?
A
barrier between internal organs and the outside environment
2
Q
what is the function of the integumentary system?
A
- protection
- regulation
- sensation
3
Q
what is within the integumentary system?
A
- skin
- cutaneous glands - sebaceous and sweat
- fingernails
- hair
4
Q
What are the skin types?
A
- hairy - tactile sensations, defense
- glabrous (non-hairy) - tactile details
5
Q
what is the function of skin?
A
- protection
- thermoregulation
- humidity control
- produces vit D
6
Q
What is the skin microbiome?
A
- skin’s ecosystem
- disruption can lead to conditions
- another defense mechanism microscopically
7
Q
What is the skin layers?
A
- epidermis
- dermis
8
Q
What is the epidermis like?
A
- stratified epithelium
- no blood vessel supply
- layers (strata) of keratinocytes
- contains melanocytes
- keratin production
9
Q
What are the different layers of keratinocytes?
A
- stratum corneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum basale
10
Q
what is the stratum corneum?
A
- flat, dead keratinocytes, cross linked keratin fibres
- protect against water loss
- loss = weak barrier
11
Q
what is the stratum lucidum?
A
- rows of dead keratinocytes
- only in glabrous skin
- lipid rich = water kept out
12
Q
what is the stratum granulosum?
A
- mature keratinocytes from spinosum
- keratohyalin granules, lamellar bodies
13
Q
what is the stratum spinosum?
A
- mature keratinocytes
- linked by desmosomes
- keratin production
- langerhans cells
14
Q
what is the stratum basale?
A
- deepest layer
- new keratinocytes
- contains melanocytes
15
Q
What are the layers of the dermis?
A
- papillary
- reticular
16
Q
What is the papillary layer like?
A
- loose connective tissue
- elastic fibres
- capillary loops
- nerves
17
Q
What is the reticular layer like?
A
- dense irregular connective tissue
- contain collagen fibres
- elastin
- glycosaminoglycans
18
Q
What are the cells of the dermis?
A
- fibroblasts, keratinocytes - principal cell
- macrophages - assist immune system
- adipocytes - fat cells
- mast cells - inflammatory
- myofibroblasts - contractile cells
- myoepithelial cells - in sweat glands
19
Q
What are keratinocytes like?
A
- change in structure and functions as you move towards outer layer
- mostly keratins
- desmosomes and hemi-desmosomes anchor them
- lamellar granules help form lipid barrier
20
Q
What do desmosomes do?
A
- connect cells via cadherin proteins
- provide strength by linking intracellularly
- loss of connection = issues
21
Q
What do hemi-desmosomes do?
A
- connect keratinocytes to basement membrane via integrin receptors
- contributes to strength
- loss = skin blistering
22
Q
Why is our skin tough?
A
- keratinocytes >x70 stiffer than other cell
- due to cytoskeleton and keratin filaments
23
Q
What does keratin do?
A
- network of fibre, mesh like
- bundles of keratin subunits, wrapped around each other
- provide structural integrity of epidermis
24
Q
What do lamellar granules do?
A
- round/oblong
- produced by keratinocytes
- contain glucosylceramides, lipids, enzymes and other proteins for desquamation
- help form impermeable lipid containing barrier
- abnormalities = skin conditions
25
What do melanocytes do?
- produce melanin
- protect against UV radiation
- support immune system
- in the bottom layer of epidermis
26
What do langerhans cells do?
- contain birbeck granules
- support immune system
- throughout epidermis
27
What do merkel cells do?
- light touch and sensation
- through connection to nerve fibres
28
What do melanocytes do?
- form melanosomes, contain melanin
- transfer them to keratinocytes
- melanosomes form melanin caps
29
what is the epidermal melanin unit?
anatomical relationship between melanocytes and keratinocytes
30
What is hyperpigmentation caused by?
- inc melanin production
- inc num of melanocytes
31
What is hyperpigmentation like in epidermal and dermal?
- too much melanin/melanosomes transferred
- melanin crosses damaged basement membrane
32
What is the treatment for hyperpigmentation?
- photoprotection to prevent new spots
- inhibitors of melanin production
33
What are issues that can be caused by merkel cells?
- inc production = hypersensitivity (allodynia)
- type of neuropathic pain
34
How are langerhans cells involved with immunity?
- interpret external environmental threats
- n/dangerous - coordinate immune tolerance
- dangerous - work with keratinocytes, instruct Tlymp = response
35
What is hair like?
- part of integumentary system
- growth like skin
- shaft, hair root, hair bulb
36
What is the function of hair?
- protection from the sun, trap particulates
- prevents heat loss, sweat from running into eyes
- alopecia and baldness - sensitivity to androgen hormone DHT = less blood flow at hair follicle
37
What do nails do?
- integumentary system
- rich in blood vessels
- lunula crescent shap, nail fond anchors
- protective, experience max mechanical stress
- changes in shape can be a symptom of smth else
38
What re the different glands?
- exocrine - via duct
- sudoriferous, sebaceous, ceruminous, mammary
39
what are the different exocrine gland structures?
- simple - single duct
- compound - multiple, branched ducts
40
what are the different exocrine gland secretion methods?
- merocrine - exocytosis
- apocrine - cell mem buds off into duct
- holocrine - cell mem ruptures to release
41
What are the different types of sudoriferous glands?
- eccrine - onto surface of skin
- apocrine - into hair follicles
42
what do oil producing glands do?
release sebum into follicular duct
43
What is the purpose of sebum?
- coats and moisturises
- protects skin
44
What is a holocrine gland?
contains part of ruptured cell
45
What are ceruminous glands?
- modified apocrine gland
- in external auditory canal
- produce cerumen
- protective role, trap and take particulates
46
What are mammary glands?
- apocrine gland
- produce milk on either side of the front of the chest wall
47
What are the different sensory receptors in the skin?
- mechanoreceptors - physical change
- thermoreceptors - temp change
- nociceptor - pain
48
what are the different types of mechanoreceptors?
- hair - light touch
- meissner's corpuscle - indents, slipping
- pacinian corpuscle - vibrations
- merkel's disk - texture
- ruffini corpuscle - stretch
49
How do thermoreceptors work?
- cold, warm receptors
- opposite receptor stops discharging at temp change
- ions pass through due to heat
50
How do nociceptors work?
- pain related to pressure, temp and chems
- signals when tissue damage occurs
- transient receptor potential ion channels
- Adelta - temp, pressure, chem
- C - thermal, mechanosensitive pain
51
How is technology involved with skin?
exploiting full definition of integumentary system to develop artificial skin that redefines how we think of skin
