Skin Flashcards
epidermis layer
- top skin layer
- dead skin cells
- no blood vessels
- keratinocytes
dermis layer
- vascular
- protein fibres for strength
hypodermis
- adipose tissue
- subcutaneous
- insulation
layers of epidermis
- stratum corneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum basale
stratum corneum
- loosely packed
- horny cells
- strip taking procedure
stratum lucidum
only in thick skin, adds extra rigidity to the epidermis
stratum granulosum
- contains granules that encourage dehydration of the cell
- forms the first barrier of the skin
stratum spinosum
- contains desmosomes which make it spiny shaped when they dry out
stratum Basale
- columnar cells that differentiate to push up the epidermis cells above to create the keratinocyte conveyor
epidermal ridge
the invaginations that the columnar and spinosum cells form in the epidermis to meet with the dermal papilla of the papillary layer
different epithelial cell types
- can be simple or stratified
- squamous
- columnar
- cuboidal
layers of dermis
- papillary and reticular layers
functions of skin
- protection
- thermoregulation
- produces melanin
- produces keratin
- stores lipids
- produces vitamin D
- detects touch and other stimuli
what are the 6 things that happen to our skin when we age?
- skin thinning
- slow repair
- dry skin
- impaired cooling
- lost pigmentation
- lost hair
how does smoking make you look older?
damages elastin and collagen fibres in the dermis layer
what does melanin do?
is a pigment that absorbs UV light and protects cells from UV damage
melanocytes
produce melanin and sit in the stratum basale
melanosomes
vesicles that carry melanin to the epidermal cells from the melanocytes
rickets
a vitamin D deficiency caused by a lack of exposure to UV radiation that leads to depleted calcium production
moles
clusters of melanocytes that can over-proliferate if exposed to too much sun
freckles
melanocytes overproducing melanosomes, and overproduction can occur if a person is exposed to the sun a lot
basal cell carcinoma
more common form of skin cancer that originates in the stratum Basale and doesn’t move around body too much
malignant melanoma
skin cancer caused by overproduction of melanocyte cells and is highly metastatic
tattoo
the artificial pigmentation of the skin that penetrates the dermis layer
hair is made up of the
hair shaft, hair follicle, arrector pili muscle and sebaceous gland
hair shaft
the actual hair part that comes out of the skin
hair follicle
part of the hair in the dermis
arrector pili muscle
connected to the sensory receptors to cause the hair to stand up when the body is cold or when activating the fight or flight response
sebaceous gland
secretes sebum onto the hair shaft which acts as a natural water repellent and moisturiser
where do we have more sebaceous glands
head and shoulders because these are the areas exposed to more water, so we need more protection
acne
caused by blocked hair follicles - mostly on face and shoulders
two types of sweat glands
eccrine and apocrine sweat glands
eccrine glands
- all over the body
- have a duct that empties out onto the skin
- controlled by sympathetic cholinergic nerves which release Ach onto the mAChRs which cause sweating
- have some beta-1 receptors too that are sensitive to NO and adrenaline that cause sweat release when our fight or flight response is activated
apocrine glands
deeper in the skin and secretes more specialised liquids to the base of the hair follicles like pheromones
nails functions
- to protect the fingertips
- to enhance sensation and help detect finer vibrations
free nerve endings receptors
- most common receptor in the skin
- detects temperature, painful stimuli, some movement and pressure, itchiness, detecting the bending of hairs
tactile (Merkel) discs
- are free nerve endings found in the stratum basale
- involves serotonin for communication
- found in fingertips and small receptive fields
- most sensitive to textures, fine touches and pressure
tactile (Meissner) corpuscles
- found in the papillary layer of the dermis
- found in hairless areas like lips, eyelids, nipples
- detect fine touches, movement of objects over skin, light pressure and low frequency vibrations
lamellar (Pacinian) corpuscles
- in the dermis and hypodermis
- detect deep pressure and vibrations
bulbous corpuscles (Ruffini’s endings)
- dermis and hypodermis
- deep pressure, heavy prolonged touch
- found in joints to stop joint rotation (proprioception)
- around fingertips, so may be involved with grip
blood supply in the skin
arteries go up to the capillary loops in the dermis, which then drains down to venus plexus
precapillary sphincters
bands of smooth muscle before the capillary beds that regulate blood flow to the skin
alpha-1 receptors
- part of the sympathetic system and receive NO
- type of gene protein coupled receptor (GPCR) which then activates a 2nd messenger and increases calcium levels in muscle cells to allow for more cross-bridge formations and more contractions
reducing the sympathetic system activity causes _______ of the blood vessels which _______ (incr/decr) blood flow
vasodilation; increases
sympathetic cholinergic nerves
activated by the sympathetic system, so should involve NO but instead uses Ach hormone, and activate the eccrine sweat glands for thermoregulation
radiation
- highest heat loss
- emitting radiation
evaporation
- heat loss via liquids eg sweating and the fluid from breath
- used in really hot climates because other heat loss methods wouldn’t work
convection
- heat loss by hot air replacing cold air through a conc gradient
- affected by wind and water which take our warmth away quickly
conduction
- when a warm object is in contact with a cold object and transfers its heat
core body temperature
37 degrees C
what happens if the heat gain centre is activated?
- decreases activation of a1 receptors to dilate blood vessels
- sympathetic cholinergic activation of eccrine sweat glands to increase sweating
- respiratory rate will increase
- behavioural changes
what happens if the heat gain centre is activated?
- vasoconstriction of blood arteries in skin to prevent blood travelling to the superior areas of the body
- shivering activated
- adrenaline release in the SNS causing increase in cell metabolism for energy
- brown fat in infants broken down for releasing heat
- increase in BMR in sustained cold environments
- hairs stand up to trap insulating air around body
first degree burns
- only affect the epidermis
- leaves no blisters and usually heals pretty quickly
second degree burns
- removes epidermis and some of the dermis
- might leave white, waxy areas and lose some tactile receptors
third-degree burns
- will go into the subcutaneous tissue or even bones
- hard, dry, black, no pain because all pain receptors are lost
- can lead to dehydration, infections and hypothermia
rules of 9s
splits the total body surface area into sections to work out how to help with the burns
