Skin and Sensory Receptors Flashcards
epidermis
outer epithelial layer
protection
basal layers fold to dermal papillae
4/5 layers
dermis
underlying connective tissue
thick, sensation, protection, thermal reg, nerves, blood supply
superficial fascia / hypodermis / subcutis
deep to the dermis is loose connective tissue
adipose
some skin appendages may reach it
thin skin has:
hair follicles
thick skin is:
glabrous - non-hairy, no sebaceous or apocrine glands)
epithelium of epidermis
keratinised, stratified, squamous epithelium
layers of skin from deep to superficial
stratum basale spinosum (prickle cell) granulosum (granular) lucidem corneum (keratin layer)
stratum basale
responsible for constant regeneration
single layer
stratum spinosum
lots of desmosomes which anchor cells to each other
thick tufts of intermediate filament (keratin)
stratum granulosum
lose nuclei and cytoplasmic organelles
keratinisation
lipid rich secretions which act as water sealant
stratum lucidem
thin transparent layer
stratum corneum
layer of dead cells
flattened squames filled with keratin
which layer is absent from thin skin?
stratum lucidem
3 non-epithelial cells
melanocytes
langerhans cells
merkel cells
melanocytes
pigment for skin
langerhans cells
immunological role
merkel cells
mechanoreceptors
basal cell carcinoma affects which layer
basal layer
squamous cell carcinoma affects which layer
granular/keratin layer
malignant melanoma affects which layer
melanocytes in basal layer
which is worst cancer to get?
malignant melanoma
what are warts?
small rough lumps
HPV infection
underlying dermis and hypodermis
features absent from thick skin
hair
sebaceous glands
apocrine sweat glands
involved in development of acne
sebaceous glands produce excess sebum
what are hair follicles?
long thin cylinderical shaft composed of keratin and arranged in an organised manner
function: thermoreg
what are sebaceous glands?
secrete sebum into hair follicle provide waterproofing
what are eccrine glands?
throughout skin
synthesise thin watery liquid
evaporation of sweat reduces body temp
what are apocrine glands?
mainly in axilary and groin regions
no definite function
animal scent production
what are erector pili muscles?
small smooth muscle bindles attached to hair follicles below sebaceous gland
contraction = hair stands up
standing up traps air = insulation
contraction can force sebum up protecting hair
what is supplied sympathetically?
arrector pilli
eccrine (merocrine) - not attached to hair follicle
vessels - sym = contraction
dermis is split into what layers
papillary
reticular
papillary layer
superficial, loosely woven
reticular layer
deeper, thicker, denser layer
the epidermis and dermis interdigiate forming:
epidermal downgrowths: rete ridges
epidermal upgrowths: dermal papillae
first degree burns
only epidermis
second degree burns
epidermis and dermis
third degree burns
all layers of the skin, epidermis, dermis, hypodermis
what is a dermotome?
area of skin supplied by a single spinal nerve
two sub groups of cutaneous sensory receptors
free nerve endings
encapsulated nerve endings
free nerve ending functions
nocireceptors
thermoreceptors
mechanoreceptors
some associated with Merkel cells - basal layer
Merkel cell-neurite complexes act as mechanoreceptors to respond to pressure
encapsulated nerve endings
mechanoreceptors - meissners, pacinian, ruffiani
merkel cell-neurite complex
basal layer epidermis
slow
sustained touch/pressure
pacinian corpuscle
deep in hypodermis -sole of feet
deep pressure or rapid vibration
rapid
meissner’s corpuscle
dermal papillae of skin - fingertips, nipples, eyelids
rapid
changes in texture, pressure and vibration
ruffini
dermis layer
slow
stretching, sheering
