Skin physiology Flashcards
What are the 5 types of skin located nerve endings
Free nerve endings
Tactile disk
Tactile corpuscle
Bulbus corpusle
Lamellar corpuscle
Descibe the phyiology of free never endings
Location: Dermis + epidermis
Design: small swellings of axon terminal = sensory terminals.
Sensation: temp, pain, pressure, movement
Other: Wraps around hair folicales as touch receptors (root hair plexus)
- some chemically activated (hisamine) some Na activated
Descibe the phyiology of tactile disk
Location: top layer of the dermis
Design: associated with merkle cells communication via epithelia and nervous through seritonin
Sensation: Light touch, pressure sharpe edges, texture, 5-15Hz
Other: Common in areas of small receptive feilds
Descibe the phyiology of tactile corpuscle
Location: papilary
Design: nerve endings wrapped in modified shwann cell + connective tissue outer layer
Sensation: delacate touch, light pressure 15-50 Hz
Other: common in hairless regions
Descibe the phyiology of lamellar corpuscle
Location: Deep in dermis + hypodermis
Design: 1 nerve ending wrapped in concentric layers of collagen, between layers intersitial fluid - alongside specilised fibroblasts
Sensation: Deep pressure only breif
Other: Inner rings fold out quickly short stimulus
Descibe the phyiology of bulbus corpuscle
Location: Deep in dermis + subcutanous fats
Design: nerve endings wrapped in core of collagen surrounding structure
Sensation: deep pressure long time
Other: Located in joint capsual for proprioception (angle infomation)
What are Na ion channels of free nerve endings called
TRP channels
how does blood flow around the subpapilary plexus
arterys carry blood whcih travels up into the epidermis then loops down again draining into veins. loops have pre capilary sphinters to control blood flow. and vascular smooth muscle around the vessles
What triggers the contraction of vascular smooth muscle
Noradrenline is released due to SNS activation-
acts on the alpha 1 adernergic receptor
GPCR 2nd messanger -> increases intracellular Ca++ -> constriction -> lowered blood flow
What are the methods of heat loss
evaporation
convection
conduction
radiation
How is heat systems controled
By the hypothalomus having a heat loss and heat gain center which can regulate the body to lose heat when above set point or gain heat when below set point
How can the body gain heat
non shivering thermogenisis
shivering thermogenisis
thyroxine
arrector pili muscle
countercurrent exchange
how can the body increase heat loss
Feedforward
decrease SNS activation of alpha 1 = vasodilation
increase SNS cholinergenic activation of mAChRs lead to increased eccrine gland sweat production
increased respiritory rate
What is the name of small unmyelinated axons of free nerve fibers
+ what are A delta fibers
C-fibers
Smill diameter myelinated axons
What are three pathologys of skin burns (worse than first degree)
Hypothermia
sepsis + infection
dehydration + hypovalemic shock
