Integument Physiology Flashcards
INTEGUMENTARY FUNCTIONS; protection
- Physical: fat, collagen & keratin
- Radiation: melanocytes
- Epidermal Organs: horns, claws
INTEGUMENTARY FUNCTIONS:
immune defence
- Physical barrier to infection
- Immune cells in skin
- Antimicrobial properties in skin gland secretions
INTEGUMENTARY FUNCTIONS:
sensing environment
- pressure receptors
- stretch receptors
- pain receptors
- heat receptors
- cold receptors
- tactile hairs
- toruli tactiles
INTEGUMENTARY FUNCTIONS:
thermoregulation
- sweating
- hairs, piloerection &arrector pili
-blood flow to skin
-insulation by fat
INTEGUMENTARY FUNCTIONS:
storage and excretion
-fat stores energy, water and vitamins
- glands can excrete water and electrolytes
INTEGUMENTARY FUNCTIONS:
communication
- smelly substances from glands
- epidermal organs
- raising of hairs; arrector pili
- pigmentation (melanocytes)
INTEGUMENTARY FUNCTIONS:
selective permeability
- impermeable to water; maintain osmotic balance
- some medications can be absorbed through skin
- some species use skin for gas exchange
Types of mechanoreceptor
- RUFFINI’S END ORGAN: skin stretch
- KRAUSE END BULB: cold
- MEISSNER’S CORPUSCLE: change in texture or slow vibrations
- PACINIAN CORPUSCLE: pressure or fast vibrations
- MERKEL’S DISC: free nerve ending with discoid terminals- sustained touch & pressure
Nociceptors
Free nerve endings can act as nociceptors for pain
Thermoreceptors
Free nerve endings can act as thermoreceptors for hot and cold
Electrolyte homeostasis
- Electrolytes impact water balance and blood acidity
- Electrolytes are lost in sweat
- Water conc. is detected by osmoreceptors in the hypothalamus
Pyrexia
Reset of the hypothalamic set point to a higher temperature, enhances leucocyte function in immune response
Non-shivering thermogenesis
-Increased heat production via increased metabolism
- Caused by…
-Increased thyroxine secretion
-Increased sympathetic (ANS) activity; noradrenaline
-Increased metabolism of lipids caused by adrenaline
Brown adipose tissue
- Predominantly in neonates
- Higher density of mitochondria
- Mitochondria close to lipid stores causes rapid transfer of stored energy into heat energy
How is heat lost?
-RADIATION: body is warmer than surroundings; emission of infrared
-CONDUCTION & CONVECTION: from body surface to cooler object
-EVAPORATION: heat is transferred as water is evaporated from body
