integamentry system Flashcards
layers of the skin
epidermis
dermis
hypodermis
epidermis
outermost layer
made of many layers of tightly packed epithilial cells
keratnised, stratified, squamous epithilium
avascular
mitosis occurs
dermis
middle layer
dense irregular ct layer with collagen fibres- tensile strength
a dense connective tissue
with good blood supply
sensory receptors
hair follicles grow from hear
sweet and oil glands are here
hypodermis
lowest layer
adipose tissue, areolar connective tissue to store lipids
insulation
epidermal cells
90 percent are keratincytes
tough protein
protection
lamellar granules= water proof and prevent microbes entering making it intact skin
melanocytes= produce skin pigments protect DNA from uv damage
as cells dies in epirderimis
they flattern and move towards the top
dermis cells
fibroblast- cells produce connective tissue// secrete background matrx
phagocytes in this cell- macrophage
adipose tissue- store lipids
functions of integamentry system
REGULATES BODY TEMPERATURE:
vasodilation, insulation, piloerection of hair
STORAGE:
lipids// blood in capilaries
DETECTS SENSATION:
thermoreceptors, mechanoreceptors ( touch ), nociceptors (pain receptors)
PROTECTION:
abrasion ( intact skin ), melanocytes protect against UV
SYNTEHSIS OF V D3
EXCRETES AND ABSORB
ex- salt, water, oil, sweet for lub
ab- medication lipid soluble
syntehsis of VD3
Synthesis of vitamin D3 by UV light – activated to calcitriol by liver enzymes for multiple body functions e.g. absorption of calcium and phosphorous from the GIT and protection against cancer development.
accessory structures
hair
nails
sweet glands
sebacous glands
haemaglobin pigmentation
hair
non living made from proteins
keratin
Contraction of arrector pili muscles (autonomic) – hairs upright (causing goose bumps).
protection UV// entering of pathogens
NAILS
keratinised cells
Protects exposed/distal tips of digits.
Helps digit withstand distortion/counter pressure when subjected to mechanical stress.
Allows manipulation and grip of small objects.
Allows scratching and grooming of the body.
sweet glands
apocrine
Activated at puberty.
Secrete sweat into hair follicles; odour since bacteria use it for nutrition.
merocrine:
secrete straight to skin
Cools skin surface to reduce body temperature; excrete water, electrolytes and some drug metabolites; dilutes harmful chemicals on skin; discourages microbial growth by flushing off skin or via dermcidin.
sebacous glands
Inhibits bacterial growth; lubricates and protects keratin of the hair shaft.
skin colour
Melanin: brown, yellow-brown to black; protects against UV damage.
Carotene: orange-yellow; stored in epidermis; also stored in fat/adipose cells; can be converted to Vitamin A, needed by the retina.
nociceptors
pain
Respond to extremes of temperature, dissolved chemicals including those released by damaged cells, physical damage, infection, inflammation, ischaemia.
thermoreceptors
Free nerve endings in dermis
mechanorecptors
Free nerve endings sensitive to touch & pressure between epidermal cells.
Hairs: nerve endings of root hair plexus.
Merkel cells/Tactile discs: extremely sensitive fine touch & pressure receptors in basal layer of epidermis, with very small receptive fields.
Tactile corpuscles in dermis reticular layer; detect fine touch & pressure.
Lamellated corpuscles: deep pressure and pulse vibration receptors.
Ruffini corpuscles: dendrites intertwined with collagen fibres detect distortion and excess stretch in the dermis and hypodermis.
age effects
epidermis things= increased risk of skin tear, infection and injury.
Dendritic/Langerhans cell number drops= increase skin infection
Vitamin D3 production drops = increase risk of fracture osteomalasis- soft bones
Gland secretion drops – dry, possibly scaly skin and decreased sweat production – reduction in heat loss ability.\
Hair follicles reduce function – finer, thinner hairs. Due to drop in melanocyte function, hairs turn grey/white.
merkel cells
Detects fine touch and is located in the epidermi
ruffini corpsals
Detects tension and distortion of the dermis
tactile corpsules
Located in dermal papillae it detects low frequency vibration, light touch and pressure
