Chapter 5- Integumentary System Flashcards
Integumentary system functions
- regulate body temp
2.stores blood - protection from external environment
- detects sensations
- excretes/absorbs
- synthesize vitamin D
structure of skin
epidermis
dermis
SC layer
Epidermis
epithelial cells, thin, no blood vessels
Dermis
irregular connective tissue, thicker, has blood vessels, collagen and elastic fibers-stretch and recoil easy)
SC layer
anchor point and contains lamellated corpuscles-sensitive to pressure
Epidermis cells
keratinocytes
melanocytes
tactile epithelial
macrophages
Keratinocytes
product keratin, fibrous protein (wet suit), 90%, protection
melanocytes
produce melanin (absorb UV, contribute to skin colour), 8%
tactile epithelial
connects to tactile discs (detect touch), least amount, aka Merkel cells
macrophages
Langerhans cells, immune response, from RBM, against microbes
Skin layers
stratum basale
stratum spinosum
stratum granulosum
stratum lucidum
stratum corneum
Stratum Basale
row of cuboidal keratinocytes/produce keratin/ protects from injury, attaches to hemidesmosome/melanocytes and tactile epithelial cells, stem cells
Stratum Spinosum
can still divide, produce more keratin, (desmosomes hold cells to one another), macrophages and melanocytes present, 8-10 layers
stratum germination
forming new cells or stem cells
stratum granulosum
cells undergo apoptosis, too far from basale layer (no nutrition)
Keratohyalin
keratin filaments into keratin and inside cells are lamellar granules- release fat secretion into EFC
stratum lucidum
found only in thick skin, clear/dead keratocytes cells
stratum corneum
flatten, dead keratocytes cells (no cell parts),
Callus
thickening of SC layers
Dermis regions
Papillary region
Reticular region
papillary region
closest to epidermis (collagen and elastic fibers)
what does the papillary region consists of?
dermal papillary
capillary loops
corpuscles of touch
free nerve ending dendrites
dermal papillary
small, nipple shaped, projects upwards, increases surface area
capillary loops
found in dermal papillary, vascular
corpuscles of touch
nerve ending, sensitive to touch
free nerve ending dendrites
warmth, itching, tickling, no structure
reticular region
extensibility (stretch), elasticity (original shape), attached to SC, fibroblasts & wandering cells, thick collagen fibers
what does the reticular region of the dermis consist of?
blood vessels, nerves, sebaceous glands, sudoriferous glands, occupy spaces between fibers
epidermal ridges
downward projection of the epidermis between dermal papillary and papillary region-fingerprints/footprints, unique to each person, increases surface area
keratinization
cells move through epidermal layers, accumulate more and more keratin, then apoptosis
pigments of skin colour
melanin, hemoglobin, carotene
melanin
product of melanocytes (everyone has same number), colour is how much is produced and transferred to keratinocytes
functions of melanin
absorb UV rays
prevent DNA damage to neighboring cells (like tiny umbrella)
functions of hair
protects head from sun
decrease heat loss from head
protection from foreign particles
sensing light touch
shaft of hair
projects above skin
root of hair
deep in the dermis, deep to hair shaft
hair-medulla
innermost, where pigment granules are
hair-cortex
middle layer
hair-cuticle
outer most layer; keratinized cells
hair follicle
surrounds root, , epithelial root sheath and derma root sheath surrounds hair
hair- bulb
base of hair follicle
papilla of hair
part of bulb, vascular
hair matrix
germinal layer of cell in bulb, hair growth
arrector pili
smooth muscle, autonomic nerves cause contraction = goose bumps
hair root plexus
branches of nerves (dendrites), generate impulse when shaft is move-feel touch
sebaceous oil glands
simple branched acinar, connected to hair follicles/some locations open to surface (lips, penis, labia, eyes), secrete sebum
sebum
mixture of triglycerides, cholesterol, proteins and inorganic salts
sebum functions
coats hairs (prevents drying), regulates evaporation, keeps skin soft, bactericidal
sudoriferous glands
sweat glands through hair follicles or pores on surface of skin
types of sudoriferous glands
eccrine
apocrine
eccrine sweat glands
simple, coiled, tubular glands (more common), located in the deep dermis, mostly water, urea, ammonia, amino acids, glucose and lactic acid
functions of eccrine glands
body temperature regulation (thermoregulation)-thermoregulatory sweating
insensible perspiration
evaporates before it is perceived
sensible perspiration
sees and feel nmoisture on skin
emotional sweating
fear or embarassment
apocrine sweat glands
simple coiled tubular glands, have larger ducts, in armpit, groin, areolae, secretes via exocytosis and opens onto hair follicle, dont function until puberty, appears milky, (bacteria metabolize sweat-musky odor), emotional sweat/sexual activites
ceruminous glands
produce cerumen, secrete on surface or into sebaceous glands, waterproof ear canal/protection, deep to sebaceous glands
cerumen
earwax
nails
tightly packed keratinized cells
parts of the nail
nail body, free edge, nail root, lunula, eponychium, hyponychium, nail ned, nail matrix
nail body
plate, visible portion of nail
free edge
nail body that extends pass digit
nail root
nail buried under skin
lunula
proximal crescent shaped end
eponychium
cuticle, epidermis that adheres to nail wall
hyponychium
secures nail to fingertip (distal end)
nail bed
below nail plate, no stratum granulosum
nail matrix
proximal to nail root, contains dividing cells
functions of nails
protect digits, support and counterpressure, grasp objects
Thick skin locations
palms, digits, soles
thickness of thick skin
0.6-4.5mm
layers of thick skin
5 layers- lkucidum present, thicker strata spinosum and corneum
C, L, G, S,B (greatest friction occurs)
what does and doesn’t thick skin have?
ridges are present, no hair, no oil glands, many sweat glands, denser sensory receptors
location of thin skin
all other parts that don’t have thick skin
thickness of thin skin
0.1mm-0.15mm-epidermal thickness
layers of thin skin
4 layers- strtum lucidum lacking, thinner strata spinosum and corneum
what does and doesn’t thin skin have?
no ridges-due to less developed and fewer dermal papillae), has hair, has oil glands, few sweat glands, sparse sensory receptors
how does the integumentary system help with thermoregulation?
hot- sweating, dilating blood vessels near surface–>more blood flow
cold-sweat decreases, blood vessels constrict, less blood flow- conserve heat. skeleton muscles contract to produce heat (shivering)
why is the skin a blood reservoir?
8-10% bv of dermis
how does the integumentary system help with protection of the body?
lipids retard water, regulates evaporation, keeps skin/hairs from drying out, recognize and kill bacteria
cutaneous sensation
tickle, vibration, pressure, temp, pain
excretion and absorption
excretes sweat and absorbs topical medications etc.
how does the skin synthesize vitamin D?
precursor molecules activated by UV rays–>enzyme in liver and kidneys use UV to make Calcitriol (active form of vitamin D)
