chapter 5-integumentary system Flashcards
integument
-“covering” ~16% of body mass
-composed of cutaneous membrane, epidermis(superficial epithelium), dermis(underlying C.T w/blood supply) & accessory structures
functions of integument system
- protect underlying tissue from infection, exposure & dehydration
- excrete salts, water & organic wastes
- maintain normal temp. (conserve & radiate heat)
- synthesize vitamin D3 for calcium metabolism
- store nutrients (fat)
- sensory detection: touch, pressure, pain & temp.
what layer of the epidermis are stem cells located?
stratum basale
in the stratum granulosum layer, the keratinocytes are full of keratin fibers,
lamellated granules and what other granules?
keratohyaline
epidermal ridges
pattern of fingerprints created by the undulations
vitamin A is supplied to your epithelium from what yellow-orange pigment from plant material in your diet?
carotene
what is the function of melanin in keratinocytes?
protectin of the DNA from UV damage
an albino person fails to produce what?
melanin
cells of the lower layers of the epidermis use UV energy and cholesterol to produce what vitamin?
D3
the papillary layer is composed of what type of tissue?
areolar connective
lamellated corpuscles/pacinian corpuscles
the pressure and vibration receptors located in the reticular layer of the dermis
hair, nails, cutaneous glands, and epidermis are all composed of what type of tissue?
epithelial
the fat, rounded end of a hair follicle that contains the papilla and matrix is the what?
hair bulb
what is the shiny surface layer of hair?
cuticle
what is the hair matrix?
stem cells that divide to make hair
what is the function of the root hair plexus?
detect hair movement
contraction of the what muscle pulls the hair follicle perpendicular to the skin?
arrector pili
what do sebaceous glands produce?
sebum
where does sensible perspiration come from?
merocrine/eccrine sudoriferous glands
where on the body are the ceruminous glands?
external ear canal
apocrine sudoriferous glands are active when in your life?
after puberty
true or false: the growth cycle of both hair and nails is the same?
false: hair is cyclic with a resting phase of no growth, nails are continous
following injury to the dermis, what cells begin secreting collagen?
fibroblasts
following an injury to the cutaneous membrane, mesenchymal cells are important to replace what?
connective tissue cells
keloid
a visible scar following repair of the skin
why is a patient with second and third-degree burns more prone to dehydration?
loss of keratinized epidermis results in increased insensible perspiration
why are the elderly more prone to overheating in hot weather?
reduced function of eccrine sudoriferous glands results in less evaporative cooling
epidermis(superficial integument/ superficial cutaneous membrane)
-stratified squamous epithelium
-avascular
-mostly keratinocytes
-two type: thick & thin skin
kertainocytes
cells filled with soft keratin protein
thick skin
-up to 0.5mm, 5 layers, no hair
-palms of hands & soles of feet
thin skin
-0.1mm or less, 4 layers, usually hairy
-most of body
stratum basale (layer of the epidermis
-single layer attached to basal lamina by hemidesmosomes
-extends into the dermis as an epidermal ridge
-cells mostly basal /germinative cells(stem cells) that constantly divide
-some melanocytes & tactile discs/merkel cells in hairless skin (touch receptors)
stratum spinosum (layer of the epidermis)
-8-10 layers of keratinocytes attached by desmosomes
-some cells can divide
-some epidermal dendritic cells/ langerhans cells present (immune response)
stratum granulosum (layer of the epidermis)
-3-5 layer of keratinocytes producing keratin fibers
-contain keratohyaline & lamellated granules
-no cell division
-nuclei & organelles begin to disintegrate
stratum lucidum (layer of epidermis)
-thick skin only
-flat packed keratin filled kerationocytes
stratum corneum (layer of epidermis)
15-30 layers of dead keratinocytes that have been keratinized(cornified)
keratinized (cornified)
-soft keratin fibers glued parallel arrays by keratohyaline & extracellular space filled with glycolipids from lamellated granules
-water & chemical resistant
fingerprints
function to enhance gripping
callus
thickening of the epidermis due to repeat friction
blister
separation of epidermal layers or epidermis from dermis, space fills with interstitial fluid
pigment based
epidermal pigments & blood pigments contribute to skin color
carotene (epidermal pigmentation)
-yellow-orange from diet
-converted into vitamin A
-localized to epithelium
-functions in normal maintenance of epithelia & photoreceptors
-excess accumulates in stratum corneum
melanin (epidermal pigmentation)
-brown from melanocytes
-for UV protection
melanocytes
-in stratum basale
-synthesize melanin from tyrosine (amino acid)
-packed in melanosomes
-transferred to the cytoplasm of keratinocytes
-cluster around the topside of the nucleus
-eventually digested by lysosomes
pale people
small melanosomes present only in stratum basale & spinosum
dark people
larger, greater # of melanosomes, retained up through stratum granulosum
freckle
overproduction of melanin from a single melanocyte
UV exposure
-some needed for vitamin D3 production
-excess = damage(DNA mutations)
-fibroblasts -> altered C.T. structure (wrinkles)
epidermal cells (excess of UV exposure)
melanocytes -> cancers: squamous cell carcinoma melanoma
dermal circulation
hemoglobin pigment
oxygenated blood
red color, hemoglobin in RBCs, through skin looks pink
vasodilation of oxygenated blood
skin looks more red
vasoconstriction of oxygenated blood
skin looks more pale
cyanosis
low oxygen, blood deep purple, skin appears blue/purple resulting from low temp. heart failure & asthma
jaundice
liver fails to excrete bile, accumulates in the skin turning it yellow
Addisons disease
pituitary gland secretes excess adrenocorticotropic hormone, stimulates melanocytes resulting in excess melanin, bronzing
albinism
genetic mutation in melanin biosynthesis pathway. lack of pigmentation in skin, hair & eyes
vitiligo
autoimmune disease -> destruction of melanocytes
vitamin D3 production
-cells of stratum spinosum and basal UV energy + cholesterol = vitamin D3
-vitamin D3 used by the kidney to synthesize the hormone calcitriol
-calcitriol necessary to signal small intestine to absorb calcium
-no vitD -> no calcitriol -> no calcium absorption -> weak bones
dermis (deep integument/ deep cutenous membrane
-contains: all cells of C.T> proper, accessory organs of integument(hair follicles, sweat & sebaceous glands), blood vessels, lymphatic vessels, nerves, sensory receptors
-two layers: papillary & reticular layers
papillary layer (layer of the dermis)
thin (20%) areolar connective tissue, comprise dermal papillae, function to feed epidermis
reticular layer (layer of the dermis)
thick (80%), dense irregular connective tissue, elastic & collagen, function to provide strength & flexibility
wrinkles
dermis stretched beyond in elastic capacity, collagen fibers damaged
stretch marks
-collagen & elastic fibers torn
-cells parallel to lines of cleavage will has faster & with less scar than those perpendicular
lines of cleavage
collagen & elastic fibers arranged in parallel bundles aligned to resist excepted direction of force
contusion
bruise, trauma that ruptures blood vessels but doesn’t break skin, blood pools in dermis and must be removed by phagocytes (slow process)
tactile/merkel cells
deep layer of epidermis, superficial touch
free nerve endings
superficial dermis, pain & temperature
tactile/meissner’s corpuscles
superficial dermis, light touch
lamellated/pacinian corpuscles
deep dermis, pressure & vibration
subcutaneous layer (hypodermis)
-areolar & adipose C.T.
-tightly interwoven with the reticular layer of the dermis
-not part of the cutaneous membrane
-stabilizes the position of skin while permitting independent movement of skin & muscles
-no vital organs: safe for SubQ injection, vascular for quick absorption
subcutaneous layers during children, puberty, male & femaes
children: even layer of adipose
puberty: adipose shifts
male: neck, arms, abdomen, lower back
female: breasts, butt, hips, thigh
what are the 4 accessory structures of integument
- hair follicles & hair
- sebaceous & sweat glands
- nails
*all of these structures are anchored in the dermis but are derived from epidermal tissue
hair
-human body: ~ 2.5 million, 75% on body
-everywhere except palms, soles, lips & certain genitalia
-hair itself is dead but derived from live epidermal tissue
hair follicle
-tube of stratified squamous epithelium anchored in dermis; surrounds, supports & produces hair
-two layers: internal & external sheath
internal root sheath (layer of hair follicle)
contacts hair
external root sheath (layer of hair follicle)
contacts glassy membrane
glassy membrane
thick basal lamina between epithelial follicle & connective tissue dermis
hair bulb
expanded base of follicle where cell division occurs surrounds papilla & matrix
hair papilla
connective tissue at base of bulb, contains capillaries and nerves & support matrix
hair matrix
dividing epithelial cells and melanocytes above papilla that form new hair
hair root
embedded in dermis, not yet fully formed; contains live cells
hair shaft
-pokes through the epidermis; fully organized dead hair
-has 3 layers: cuticle, cortex, medulla
cuticle (layer of hair shaft)
outermost, overlapping dead keratinized cells from shiny surface
cortex (layer of hair shaft)
middle layer, dead cells contain hard keratin to provide stiffness
medulla (layer of hair shaft)
core, dead cells contain soft keratin and air to provide flexibility
flattened shaft (determines feel of hair shaft)
kinky hair
oval shaft (determines feel of hair shaft)
silky & wavy hair
round shaft (determines feel of hair shaft)
straight & often stiff hair
vellus hairs (type of hair produced)
-“peach fuzz”
-lacks medulla
-covers body, at puberty hormone can trigger switch to terminal hairs
terminal hairs (type of hair produced)
-thick, coarse, pigmented
-all three-layers
hair color
-range from yellow to black due to melanin & melanocytes in hair matrix
-red: iron added
-melanin stored in the medulla & cortex
-with age, melanin declines & air pockets in medulla increase = gray or white hair
hair growth
~0.33mm/day, not continuous: cycle of
growth and rest
active phase of hair growth
new hair added to hair root by dividing cells of hair matrix (weeks-years)
regressive phase of hair growth
cells of hair matrix stop
dividing, hair root and hair papilla separate loose hair = club hair
resting phase of hair growth
cells of hair matrix and hair
follicle remains inactive (1-3 months)
hair length differences
-difference in time
spent in active phase
-eyebrows = few months
-head = many years
history or exposure of a person through their hair
during hair growth nutrients and toxins incorporated into hair
alopecia
shift from terminal hair to vellus hair, thinning/balding, some degree expected with age
male pattern baldness
-genetic alopecia, early age onset
-treatments: aimed at converting vellus hairs
to terminal hairs
hair removal
-difficult to achieve a permanent result
-any remaining matrix cells can regenerate all hair follicle structures
hair functions
head: UV protection, cushion head from trauma & insulation
nostrils, ear canals, eyelashes: prevent entry of foreign materials
body hair: sensor detection
root hair plexus
sensory nerves at
the base of hair follicles that detect slight movement of hair
arrector pili muscle
-attached to every hair follicle
-contract to stand hair perpendicular to the skin
surface (goose bumps)
-smooth muscle: involuntary
sebaceous glands (exocrine)
-holocrine secretion
-secrete sebum into hair follicle
-functions: lubricate & protect, prevent evaporation & inhibit bacterial growth
-sebaceous glands active in the fetus, then off until puberty, on whole adult life
sebum
lipids+cholesterol+
proteins+electrolytes
acne
inflammation of a sebaceous gland, usually due to bacterial infection
merocrine/eccrine sudoriferous glands (sweat glands)
-2 to 5 million all over body
-produce sensible perspiration: 99% water
+ electrolytes + organic nutrients + antibodies + antimicrobial agents + organic wastes
-merocrine secretion
-small coiled tubular
glands
-located in superficial
dermis
-open directly on
surface of skin
-secrete in response
to high temp or
stress
functions of sensible perspiration
-evaporative cooling of the surface of the skin to reduce body temp & excrete waste electrolytes and drugs
-protection: prevent adherence of microbes
(antibodies), physically wash off microbes & antimicrobial agents to kill microbes
dermicidin (antibiotic)
apocrine sudoriferous/sweat glands
-merocrine secretion
-armpits, nipples, groin
-secrete into hair follicles
-secretion is sticky and cloudy: sensible perspiration +proteins+lipids
-microbes eat it -> wastes = body odor
-glands deep in dermis
-surrounded by myoepithelial cells: contract in response to the sympathetic nervous system stimulation
-active only after puberty
mammary glands (special apocrine sweat glands)
-located in female breasts
-secrete milk during lactation
ceruminous glands (special apocrine sweat glands)
-located in external ear canal
-secrete cerumen (earwax)
integumentary gland control
-merocrine sudoriferous glands can be turned on and off in localized regions in response to temperature or emotions
-sebaceous and apocrine sudoriferous glands are either all on (body-wide) or all off, with no local control
nails
-scale-like projections on the dorsal surface of distal digits
-functions: protect tips from mechanical stress, assist gripping
-consists of dead cells containing hard keratin
-new nail formed at nail root
-nail growth is continuous
injury & repair
-integument can function independently of nervous and endocrine systems to maintain own homeostasis
-mesenchymal cells of dermis can regenerate connective tissue
-germinative cells (basal cells) of epidermis can regenerate epithelial tissue
keloid
thick area of scar tissue covered by smooth epidermis
integumentary injury repair step 1
- injury occurs -> damage & bleeding
-mast cells trigger inflammatory response
integumentary injury repair step 2
-blood clot forms & dries into a scab
-phagocytic cells remove debris
-stratum basale cells divide & migrate around wound
-fibroblasts & mesenchymal cells divide & migrate into dermal area of wound
-fibroblasts secrete collagen fill gap
-endothelial cells repair & grow new capillaries
-granulation tissue is formed= blood clot +fibroblasts secreting collagen+capillaries
integumentary injury repair step 3
-new epidermal cells migrate over granulation tissue
-epidermis reforms under the scab
integumentary injury repair step 4
-when epidermis is completely scabbed and shed
-fibroblast continue to secrete collagen forming a scar
-mesenchymal cells differentiate to replace C.T. cells
-hair follicles, glands, muscles & nerves not usually regenerated: replaced with collagen
first degree burn
damage to the surface of
epidermis, heals on own
second degree burn
damage to epidermis
and superficial dermis, heals on its own
third degree burn
-damage to whole
cutaneous layer (epidermis, dermis, accessory structures), granulation tissue cannot form thus no healing
-requires skin grafts or “living bandages”
burns > 20% over body
-can kill
-affects: fluid & electrolyte balance, thermoregulation & protection from pathogens
age-related changes 1-4
- stem cell activity declines: skin thin, repair difficult
- epidermal dendritic cells decrease: reduced
immune response - vitamin D3 production declines: calcium absorption declines -> brittle bones
- Glandular activity declines: skin dry, body can overheat
age-related changes 5-8
- Blood supply to dermis declines: tend to feel cold
- Hair follicles die or produce thinner hair (terminal vellus)
- Dermis thins and becomes less elastic: wrinkles
- Sex characteristics fade: fat deposits spread out, hair patterns change
