integumentary+endocrine systems Flashcards
epidermis
outer layer that continually replenishes, resists friction, and waterproofs
made out of stratified squamous cells
dermis
VASCULARIZED dense lower layer of interlacing collagen and elastic fibers embedded in a semi fluid matrix
provides skin tone and toughness
cells: fibroblasts, macrophages, mast cells, wbc
also contains nerve fibers and lymphatic vessels
hypodermis
not really part of the skin
considered subcutaneous tissue
superficial fascia- superficial to tough ct wrapping/fascia of skeletal muscles
funct: most of bodies fat storage, thermoreg, insulation, and protection from bones compression
gained weight comes from fat placed at the hypodermis
tissue type of the epidermis
stratified squamous cells
layers of the epidermis
stratum basale stratum spinosum stratum granulosum stratum corneum if thick: stratum lucidum
stratum basale
1 row of columnar/cuboidal stem cells attached to the dermis
intense mitotic activity/regeneration
contains many melanocytes 10-25%
keratinocytes arise from here
melanocytes
spider like cells abundant in the stratum basale and loc bt keratinocytes
deposit melanin granules to shade the top side of the nucleus to protect DNA from UV
keratinocytes
produce keratin a fibrous protein that water proofs and toughens skin
is most abundant and renews every 25-45 days
stratum spinosum
prickly layer sev layers thick pre keratin filaments and melanin granules is attached by desmosomes contains langerhans cells
langerhans cells
dendritic cells
come from bone marrow and migrate to epidermis
phagocytes that ingest foreign substances and help activate the immune system
stratum granulosum
3-5 layers of keratinocytes
keratinization
cells start to flatten and accumulate keratohyalin granules and lamellated granules
here organelles start to break down, cells begin to flatten and die
keratohyalin granules
protein that organizes keratin into thicker bundles to toughen and form keratin in the upper layers
lamellated granules
glycolipids are forced out of the extracellular space- a major factor in slowing water loss across the epidermis
stratum corneum
horny layer
20-30 cells thick
flattened non nucleated keratinized cells whose cytoplasm is filled w keratin
protects the skin from abrasion and penetration
glycolipid bt cells waterproofs this layer
unsuitable for microorganism growth
stratum lucidum
thick skin only
2-3 rows of clear, flat, dead keratinocytes just above the stratum granulosum
thick skin
only in palms and soldes
thicker more protective stratum corneum
extra layer- stratum lucidum
thin skin
found everywhere but palms and soles
merkel cells of epi
arise from epidermis and conduct to the dermis
intimately associated with a disk like sensory nerve ending
functions as a sensory receptor for touch
nerve ending is NOT an accessory organ of the skin its part of the ns
papillary layer of dermis
20%
loose areolar CT
highly vascularized and innervated
has dermal papillae that invade the epidermis and dermal pegs/downward projections
these friction ridges used in finger prints
sensory receptors of the papillary layer
free nerve endings-pain,tickling, itch, hot, cold
meissners corpuscles-light touch and pressure
reticular layer of dermis
80%
lower dense irregular CT w collagen and elastin
cutaneous plexus-innervation of skin by at least 2 spinal nerves
tension lines- pattern of collagen fibers that heal quickly; lose elastic w age so skin sags
flexure lines-deep dermal folds at joints for mvmt
sensory receptors of the reticular layer
ruffinins corpuscles
pacinian corpusucles
glycolipids
mortar bt cells of corneum to reduce water loss
keratin
tough fibrous protein for protection
hair
dead keratinized cells w melanins for color
loc all over body except palms, soles, lips, nips, and parts of external genitalia
alerts body to pres of insects on skin
guards scalp from physical trauma, heat loss, and sun
matrix-actively dividing area of bulb that makes hair
root bulb plexus-wrapped in sensory nerves
arrector pili
bundle of smooth muscle that lifts hair to make goosebumps to trap heat in cold or fear
nails
scale like modification of epidermis
hard keratin at superficial layers
nail bed for growth
eccrine glands
merocrine sweat gland
most numerous
loc on palms, soles, forehead for thermoreg
sweat secreted thru pores
apocrine glands
loc at goin/pits
mature at puberty
secrete reg sweat+ fats/proteins into a hair follicle
produce odor bc bac on skin decomposes fats/proteins
ceruminous glands
modified apocrine glands
in lining of external ear canal
make ear wax
deters insects, and blocks entry of other materials
mammary glands
specialized sweat glands that secrete milk
sweat is
99% h20, salt, urea, uric acid, antibodies, and microbe killing peptides (dermicidin)
acidic to help immune syst and protect skin
comp depends on health/diet
secreted thru pores
sebaceous/oil glands
all over the body except palms and soles
produce sebum-oily secretion from holocrine glands
dumps into hair follicle when stimulated by hormones
softens/lubes hair and skin
prevents brittle hair
slows h2o loss
helps kill bac
skin functions overview
protection thermoreg cutaneous sensation excretion metabolism blood res
protection: chemical barriers
acid mantle- sweat w low ph retards multiplication
defensins-nat antibiotics that punch holes in bac
cathelicidins- protective peptides that prevent strep A infection
melanin-pigment shields
protection: physical/mechanical barriers
continuity of skin
hard keratinized stratum corneum
glycolipids- block h20 loss/diffusion and sol substances
protection: biological barriers
dendritic langerhans cells of immune syst
macrophages of dermis_2nd line
DNA absorbing sun and releasing it as heat
body temperature regulation
evaporation of sweat releases heat
vasoconstriction- conserves heat
vasodialation-releases heat
cutaneous sensation
meissners corp-aware of caress+clothing (light touch)
tactile disc
pacinian corp- bumps/contact w deep pressure
hair follicle recep-hair mvmts
free nerve endings- pain, chem, heat, cold
excretion
elimination of nitrogen containing wastes thru sweat
metabolism
- modified cholesterol converted to cholecalciferol, a vit D precursor then converted to vit D for calc absorp
- keratinocytes enzymes can disarm many cancer causing chemicals that penetrate epidermis
- activation of steroid hormones cortisone-hydrocortisone (anti inflam)
blood reservoir
extensive dermal vascular supply 5% of bodies entire blood volume
when muscles need more blood, the NS redirects blood supply to them
burn
tissue damage inflicted by intense heat, electricity, radiation, or certain chemicals that denature proteins in skin cells and destroy protection against microbes and thermoregulation
first degree
only epidermis is damaged skin funct remain intact redness, swelling, pain heals in 3-6 days ex-sunburn
second degree
injures epidermis and papillary dermis (upper layer)
some skin functions are lost
blisters
skin regen in 4-6 wks if infection prevented
ex-grease, steam, flame
superficial-very painful/moist 7-21
deep-doesnt heal as well, lots of scar, treated like 3rd, req surgery/grafting, over 21 days
third degree
injures epidermis, dermis, and assoc structures skin function is lost, nerve damage-no pain slow regen req surgery/grafting
fourth degree
most severe
reaches beyond subcutaneous tissue and into muscles, nerves, and bones
no pain, may be black/charred
ex-chemicals
serious burns are life threatening because
- lg water loss, plasma/plasma proteins might induce shock
- bacterial infection
- no thermoregulation
- reduced circulation, decreased urine, diminished immune resp
facial burns-worry of suffocation
burns at joins-limit mobility
extent of a burn is determined by
rule of 9’s
burn is considered critical if
25% body in 2nd deg burns
10% body in 3rd deg burns
or 3rd deg burns of face, hands, feet
basal cell carcinoma
78% most common
loc in stratum basale-rarely metastasizes to dermis/hypodermis
least malignant
squamous cell carcinoma
20%
arises from keratinocytes of stratum spinosum
grows rapidly and metastasizes if not removed
melanoma
5% least common but most malignant cancer of melanocytes highly metastatic and resistant to chemo req surgery and immunotherapy 30% of all melanomas begin in a mole key to survival-early detection
cancer
abnormal growth of cells which tend to proliferate in an uncontrolled way and in some cases metastasize
lose specified job
signs to be aware of ABCDE
asymmetry border color diameter elevation
endocrine system consists of
ductless glands, isolated and clustered cells of the gut, and specialized nerve endings that secrete hormones
neurons communication is limited to other neurons, muscles, and glands but the endocrine system is able to regulate any cell in the body to allow the following
maintaining homeostasis of blood and volume
controlling reproductive activities
regulating development, growth, metabolism
controlling digestive processes
endocrine gland
any of the various ductless glands such as the thyroid, adrenal, or pituitary having hormonal secretions that pass directly into the blood stream
hormone
blood borne substances/chemicals produced in endocrine glands that are involved in regulating a variety of processes
regulate metabolic function of other cells
lag times from seconds to hours
prolonged effects
chemical classification of hormones
steroids
amino acid based
steroids
fat soluble/synth from cholesterol
cross thru cell membrane
receptor located inside of the cell
binds to DNA_DNA transcription_MRNA_new proteins
amino acid based
regulate cellular activities from cell surface bc it cant penetrate the plasma memb
receptor loc in the cell memb
G-protein activation
causes cell to produce intracellular messengers like CAMP (2nd messenger)
stimulates enzyme activity which produces a desired effect
effects alter plasma memb perm stim protein synth activate/deactivate enzyme synth induce secretory activity stim mitosis
stimulation of hormones synthesis and release can be done by
HORMONAL- release of hormone by another hormone
HUMORAL-hormone release due to blood changes
NERVOUS SYST-can turn on/off factors that affect endocrine syst
why do hormones circulate to all tissues but only activate cells referred to as target cells
because target cells must have specific receptors to which the hormone binds to (either inside of the cell or on the plasma membrane)
what is the master gland
the hypothalamus
bc it is in charge of the pituitary gland
anterior pituitary gland
adenohypophysis
made up of glandular tissue
hypohphyseal portal system- no neural connection to the hypothalamus
VASCULAR CONNECTION
PRODUCES hormones
regulates the release of hormones by other endocrine glands
posterior pituitary gland
neurohypophysis
down growth of hypothalamic neural tissue and infundibulum
direct neural connection w hypothalamus
for STORAGE of hormones
heart
produces atrial natriuretic peptide ANP
targets the kidney
decreases the amount of sodium ions in the blood, lost in the urine,
reduces blood pressure and volume
gastrointestinal tract
enteroendocrine cells that release local acting digestive hormones to regulate a wide variety of digestive functions
placenta
temporary endocrine gland
releases estrogen and progesterone that sustains the pregnancy
kidneys
secrete erythropoietin which signals the production of RBC
skin
produces cholecalciferol the precursor of vit D
bone
osteocalcin
improves glucose handling by increasing the production of insulin and reduces body fat
