Ch5 Flashcards
Integument
bodys largest organ. covers entire body surface (skin)
2 layers of the itegument
epidermis and dermis
epidermis
a layer of the integument. consists of stratified squamous epithelium
dermis
a layer of the epithelium. consists dense irregular and areolar connective tissue
subcutaneous layer or hypodermis
(NOT PART OF INTEGUMENTARY SYSTEM, BUT CLOSELY INVOLVED) a layer deep to the dermin. composed of areolar and adipose connective tissue.
where does the integument meet mucous membranes
nostrils, lips, anus, urethral and vaginal opening. transition and seamless and epithelial defenses remain intact
what are the functions of the integument (7)
protection, provention of water loss/gain, temp regulation, metabolic regulation, immune defense, sensory reception, secretion
how dose integument protect
physcal barrier from injury, chemicals, and light. selectively permeable bc it does still absorb some things
selective permeability
some materails can pass thru
how does integument prevent water loss/gain
epidermis is water resistant so water only exits thru sweat glands.
does succumb to transdermal water loss
transdermal water loss
fluids slowly escape through epidermis to surface where they evaporate
two types of transdermal water loss and definition
insensisble perspiration- release of water vapor from sweat glands even when not sweating
sensible perspiration- visible sweating
what happens when water vapor is release during insensible perspiration
it mixes w sebum and creates a thin acidic film on skin to prevent more water loss and bacterial invasion
how does integument regulate temp (both hot and cold)
vast capillary and sweat glands in the dermis.
blood vessels dilate to dissapate heat if too hot and sweat glands release fluid onto school too cool down through evaporation.
blood vessels constrict when too cold and send blood to deeper body tissues
how does the integument regulate metabolism
when exposed to uv radiation the skin produces cholecalciferol through its epidermal cells which is then coverted to calcitriol which allows us to increase the amount of calcium we absorb from food. this overall helps regulate calcium and phosphate in the blood
what is cholecalciferol and when is it produced
vitamin d3 and produced by epidermal cells when exposed to uv radiation.
what is calcitriol, where is it produced, and and what is it synthesized from
the active form of vitamin d3 and is a hormone. increases absorption of calcium and phosphate from the intestines into the blood, helping us absorb more from our food.
synthesized for cholecalciferol by endocrine cells in kidneys.
how does the integument create immune defense
initiates an immune response in epidermis with epidermal dendritic cells when pathogens penetrate the epidermis. also against epidermal cancer cells
epidermal dendritic cells
play a role in phagocytizing pathogens that have penetrated the epidermis
how does the itegument play a role in sensory reception
sensory neurons in the skin
tactile cells
large specialized epithelial cells that stimulate specfic nerve endings when distorted by fine touch or pressure
what does the integument secrete
sweat
epidermis
the epithelium of the integument. a keratinized stratified squamous epithelium.
layers of the epidermous from deep to superficial
stratum basale, stratum spinosum, stratum granulosum, stratum lucum(in thick skin only), and stratum corneum
which epidermal strata are composed of living keratinocytes and what are the rest made of
basale, spinosum, and granulosum; dead keratinocytes
what cells occupy the stratum basale
keratinocytes, melanocyte, tactile cells
keratinocytes
most abundant cells in epidermis and occur in all strata. get their name from keratin. make epidermous almost waterproof
keratin
in epidermous of skin. fibrous structural proteins that are tough and insoluble. twist around each other to form filaments of they cytoskeleton.
what are keratins found in epidermal cells of skin called
cytokeratins
melanocytes
have long, branching cytoplasmic processes and are scattered among keratinocytes of the stratum basale. produce and store melanin in response to UV expose
how do melanocytes shield DNA from ultraviolet radiation
they produce melanin and transfer pigment granules (melanosomes) by phagocytosis or exocytosis into keratiocytes within the basal layer. the pigment accumulates around the nucleus of cels and shields the DNA
stratum granulosum (granular layer)
consists of 3 to 5 layers of keratinoccytes superficial to stratum spinosum
what two types of granules are in the stratum granulosum
keratohyalin granules (involved in keratinization process)
lamellar granules (fuse with plasma membrane and extrued their lipids into the extracelular space
keratinization
keratinocytes fill up with keratin.
as cells pass thru the granulosum and keratin fillaments begin to develop, cells become thinner and flatter. membanes thicken and are less permeable. nucleus and organelles disintigrate and cells die. the material left within the cell is used to form a layer of keratin fibers sandwhiched between phospholipid membranes. not complete until reaches more superficial layers of epidermis. all fully keratinized cells are dead but strong bc they contain keratin.
stratum lucidum (clear layer)
only in thick skin like palms. cells are pale and featureless and have indistinct boundaries. keratinocytes in this layer are flattened and filled with eledin
eledin
intermediate product in process of keratin maturation
stratum corneum (hornlike layer)
most superficial layer. you see it when u look at skin. 20-30 layers of corneocytes.
corneocytes
dead scally keratinized cells in stratum corneum. anucleate and tightly packed together
anucleate
no nucleus
how long are keratinocytes present after their formation
1 month. 2 weeks to migrate to the corneum, 2 weeks remaining there until falling off
hemoglobin
oxygen vinding protein in red blood cells. exhibits bright red color when binding to oxygen giving blood vessel the red color
melanin and the two types
pigment in melanocyte
eumelanin and pheomelanin
why is some skin darker than other
all ppl have same amt of melanocytes but the activity and color varies causeing different skin tones
carotene
yellow-orange pigment from eating some veggies. converted into vitamin a and accumulates in keratinocytes of the startum corneum
nevus
a mole. overgrowth of melanin forming cells, harmells but can become malignant with too much UV
freckles
localized areas of excessive melanocyte activity
hemangeoma
skinn discoloration due to cells proliferating and forming a benign tumor
capillary hemangioma
bright red to yellow nodules that usualyl dissaper during childhood
carniverous hemangiomas
port wine stains. larger dermal blood vessels that may last a life time
friction ridges
increase friction so that objects do not slip easily from hands or feet. formed from large folds and valleys in dermis and epidermis
dermatoglyphics
the study of friction ridge patterns
components dermis and what kind of connective tissue does it consist of
deep to the epidermis and ranges in thickness from 0.5-3.0 mm.
areolar and dense irregular connective tissue, these conn tiss layers composed of collagen and firbroblasts.
blood vessels, nails, sweat glands, sebaceous glands, hair follicles, nail roots, sensory nerve ending, and smooth muscle tissue.
two major regions of dermis
superficial papillary layer and deeper reticular layer
papillary layer of dermis
superficial region adjacent to epidermis.
composed of aereolar connective tissue
dermal papillae, function, and what do they contain
projections of dermis toward epidermis. interlock with epidermal ridges to increase area of contact between epidermis and dermis, as well as connect them.
contain capillaries to supplie nutrients to epidermis cells. house sensory receptors.
epidermal ridges
deep projections of the epidermis that connect with dermal papillae.
reticular layer of dermis, function
deeper larger portion of dermis extending from papillary layer on top to subcutaneous layer.
consists of dense irregular connective tissue that projects bundles of collagen fibers in all direction.
what dose the work reticular refer to in the reticular layer of dermis
“network” of mesh of collagen fibers that surround structures of the dermis like hair follicles, sebaceous glands, sweat glands, nerves, blood vessels
lines of cleavage
the direction/orientation of collagen fibers bundles. their function is to resist stress as they are a result of the direction of applied stress in routine movement
what happens when you cut lines of cleavage at different angles in a surgical context
cutting with the lin of cleavage will usually remain closed, cutting against them will have cut remain open and have slow healing/scarring.
what types of fibers contribute to the physical characteristics of the skin
elastic (allow stretch and recoil) and collagen fibers (impact tensile strength)
striae, what causes them
stretch marks. when skin stretched beyond capacity it tears the collagen fibers and causes these.
what factors can diminish the flexibility and thickness of the dermis, and what does this cause
UV light and aging
sagging and wrinkly skin
innervation
to supply w nerves
what are the functions of nerve fibers
monitor sensory receptors in dermis and epiderm
control blood flow and gland secretion rates
what supplies the epidermis cells and the dermis with nutrients
blood vessles in the the dermis.
largest lays within border btwn reticular layer of dermis and subcutaneous layer, smaller brand out into hair follicles, sweat glands, etc.
how does the dermis drain
smallest arterial vessels connect to cappilary loops within dermal papillae, then drain into small vessels forming a vessel network that merges into small veins, draining the dermis
how does dermis regulate temp
vasoconstriction and vasodilation of blood vessels.
subcutaneous layer / what is it made of
(hypodermis or superficial facias) deep to the integument but not considered part of it.
areolar connective tissue and adipose connective tissue.
subcutaneous fat
when adipose connective tissue predominates this is what the subcutaneous layer is called
what does the subcutaneous layer do for the body
pads and protects
enery reservoir
thermal insulation
how is subcutaneous layer related to reticular layer
conn tiss fibers of retic layer are woves with subcut layer to stabilize position of skin and bind it to tissues
what layer are drugs injected to
subcutaneous bc it has a large vascular network for rapid absorption
what is dif in subcutaneous layer between men and women
thicker in femails, thinner in males.
fat distribution in men is in neck, upper arms, abs, lower back, buttock.
fat dist in women is breast, buttocks, hips, thighs
epidermal dervatives
derived from eipthelium of epidermis. hair, nails, exocrine glands.
what are nail and hair composed of that is different from glands
dead cells(kertinocytes). glands composed of living epithelial cells
