Flashcards in Chapter 5 Deck (65):
skin (cutaneous membrane) is important for what?
superficial layer that consists of keratinized stratified squamous epithelium resting on a basement membrane dead cells and avascular (no blood vessels so no constant supply of oxygen); die a lot b/c avascular
contains : keratinocytes (cells that make keratonin)
deep to epidermis and basement membrane; consists of loose connective tissue and dense irregular connective tissue
what are some examples of acessory glands in the skin?
skin contains ____ and ______ that are responsible for goosebumps
sensory receptors and arrector pili muscles
because the epidermis is avascular, how does it get oxygen and nutrients?
Must rely on diffusion of oxygen and nutrients from blood vessels in deeper dermis
what are the superficial cells made up of? why?
About 50% of cells in epidermis are too far from adequate blood supply to sustain life; superficial layers are made up entirely of dead cells
also known as superficial fascia or subcutaneous fat, is deep to dermis
what does the hypodermis do?
-abundant blood supply
-anchors skin to muscle and bones
What're the 5 functions of the integumentary system?
4. Excretion (of nitrogen containing wastes)
5. vitamin D synthesis
process that enables nervous system to perceive changes in the body’s internal or external surroundings; critical to homeostasis: we need to recognize when we get in dangerous temperatures; sufficient ability to feel pain
process where waste products and toxins are eliminated from body; this helps maintains an electrolyte balance (don't want too much or too little)
Why do we need Vitamin D?
Vitamin D is required for calcium ion absorption from small intestine; calcium ion is critical for nerve function, muscle contraction, building and maintaining bone tissue, and many other physiological functions
what two things make the epidermis stronger?
1. desmosomes- link the epidermis together
2. manufacture of keratonin (which is a tough fiborous protein)- makes the epidermis less subject to mechanical stress
Describe the stratum basale layer.
-closest cells to blood supply in dermis; therefore most metabolically and mitotically active cells in epidermis
-in vitamin D synthesis and replacement of dead keratinocytes
-cells in this layer are alive and dividing
describe the stratum spinosm
-sits on top of stratum basale so still close to blood supply
-also metabolically and mitotically active cells= alive
describe the stratum granulosum
-filled with keratin bundles or a lipid-based substance;
-both secreted by exocytosis
-cells slowly begin to die in this layer
describe the stratum lucidum
-narrow layer of clear, dead keratinocytes;
-found only in thick skin extra protective layer
describe the stratum corneum
– outermost layer of epidermis; consists of several layers of dead flattened keratinocytes with thickened plasma membranes; filled mostly with keratin bundles and little else
As keratinocytes in deeper strata divide, how do they get cells into superficial layers?
push cells above them into more superficial layers
How and where are keratinocytes replaced?
how: replaced by mitosis of cells
where: stratum basale and spinosum where blood supply is available for such activities
location and functions of epidermis subjects it to both physical and environmental stress; stratum corneum is continuously shedding dead cells that must be replaced to maintain integrity of epidermis; starts in basale then sheds in the corneum
keratonin life cycle
located in stratum spinosum; phagocytes of immune system; protect skin and deeper tissues from pathogens defense against invaders of deeper regions
in stratum basale; sensory (touch) receptors associated with small neurons in dermis:
stratum basale; produce melanin; protein skin pigment ranging from orange-red to brown-black
what's the diff between thick and thin skin?
Thick skin: has all five epidermal layers and a very thick stratum corneum; does not have hair follicles but contains many sweat glands
thin: stratum lucidum is missing; only 4 layers
highly vascular layer deep to epidermis
what is the function of the dermis? (3)
1. Provides blood supply for epidermis
2. Contains sensory receptors
3. Anchors epidermis in place
-thinner most superficial of two layers of dermis;
-Special collagen fibers are found in this layer at dermis-epidermal junction;
-extends into epidermal basement membrane to anchor epidermis to dermis
reticular layer. What's found in this layer?
-deep thicker layer that separates dermis from hypodermis
-Collagen bundles strengthen dermis and prevent traumatic injuries from damaging deeper tissues
-Elastic fibers allow dermis to return to its original shape and size after stretching
Found: Blood vessels, sweat glands, hairs, sebaceous glands, and adipose tissue are found in reticular layer
in dermal papillae; sensory receptors that respond to light touch stimuli; protects us
sensory receptors that respond mainly to changes in pressure and vibration associated with skin
small visible lines in epidermis created by interaction between dermis and epidermis; sweat pores help create these; best seen in hands and feet
found in areas where dermal papillae are more prominent due to presence of thick collagen bundles
what is responsible for skin markings associated with tension or lines; cleavage lines and flexure lines
Gaps found between collagen bundles in dermis create indentations in epidermis; particular pattern you find in the region of neck and trunk; circular in nature
why should we follow tension lines?
On your arm your tension lines go up and down, so when u get a cut, if the cut also goes up and down it will lay closer together and heal faster
how do we determine skin color? where are these contained?
amount of melanin
contained in melanocytes in strato basale
function of melanin?
reduce synthesis of vitamin D
why do ppl in Africa have darker skin than ppl in the USA?
Individuals living in regions exposed to high amounts of UV radiation (such as Africa) may have developed darker skin to prevent excess vitamin D production
skin color depends on what?
Skin color depends on number of melanocytes found in a particular body region;
yellow-orange pigment found in food items such as egg yolks and orange vegetables (carrots, peaches, etc.)
found in red blood cells; transports oxygen throughout body; oxygen binds to the iron in this in an oxidation reaction; same reaction that causes iron to rust
Hemoglobin’s effect on skin color is an indirect result of what?; color of blood in where is visible through epidermis
what: blood flow in dermis
where: deeper dermis
small filamentous structures that protrude from surface of skin over entire body except in regions with thick skin, lips, and parts of external genitalia
what are some appendages of the integumentary system?
Accessory structures or appendages of integument include hair, nails, and glands
this is too sparse in humans to play a significant role in thermoregulation, temp regulation in animals tho; protects us from uv, external substances getting in our bodies
thin, nonpigmented hair found covering nearly entire body of a fetus; generally fall out around birth; replaced with one of two hair types
thick, coarse, and pigmented hair; found surrounding eyes and on scalp; used for protection; replaces other type of hair after puberty
thin, nonpigmented; sparse and light; found in remaining regions of body
Hair color is largely determined by _____ produced in matrix by melanocytes; what type of hair has the most of this?
black hair= lot of melanin; blonde= not so much
when aging, we don't make as much melanin which is why our hair turns gray
form of chemical communication in apocrine gland
most prevalent sweat gland; no association with hair; sweat, contains mostly water, waste products, and electrolytes; exits through sweat pores onto epidermal surface
eccrine sweat glands
sweat glad found in axillae, anal area, areola; produces body odor; influenced by sex hormones; pharamones
sweat gland that releases cerumen into hair follicles in ear (ear wax); traps and lubricates incoming particles
sweat gland that produces modified sweat product: milk
this gland is branched with clusters of acini surrounded by small ducts; converge to form a central duct that empties into hair follicle or small pore; makes and secretes sebum
sebum production increases after puberty
where can you find the sebaceous gland?
everywhere besides palms and soles of feet
waxy, oily mixture of mostly lipids; released by holocrine secretion; secretory cells accumulate sebum until cell ruptures; first line of defense against bacteria
wound caused by agents such as heat, extreme cold, electricity, chemicals, and radiation; grouped into three classes according to extent and depth of tissue damage: difficult to manage b/c of dehydration and infection
burn with Minor wounds that only damage epidermis;
Skin may develop erythema (red appearance) and some mild pain without any permanent damage
first degree burns
burn that Involves epidermis and part or all of dermis; Can result in pain, blistering, and scarring;
burn that's the Most damaging wounds; Involve epidermis, dermis, hypodermis; potentially even deeper tissue, like muscle or bone; Not generally painful at first because nerves are destroyed too
third degree burn
what is the rule of nines and how does it work?
-method to estimate how much of the body is affected by the burn