Chapter 6, sections 6.2-6.5

accessory structures

originated from the epidermis, extend into dermis or hypodermis

accessory structures of the skin

hair follicles, nails, skin glands

what happens in accessory structures remain intact

injured/burned dermis can regenerate

nail plate (body)

visible portion, keratinized cells, overlies nail bed

nail bed

surface of skin,under nail plate

nail matrix

active growth region, not visible at proximal end of nail bed

lunula

pale,half-moon-shaped region over nail matrix; nail matrix conceals deeper blood vessels

cuticle

fold at proximal end of nail; part of stratum corneum that extends slightly over nail

hair papilla

contains blood vessels to nourish hair

arrector pili muscle

attached to hair follicle, contracts in response to cold or fear, and causes goosebumps

androgenic alopecia

most common types of blandness, pattern baldness, top of head loses hair

hormones associated with androgenic alopecia

low level of testosterone (men) or estrogen (woman)

cells in bald spots

progenitor cells are lacking, stem cells present

alopecia areata

body produces antibodies that attack hair follicles

sebaceous glands

usually associated with hair follicles, absent on palms and soles

what kind of glands are sebaceous glands

holocrine

what do sebaceous glands produce

sebum

sebum

keeps hair and skin soft and waterproof

what does sebum contain

fatty material and cellular debris

excess sebum

results in acne

acne vulgaris

a disorder of sebaceous glands

why is acne common at puberty

sebaceous glands are excessively responsive to androgens

what do sebaceous glands clog with to produce acne

extra sebum and epithelial cells

why can clogged glands create infection and inflammation

anaerobic bacteria

what is acne best treated with

vitamin A, systemic antibiotics, salicylic acid, benzoyl peroxide

sweat (sudoriferous) glands

widespread in skin

where to sweat glands originate

in deeper dermis or hypodermis as ball-shaped coils

3 types of sweat glands

eccrine (merocrine), apocrine, specialized

accrine (merocrine) glands

respond to elevated body temp, open to body surface through pores

apocrine sweat glands

open to hair follicles, respond to emotions and pain

how do apocrine sweat glands secrete

exocytosis

where are apocrine sweat glands found

axillary and groin areas

specialized sweat glands

ceruminous glands and mammary glands

ceruminous glands

ear wax

what is set point monitored by

hypothalamus

deep body temp

37 celsius or 98.6 fahrenheit

what is heat produced by

most active cells (liver, skeletal and cardiac muscle)

convection

heat loss from skin into circulating air currents

how does the body communicate rising temp

thermoreceptors signal hypothalamus

dermal vessel in high temp

vasodilation

deep blood vessel in high temp

vasoconstriction

dermal blood vessels in low temp

vasoconstriction

deep blood vessels in low temp

vasodilation

hyperthermia

abnormally high body temperature; skin dries, weakness, dizzy,nauseous, headache,rapid pulse

hypothermia

low body temp; confusion,lethargy,loss of reflexes and consciousness

inflammation

body’s attempt to restrict spread of infection, blood vessels in affected tissues dilate and become more permeable, allowing fluids to leak into the damaged tissues

shallow cut (affects only epidermis)

results in epidermal cells along its margin to divide more to fill gap

deep cut ( reaching dermis or subcutaneous layer)

results in blood vessels breaking, released blood forms a clot

consistence of blood clots

fibrin, blood cells, platelets

scab

formed from clot and dried tissue

fibroblast contribution to cuts

secrete collagen fibers to bind wound together

phagocytic cells in cut

remove dead cells and debris, scan sloughs off

scar

elevated mass formed by excess collagenous fibers

superficial, partial thickness (first degree) burn

injures only epidermis, as in suburn; redness heat, inflammation

healing of first degree burn

days to weeks, no scarring

deep, partial-thickness (second degree) burn

destroys epidermis and some dermis, as in burn from hot liquid

skin reaction to second degree burn

may blister, healing varies

healing of second degree burn

stem cells in hair follicles and glands can help regenerate skin, usually recovers completely with no scarring

full-thickness (third degree) burn

destroyed epidermis,dermis, accessory structures

healing of third degree burns

some healing from margins, often required skin graft, skin substitutes

rule of nines

divides body into multiples of nines, used to estimate extend of injured body surface from a burn for treatment

use of rule of nines estimate

plans to replace fluids, electrolytes, and skin can be figured