Please enable JavaScript.
Coggle requires JavaScript to display documents.
chapter 5 skin and integumentary system (5-7 (sebaceous gland (associated…
chapter 5 skin and integumentary system
5-1
epidermis
stratum granulosum
is composed of 3-5 layers of flattened granular cells
stratum spinosum
is composed of many layers of spiky cells with large nuclei
stratum lucidum
translucent layer cells separating the corneum and granulosum
stratum basale
( germinativum) = innermost layer directly above the basement membrane
stratum corneum
outermost layer, composed of dead epithelial cells filled with the protein keratin
main function is protection
pigment =melanin
determines the skin color and is produced by melanocytes in stratum basale
5-2
skin color
environmental factors
chemicals
drugs ( antihistamines and antiiotics)
UV rays
Physiogic factors
hemoglobin in dermal blood vessels=pink
lack of hemoglobin in dermal blood vessels=blue
carotene may accumulate in s. corneum =orange
inability to breakdown hemoglobin =yellow
Genetic factors = people of different races have essentially the same number of melanocytes, but the amount of melanin produced varies
5-3
vitamin d3 ( sunlight converts a cholesterol related steroid)
adds in adsortion of calcium
liver converts it into calcitrol
weak and flexible bones without it
skin cancers that are most common
sqaumous cell carcinomas
more superficial layers
malignant melanoma
dangerous usually begins as a mole
metastasize thru the lymphoid system
basal cell caricinoma
b. originates in stratum germinativum
a. most common form of skin cancer
prevention= avoid mid day sun and were sun block
5-4
describe the structure of the dermis
A. dermis - inner layer of the skin, and binds the epidermis to underlying tissues
has 2 distinct layers
papillary layer
surface forms dermal papillae ( finger-like projections into the epidermis) that form fingerprints in thick skin
Meissners corpuscles( sensory receptor for light touch)
composed of loose areolar CT
reticular layer
bundles of collagen fibers
elastic fibers
reticular fibers which give skin its strength and resiliency
pacinian sorpuscles - sensory receptors for deep pressure
5-5
hypodermis
subcutaneous layer ( hypodermis) = beneath the skin
function=insultation
structure = adipose tissue and blood vessels
5-6
hair follicles
hair root
or base in the deep dermis , follicle throughout dermis
hair shaft
cuticle
outer layer shingle layer
cortex
middle layer, flexible soft keratin
medulia
inner layer, hard keratin
5-7
sebaceous gland
associated with every hair follicle
secretion (holocrine)=sebum (oil)
holocrine gland (simple cuboidal epithelium)
sebrum is secreted into hair follicle
disorders
seborrhea ( hyperduction of sebum; oily scales)
acne( hypersecretion of sebum ; ducts clog and inflame)
merocrine glands
characteristics
respond to elavated temp. excercise no odor in secretion
function throughout life
no associated with hair follicles
secretion
salts and wastes
structure
duct in dermis
pore at surface
coil in deep dermis
5-8
nails
structure
nail root
cuticle fold of the stratum corneum
nail body covers the nail bed
functions
protection of digit ends
manipulation
epithelium undergoing keratinizations
5-9
regulation of body temp is 98.6
heat production is mostly a by-product of cellular metabolism
heat loss is controlled by regulating dermal blood flow
vasodilation - increases dermal blood flow which also increases heat loss
vasoconstriction - decreases derma blood flow which decreases heat loss
heat loss is by four methods
conduction- less heat loss
convection is heat loss surrounding air
radiation - the most heat loss in this mode
evaporation- heat loss varies
problems in temperature regulation
hyperthermia
elevated body temperature by humid air decreasing evaporation
hypothermia
low body temperatures and are very dangerous if core body temp drops below 94 degrees