A&P- Integumentary system

skin

largest organ of body and cutaneous membrane

functions of the integument.

protecction

prevents water loss

temp regulation

immune defense

excretion

2 layers are..

dermis and epidermis

epidermis

superficial layer

keratinized stratified squamous

avascular

5 layers

cells of epidermis

keratinocytes

melanocytes

langerhan cells

merkel cells

stratum basalw

deepest layer

single layer of cells

attached to dermis by basement membrane

contains melanocytes

produces melanin and protects from UV

stems cells constantly divide

youngest keratinocytes

stratum spinosum

layer (8-10) of numerous cells

cels divide less rapidly

contain keratinocytes

epidermal dendritic cells

immune cells fight infection

stratum granulosum

2-5 layers of flattened diamond-shaped cells

keratinization begins here

water-resistant glycolipid that slows down water loss

stratu lucidum

translucent layer found only on palm of hands, sole of feet

consists of dead keratinocytes

stratum corneum

most superficial layer

20-30 layers of dead squamous cells

structural strength and protection

prevents water loss

thick epidermis

palm of hands, sole of feet

has 5 epidermal strata

no hiar follicles or sebaceous glands

thin epidermis

covers most of the body

only 4 layers

dermis

lies deep to the epidermis

contains collagen fibers

contains blood vessels, sweat glands, oil glands, hair follicles, nail roots, sensory nerve endings, and muscle tissue

papillary layer of dermis

composed of areolar CT

dermal papillae project from the dermis and indent the epidermis

• has free nerve endings:

  • nociceptors (pain)

  • Merkel (tactile disc)

• friction ridges- enhance gripping

reticular layer of dermis

composed of dense irregular

makes up 80% of thickness in dermis

contains blood vessels, sweat glands, oil glands, hair follicles, nail roots, sensory nerve endings and muscle tissue

cleavage lines

flexure lines (palms)

stretch marks

hypodermis

not a layer of the integument

anchors integument to bone and muscle

consist of adipose and areolar CT

hair shaft

projects form the skins surface

columns of dead keratinized epithelial cells

inner medulla

present in thick hair only; includes soft keratin in the core, simialr to that in the epidermis

middle cortex

several layers of keratinocytes with heard keratin

outer cuticle

single layer of keratinocytes with hard keratin, wears over time producing ‘split ends’

hair root

enclosed by follicle

hair bulb

actively growing portion of the hair

dermal papilla

region with blood vessels and nerves that reach the hair bulb

piloerector muscle

cluster of smooth muscle fibers that connect the hair follicle to the upper region of the dermis produces goose bumps

vellus body

hair of children and adult females, usually light

terminal hair

usually darker, eyebrows, scalp

nails

made if hard keratin

parts of nail

free edge, body, root, nail folds, cuticle

glands

a structure that secretes substances into a duct, into a surface, or into blood

sudoriferous

sweat glands

lactiferous

milk glands

sebaceous

oil glands secrete sebum, oily waxy substance

ceruminous

locates only in external ear, form earwax

merocrine glands

most common

sweat exits through a sweat pore in epidermis

sensitive to temperature

produce normal body perspiration

apocrin glands

secrete water

produced at puberty

produce body odor

ducts open into hair follicles

oil glands

everywhere besides palms and soles

simple branched acinar rounded glands

connected to hair follicle

melanin

pigment

blood

hemoglobin

carotene

thickness of the stratum corneum

albinism

inherited inability ot produce melanin

vitiligo

condition in which there is a partial or complete loss of melanocytes from patches of skin

cyanosis

low oxygen concentration, blue

jaundice

excess bile pigment in the blood, liver- yello

pallor

decrease in blood floe to dermis- white

erythema

increased blood flow to derm- red

rashes and hive

allergy to foods and drugs

wounds

common skin pathology defined as any disruption in the skin’s integrity

lacerations

cut or tear in the skin, typically repaired with sutures or stitches

burn rule of nines

body is divided into 11 areas

each area accounts for 9% of total body surface

area surrounding the genitals accounts for 1% of the body’s surface area

the amount of fluid lost in adults can be estimated by computing the percentage of body surface burned

cancer

one the of the msot common disease in teh world; cause by DNA mutation

basal cell carcinoma

most common

arises from keratinocytes in the stratum basale of the epidermis

Skin regularly exposed to UV radiation is at risk for developing these tumors

appears as a nodule with a central crater

rarely metastasizes to other tissues

can be resolved by surgical removal

squamous cell carcinoma

second most common

cancer of keratinocytes of stratum spinosum

scaly plaques may ulcerate and bleed

tumors are more likely to metastasize than basal cell carcinoma

malignant melanoma

cancer of melanocytes

early detection of melanoma is critical due to tendency to metastaize

arms of cancerous melanocytes extend down into dermis and access dermal blood vessels

treated with surgical removal, radiation, and chemo

prognosis depends on size of tumor, depth, and if it got to other tissues

A

asymmetrical shape

B

border irregularity

C

color- black and blue

Diameter

generally larger than 6 mm

E

evolving- changing shape and size

tissue repair

process of wound healing, occurs differently in different tissues and is dependent on the tissues ability to regenerate

aging

wrinkling

decrease in skin’s immune responsiveness

dehydration and cracking

decreased sweat production