test 2 bio 201 asu (integumentary, bone tissue, joints.)

what is included in the integumentary system?

skin (aka dermis or cutaneous membrane), epidermis, dermis, hypodermis, hair and nails, and cutaneous glands

whats the largest organ in the body?

skin

what are the two layers of the skin? (and the secret third that isnt technically a part of it)

epidermis (stratified squamous epithelium) and dermis (deeper layer of connective tissue) and hypodermis

whats the thickness of normal, thin and thick skin?

normal= 1-2 mm

thin= .mm (in places like eyelids)

thick= up to 6mm (in places like palms and soles)

thick skin has no hair or sebaceous glands

facts about the epidermis

no blood vessels, superficial to the dermis (closest to surface), surface is dead cells and keratin, very few nerve endings, 5 zones/layers (takes 30-40 days to migrate from the deepest zone to the surface)

what are the layers of the epidermis, deepest to most superficial?

-stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum

facts about stratum basale

-deepest layer

-single layer of cuboidal or low columnar cells sitting on basement membrane

-receives nutrients from connective tissue below

-4 types of cell

stratum spinosum

-2nd deepest layer

-thickest layer

-contains more living keratinocytes

-contains cells that alert the immune system to foreign invaders (dendritic cells)

stratum granulosum

-3-5 layers of granule and vesicle containing keratinocytes

-cells are dying

-release lipids from vesicles

-form a protein-lipid epidermal water barrier (makes skin waterproof and prevents dehydration)

stratum lucidum

thin, translucent zone

thick skin only

no nuclei or organelles

cells are flled with eleidin (product in keratin production)

dermis

-thickness= .2-4mm

-contains blood vessels

-has accessory structures such as hair follicles, sebaceous glands, sweat glands, nail roots and nerve endings

-dermal papillae are upward extensions of the dermis that form fingerprints

-smooth muscle= piloerector muscles

-skeletal muscle in face= expressions

what are the two layers of the dermis and what is their function?

papillary layer (loosely organized areolar tissue and allows for motility of white blood cells) and reticular layer (deepest 4/5, dense irregular connective tissue, thicken collagen that makes stretch marks, adipocytes)

hypodermis

-aka subcutaneous tissue or superficial fossa

-binds skin to underlying tissue

-more adipose than dermis

-functions: energy reservoir, thermal insulation

-8% thicker in women

-hypodermic injections

what are the different things that make up skin color?

hemoglobin (red pigment visible through dermal collagen fibers), carotene (yellow pigment from diet that concentrates in stratum corneum and subcutaneous fat), and melanin (produced by melanocytes which are hereditary)

what does melanin do?

-synthesize UV radiation from sunlight

-produce yellow, brown, black, and reddish hues

-concentrated in freckles and moles

genetic lack of melanin

albinism

bruise (visible blood clotted)

hematoma

blueness in skin- O2 deficiency in circulating blood (cold weather)

cyanosis

redness due to dilated cutaneous vessels

erythema (sunburn, anger, embarrassment)

yellowing of the skin and sclera

jaundice (due to excess bilirubin in blood, liver disease)

golden brown in the skin

addison disease (deficiency of glucocorticoid hormone)

different kinds of birthmarks

hemangiomas (skin discolored by benign tumors of dermal blood capillaries), strawberry birthmarks (disappear in childhood), port wine birthmarks (last for life)

flat aggregations of melanocytes

freckles

elevated melanized skin

moles, sometimes with hair, usually benign

what do friction ridges create/do

leave oily fingerprints on touched surfaces, unique pattern formed during development

where are flexion creases and flexion lines

flexion creases: form after birth by repeated closing of the hand

flexion lines form in the wrist and elbow areas

what are the functions of the skin?

barrier, vitamin D synthesis, cutaneous absorption, sensory functions (heat, cold, touch, pressure, vibration, pain), thermoregulation, psychological and social functions

nails

clear and hard

derived from stratum corneum (densely packed w/ keratin)\

-spoon shaped can indicate iron deficiency

-clubbing can indicate hypoxemia

growth rate is 1mm a week

hair aka pilus

filament of keratinized cells

stratum corneum of the skin is composed of pliable soft keratin

hair and nails have hard keratin

hairs found everywhere but thick skin