integumentary system

anatomy

the integumentary system is composed of the

skin and its accessories

the integumentary system is one of the ____ ____ of the body

largest organs

what does the integumentary system all do? (5)

protective covering, homeostasis, prevents water loss, makes biochemicals, excretes waste

the skin has __ distinct layers

2

epidermis-

composed of stratified squamous

dermis- thicker; has connective tissues, ….

elastic and collagenous fibers, smooth muscle, nervous tissue and blood

a _____ ______ separates the two layers

basement membrane

subcutaneous layer (hypodermis) has looose

the subcutaneous layer is mostly made up of

adipose

is the subcutaneous a true layer of skin?

no

the subcutaneous layer has no sharp ____ between ___

boundary; dermis

the subcutaneous layers contains blood vessels that supply

skin and adipose tissue

in the epidermis, the stratified squamous lacks

blood vessels

what is the deepest layer of the epidermis

stratum basale

the stratum basale is close to ___ and provides blood flow

dermis

deeper cells divide, pushing older cells towards ___ causing them to ____

surface; die

keratinization-

old cells die

keratin protein fills

cytoplasm

when keratin protein fills cytoplasm, it makes cells

tough, fiberous, and waterproof

many layers of the keratin cells form the

stratum corneum

the 4 distinguishable layers in the in the epidermis

stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale

way to remember 4 layers

c’mon lets get some biscuits

___ _____ tends to be balanced with ___ ____

cell production; cell death

areas where skin cells divide faster than they die due to pressure cause

calluses

epidermis functions prevents: (4)

excessive water loss, mechanical injury, harmful effects from chemicals, and pathogens from entering

melanocytes produce

melanin granules

melanin absorbs

UV radiation from sun

when melanin absorbs UV radiation, it prevents

mutations in DNA

melanocytes lie in ___ portion of epidermis

deepest

cytocrine secretion

transfer of melanin into other cells

skin color is due largely to

melanin

most people have the same amount of

melanocytes

skin color is also affected by ____ and _____

environment; physiology

KNOW HOW TO EXPLAIN HOW THE SKIN RENEWS ITSELF

.

boundary between the epidermis and dermis is uneven due to ___ ___ and ___ ____

epidermis ridges; dermal papilae

conical projections of the dermis are found

all over the body

conical projections are most abundant in

feet and hands

undulations cause

fingerprints

genetics determine

pattern

how can babies change their fingerprint pattern?

when they press against the uterus

the dermis layer is composed of what tissue

connective

what gives skin its elasticity and toughness

collagenous and elastic fibers in a gel-like ground substance

dermal blood vessels supply _____ to all skin cells

nutrients

____ _____ (axons) are scattered throughout

neuron processes

motor processes carry impulses to ____ and _____

muscles and glands

sensory processes carry impulses

away from receptors

what are the accessory structures in the dermis

nails, hair follicles, sebaceous glands, sweat glands

nail plate-

hard part

nail bed- specialized epithelium continuous with

epithelium of skin

lunula-

thick, whitish semi-circle on ends of nails

what is the fastest growing part of the nail

lunula

how does the lunula form? epithelium divides…

new cells become keratinized

keratin scales push

nail plate over nail bed

a group of cells in a tub like depression is called a

follicle

follicle extends from

surface into dermis

what layer contains the hair root

dermis

epidermal cells at base are nourished by

dermal blood vessels

____ determine hair color

genes

direct type and amount of pigment are produced by

melanocytes

black/brown hair is called

eumelanin

blonde/reddish hair is called

pheomelanin

grey hair is called

pigmented and unpigmented

muscles attached to hair-

arrector pili

arrector pili is attached to each hair follicle and they

contract when cold

sebaceous gland- groups of

specialized epithelial cells

sebaceous glands are associated with

hair follicles

sebaceous glands secrete oily mixture of

fatty material and cellular debris

sebum-

keeps hair soft, pliable, waterproof

sweat glands- composed of a small

tube that starts as a small ball-shaped coil

sweat glands are located in deeper-

dermis or superficial subcutaneous