Intugmentary Sytem- HAP

integumentary system

Consists of the skin, mucous membranes, hair, and nail

function of the integumentary system

provide a barrier, protect deep tissue, water retention & thermoregulation, excretion, houses cutaneous receptors, synthesizes vitamin d

largest organ

skin (7% of body weight)

subcutaneous membrane

hypodermis

what is skin made up of

dermis and epidermis

what is the epidermis

stratified squamous epithelium

how does thick skin differ from thin skin

thick skin has 5 layers, thin skin has 4, thick also has thicker stratum corneum and stratum lucidum

how are superficial layers created

basal cells are metabolically active and undergo mitosis

what is special about surface cells

are flattened and are keratinized (full of keratin)

what are the four types of cells in the epidermis

keratinocytes, melanocytes, tactile epithelial cells, dendritic cells

what do keratinocytes do

produce keratin

what is a keratin

a tough fiborous protein (an intermediate fiber(cytoskeleton))

What do melanocytes produce?

melanin

what does melanin do

makes dark skin pigment to help protect from UV light

how is melanin transferred

from melanocyte to keratinocyte

what is a tactile epithelial cell

merkel cell

what is the function of a tactile epithelial cell

a receptor for tough and is associated with sensory nerve endings

what is a dendritic cell

immune cell system

what is the function of a dendritic cell

patrol the epidermies for foreign entities and engulf them

what is the deeper region of the skin

dermis

what are the two layers of the dermis

papillary layer and reticular layer

what type of tissue is the dermis

vascular connective tissue

what is in the dermis

flibroblasts, macrophages, mast cells, white blood cells, various proteins

what plexuses are in the dermal blood vessels

dermal & subpapillary

what is the function of the plexuses in the dermis

provide blood and regulate temperature

where is the papillary layer

deep to the startum basale of epidermis

what makes the papillary layer unique

the fingerlike projections of dermis into the epidermis

where is the reticular layer located

deep to the papillary layer

what makes the reticular layer unique

thick layer of dense irregular connective tissue

what is unique about the hypodermis

it is NOT part of the skin

what is the hypodermis

subcutaneous tissue

what is the hypodermis made up of

areolar and adipose connective tissue

what does the hypodermis do

anchors skin to underlying structures

What are skin appendages?

derived from the epidermis but all extend into the dermis

what are nails

a modification of the epidermis

what are nails made of

hard keratin

how is a nail plate formed

from dividing cells that are proximal to the nail fold known as the nail matrix

what is contained in the nail plate

nail plate, nail folds, free edge, body, root

how does hair develop

from invaginations of the epidermis forming the follicle

what does hair contain

shaft and hair root

what is the shaft of hair

dead kertainized cells that project out of the skin's surface

what is the hair root

embedded in the dermis surrounded by hair follicle

what are the two types of cutaneous glands

sebaceous glands and sudoriferous

what does sebaceous glands produce

sebum

what are sebaceous gland connect to

hair follicles

what does sebum do

flows superficially to cover skin makes hair and skin oily for protection

what is sweat

mostly water with some salts

what are the two types of sudoriferous glands

eccrine and apocrine

what are eccrine glands

produce true sweat and are connected to surface via pores

what are apocrine glands

produce a special sweat containing fats & proteins connected to hair follicles in the axillary and genital areas

three basic layers of skin

epidermis, dermis, hypodermis

three main cell types of the epidermis

keratinocytes: produces the fibrous intermediate filament protein keratin

melanocytes: secrete pigment

dendritic cells

immune surveillance, present antigens to immune system

five layers of the epidermis

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

stratum corneum

outermost layer of the epidermis, which consists of flattened, keratinized cells

stratum lucidum

clear layer, thick skin only

stratum granulosum

one helps form keratin, the other contains the glyolopids

stratum spinosum

desmosomes, dendritic cells and melanin

stratum basale

the deepest layer of the epidermis consisting of keratinocyte, melanocytes

Eumelanin

brownish black pigment

Phaeomelanin

red and yellow

Carotene

yellow-orange pigment

Haemoglobin

reddish hue

description, function and location of connective tissue areolar (dermis)

description: three fibres

function: wraps and cushions organs

location: mumcous membrane, epithelia, organs

description, function and location of connective tissue, dense irregular

description: fibroblast

function: structural strength

location: organs, joints, digestive tract

2 layers of dermis

1. papillary 20%

2. reticular 80%

dermal ridges

fingerprints, sweat glands

cleavage lines

collagen fibres, heal rapidly, dense irregular tissue

flexure lines

dermis folds, near joint

eccrine sweat glands (cutaneous)

temp control, merocrine (exocytosis)

apocrine sweat glands (cutaneous)

sexual scent glands, merocrine

sebaceous glands

water loss, lubricate skin and hair, sebum

eccrine sweat glands

coiled tubular gland, secrete true sweat

apocrine sweat glands

larger deeper, fatty, proteins

mammary glands

produce milk

three coats of hair

lanugo, vellus, terminal hair

Hair structure

medulla, cortex, cuticle

Cycle of hair growth

anagen, catagen, telogen, early anagen

subcutaneous tissue (hypodermis)

apidose tissue, adipocyte, triglycerides, anchors