The Integumentary The Integumentary SystemSystem
Review of membranesReview of membranes
Types of membranes1.serous
◦ line body cavities that do not open to the outside
visceral – covers the organ parietal – covers the cavity
◦ made up of epithelium and loose connective tissue
◦ secrete serous fluid for lubrication
Serous membraneSerous membrane
Types of membranesTypes of membranes
2. mucous ◦ line cavities with openings to the
outside oral and nasal cavities openings of digestive, reproductive,
respiratory, and urinary systems
◦ made up of epithelium on loose connective tissue
◦ contain goblet cells to secrete mucus
mucous membranes of mucous membranes of stomachstomach
Types of membranesTypes of membranes
3. synovial ◦ line joint cavities◦ consist only of connective tissues◦ secrete lubricating synovial fluid
4. cutaneous membrane - skin
Synovial membraneSynovial membrane
Cutaneous membraneCutaneous membrane
The Integumentary The Integumentary SystemSystemintegumentary = coveringcomposed of skin, sweat and oil
glands, hair, nailsmini-excretory system
◦ removes urea, salts, water through sweatlarge organcomposed of 3 distinct layers
◦ epidermis◦ dermis◦ hypodermis
Functions of Functions of Integumentary SystemIntegumentary System1. protection from abrasion, uv
radiation, keeps out bacteria/viruses and prevents water loss
2. sensation of heat, cold, touch, pressure, pain
3. vitamin D production4. temperature regulation5. excretion of wastes
EpidermisEpidermisoutermost layercomposed mostly of keratinized
stratified squamous epitheliumavascularcomposed of 4-5 layersgrow new epidermis every 25-45
days
layers of epidermislayers of epidermis
1. stratum basale – layer of reproducing cells at base of epidermis
◦cuboidal or columnar cells◦nourished by blood vessels of dermis◦millions of cells produced daily◦push older cells to surface where
they become keratinized resist abrasion, produce permeability
barrier
layers of epidermislayers of epidermis
2. stratum spinosum3. stratum granulosum4. stratum corneum
◦ most superficial◦ dead, squamous cells filled with keratin◦ 25 or more layers thick◦ areas subjected friction form calluses
* stratum lucidum (palms and soles)
skin colorskin colormelanocytes: cells in stratum
basale◦produce melanin
yellow to brown to black protects cells from uv radiation freckles and moles – melanin
concentrated in one spot Racial differences determined by amount,
kind and distribution of melanin.
skin colorskin colorcyanosis (bluish colored skin)
◦caused by low oxygen in bloodredness
◦blushing, fever, hypertension, inflammation, allergy
pallor◦fear, anger, anemia, low blood
pressure, impaired blood flow
skin colorskin colorjaundice
◦liver disorders, excessive bilebruises
◦blood clotted in tissue spaces (hemotoma)
◦unusual bruises: low vitamin C, hemophilia
albinism◦recessive genetic trait◦deficiency of melanin◦fair skin, white hair, unpigmented irises
DermisDermismade mostly of
connective tissue◦ collagen, elastic
fibers Collagen is directional;
causes stress lines.
binds epidermis to underlying tissue
vascular, carry nutrients to upper layers and regulate temperature
DermisDermis2 layersdermal papillae
◦ nerve fibers, sensory fibers (Meissner corpuscles), hair follicles
Dermal Papillae are projections from the dermal layer into the epidermal layer.◦ help to deliver oxygen/nutrients from the
vascular system to the epidermal layer
dermal papillae dermal papillae
Meissner corpusclesMeissner corpuscles
DermisDermisreticular layer
◦ deepest skin layer◦ blood vessels, sweat and oil glands, deep
pressure receptors (Pacinian corpuscles)
HypodermisHypodermissubcutaneous layerloose connective and adipose tissuesnot part of the skin; base layer it
rests uponattaches skin to underlying organscontains blood vessels that supply
the skinno real boundary between dermis
and subcutaneous layersstores fat for padding and insulation
Accessory organs of the Accessory organs of the skin skin 1. Hair extension of epidermis deep into
dermis found over most of human body
◦ mostly useless produced in hair bulb which rests on
dermal papillae columns of keratinized epithelial cells
◦ continues to grow as new cells are added at the root
HairHair
Parts of the hairshaft – above
surface of skin◦ Medulla – soft center◦ Cortex - hard◦ Cuticle – outer
covering single layer of
overlapping cells that holds hair in follicle
root – part of hair in follicle
hair follicle – below surface of skin
hairhairhair bulb – base of follicle where hair grows cell division – living cells
push up and become keratinized
arrector pili – small bands of smooth muscle
connect each side of hair follicle to dermal layer
contraction – goose bumps
arrector piliarrector pili
hair colorhair colorgenetic traitmelanin in hair bulbfades with ageno melanin = white hair
Accessory structuresAccessory structures2. Nails thin plate; keratinized stratum corneum cellsparts of nail◦ free edge◦ nail body (part that is seen)◦ nail root – covered by skin◦ nail matrix – gives rise to cells that form nail
lunula – whitish crescent at base of nail
◦ nail bed – place of attachment◦ cuticle – stratum corneum on nail body
Accessory organs of Accessory organs of skinskin3. Sebaceous glandssimple, branched grape-like glandconnected by duct to superficial part of
folliclenot on palms or solesproduce sebum – oily, lipid-rich
◦ lubricates hair and surface of skin◦ waterproofs and moisturizes◦ kills bacteria◦ whiteheads/blackheads – blocked glands◦ acne – infected glands
Accessory organs of Accessory organs of skinskin4. Sweat glands – two typesmerocrine
◦ simple, coiled gland ◦ located in all areas of skin◦ most numerous in palms, soles◦ respond to body temperature◦ secrete water and some salts◦ open to surface of skin via sweat pores◦ Sweat on skin cools body.
Accessory organs of Accessory organs of skinskinapocrine
◦ simple, coiled, tubular gland◦ Secretions are thick and organic.
broken down by bacteria to produce body odor
◦ open into hair follicles of axillary and genital areas◦ become active at puberty
modified sweat glands◦ ceruminous – produce earwax◦ mammary – produce milk