matinence of relativley stable internal conditions despite environmental changes

maintained by contributions from all organs

monitors environment

responds to stimulus

signals control center via afferent pathways

determines set point where variable is maintained

recieves receptor input

determines response

sends response signal to effector via efferent pathway

gets output from control center

responds with negative or positive feedback

receptors: temp sensitive cells in skin send message to brain via afferent pathways

control ceneter: thermoregulatory center in brain- signals via efferent pathway

effectors: recieve message and get sweat glands to work

response enhances stimulus ( more for infrequent events)

ex-enhanced labor by oxytocin

group of cells similar in structure that perform a common or related function

(histology)

epithelial: provides cover: skin, lining, glands

connective: structure: bone, cartilage, fat, blood

muscle: allows movement: skeletal, cardiac, smooth

nervous: provides control: spinal cord, brain, nerves

organ systems: have all 4 types

thin double layered membrane, makes walls of the ventral body cavity and outer surface of organs

(AKA serous membrane)

ouside: parietal serosa

inner wall: visceral serosa

Polarity

specialized contacts

supported by connective tissue

avascular, but innervated

can regenerate

Apical Surface: (upper, free) exposed to exterior or cavity. usually microvilli

Basal Surface (Lower) attached to noncellular

covering and lining epithelial tissue fit close together to form continuous sheets.

Bind adjacent cells (tight junctions and desmosomes) bind cells at many points- help maintain epithelial polarity.

all epithelial sheets rest on connective tissue.

reticular lamina: (under basal lamina) network of collagen fibers.

basement membrane: basal lamina + reticular lamina

reinforces epithelial sheet, resists stretch and tear.

No blood vessels in epithelial tissue

Nourished by diffusion from underlying connective tissue.

Supplied by nerve fibers (sense hot/cold, pressure)

High regenerative capacity

Stimulated by loss of apical-basal/lateral contacts

lost cells replaced by cell division

Epithelial description

(2)

Numer of layers:

simple: single layer

stratified: 2 or more layer

shape:

squamous: flat

cuboidal: cube shaped

columnar: tall and narrow

protect

absorb

filtrate

excretion

secretion

sensory reception

acts as selective filter-chooses what molecules can and cant enter epithelium

scaffold where cells migrate to repair wound

1 layer of epithelial tissue but appears as many

cells and nuclei at varying heights

lining of hollow urinary organs-stretches

(allows bladder to fill-6 layers to 3)

one or more cells that make and secrete a product.

secretion=water + protein

1.where product is released

2.endocrine: in, exocrine: out

3.relative cell #: uni/multi-cellular

4.structure: simple, branched, tubular, aveolar

integrated into epithelial linings of gastrointestinal and respiratory tracts

produce and secrete mucin: glycoproten component in mucus

provides structure and support for organ systems, insulation, energy, and water storage.

most abundant and widely distributed of primary tissues

connective tissue proper

cartilage

bone

blood

varied degrees of vascularity

composed primarily of extracellular matrix

loose connective proper (bone) highly vascularized

dense connective proper- poorly vascularized because fibers are close together.

ground substance: fluid, cell adhesion, proteins, proteoglycans, trap and store water.

fibers: collagen, elastic, retucular

cells: 'blasts, 'cytes, fat cells, mast cells, WBCs, macrophages

miotically active- secrete ground substance & fibers

fibroblasts: connective tissue proper

chondroblasts: in cartilage

osteoblasts: in bone

hematopoietic stem cells in bone marrow

Mature, less active form; maintain matrix

-chondrocytes: cartilage

-osteocytes: bones

-adipocytes: in fat

skin

keratinized stratified squamous epithelium (epidermis) attached to a thick layer of connective tissue (dermis)

line body cavities open to the exterior

bathed by secretions (mucous) or urine

epithelium lies over layer of loose areolar connective tissue, lamina propria

lines closed body cavities

two layers: parietal and visceral

simple squamous epithelium over thin areolar connective tissue

superficial region

stratified squamous epithelial tissue.

deep to epidermis

loose and dense connective tissue proper

deep to dermis

not part of skin, mostly apidose

most superficial layer; 20-30 layers of dead cells, essentially flat membranous sacs filled with keratin.

glycolipids in extracellular space.

typically 5 layers of flattened cells, organelles deteriorating

cytoplasm full of lamellar granules (glycolipids) and keratohyaline granules (keratin)

several layers of keratinocytes joined by desmosomes.

cells contain thick bundles of intermediate filaments made of pre-keratin.

appear spiny.

one row of activley miotic stem cells; newly formed cells become part of the more superficial layers.

melanocytes compose 10-25% of this layer.

produce the pigement, melanin-packaged into melanosomes, released and phagocytosed by keratinocytes

protects apical surface of keratinocyte nucleus from UV damage.

a type of macrophage

key activators of the immune system

sensory touch receptors

associated with a sensory disc (nerve ending) in the dermis

two layers of connective tissue

papillary: loose areolar

reticular: dense irregular

contains nerve fibers; blood and lymphatic vessels; hair follicles; oil and sweat glands

dead keratinized cells

everywhere except palms, soles, lips, nipples, and portions of genetalia

hair shaft has three layers:

medulla (middle)- cells with soft keratin and air spaces

cortex- many layers of flattened cells, contain pigment

cuticle-single layer, flat, scale like cells, hard keratin

-warm of insects on skin

-protect against physical trauma, heatloss, and sunlight

-guard eyes and nose from particles

expanded deep end

hair fillicle receptor:sensory nerve endings-touch receptors

hair matrix: activley dividing

smooth muscle attached to follicle

"goose bumps" and sebaceous gland secretion

-coarse, long hair of eyebrows, scalp

-at puberty

apears in axillary and public regions of both sexes

face and neck of males

deposited by meanocytes in hair bulb

-melanins (yellow, rust, brown, black); trichosiderin in red hair

-gray/white- decreased melanin production, increased air bubbles in shaft

alopecia:hair thinning, shedding outpaces growth (~40)

male pattern baldness: genetic, changes in follicle response to DHT result in shortened hair follicular cycles, vellus hair replaces terminal

scalelike modification of epidermis

protective cover for distal, dorsal surface of fingers and toes

-most numerous

-merocrine glands

-abundant on palms, soles, and forehead

-ducts connect to pores

function in thermoregulation

-sympathetic nervous system

secretion is sweat

99% water, salt, vitamin c, antibodies, waste

specialized sweat glands confined to axillary and anogenital areas.

sweat+fatty substance+proteins --> viscous, ordorless until bacterial interaction (body ordor)

ducts empty into hair follicles; begin functioning at puberty -acts as pheremone (unknown)

ceruminous gland- lining of external canal; secretes earwax

mammary gland- secretes milk

associated with & secrete into hair follicles

-arrector pili helps to move it out

secretes sebum

-oily holocrine secretion

-bactericidal; softens hair and skin

1.protection

2.body temp regulation

3.cutaneous sensation

4. metabolic functions

5.blood reservior

6.excretion

needed when barries are penetrated

cells divide + migrate

release of inflammatory chemicals

-signals to the rest of the body that there is damage.

-blood vessel dialation-> allows blood cells and platlets to go to damaged area

increase vessel permeability

clotting occurs

blood clot replaced with granulation tissue

epithelium begins regeneration

fibroblasts produce collagen fibers to bridge the gap

debris is phagocytized

scab detaches

fibrous tissue matures, epithelium thickens and begins to

reassemble adjacent tissue

results in fully regenerated epithelium with underlying scar tissue.

Burns: Partial Thickness

1st degree

epidermal damage only

localized redness, swelling (edema) and pain

Burns: Partial Thickness

2nd degree

epidermal and upper dermal damage

blisters appear

Burns: full thickness

3rd degree

entire thickness of skin involved

skin: white-gray, cherry red, or blackened

not painful-nerve damage

skin grafting usually needed

after 24 hours

infection

-debridement (removal) of burned skin

-antibiotics

-temorary covering

-skin grafts

-Basal cell carcinoma (bad)

-squamous cell carcinoma (worse)

-melanoma (worst)

most skin tumors do not metastasize (spread)

most skin tumors are benign (not cancerous)

over exposure to UV radiation

frequent skin irritation

genetics (melanomas)

least malignant; most common; on UV exposed aread of the face

stratum basale keratinocytes proliferate and slowly invade dermis and hypodermis

cured by surgical excision in 99% of cases

squamous cell carcinoma

2nd most common

involves keratinocytes of stratum spinosum

-scaly, reddened papule on scalp, ears, lower lip, and hands

-good prognosis if treated by radiation therapy or removed surgically

cancer of melanocytes

-occurs whereever melanocytes are found

-most dangerous, highly metastatic, resistent to chemotherapy

-treated by wide surgical excision with immunotherapy.

no blood vessels or nerves

perichondrium (dense connective tissue)

-all contains chondrocytes in lacunae and extracellular matrix

-provides support, flexibility and resistence

-Fine collagen fibers only

-most abundant type

-articular, costal, respiratory, nasal cartilage

-similar to hyaline cartilage, but contains elastic fibers (elastin) in addition to collagen

-external ear and epiglottis only

thick collagen fibers- has great tensile strength

-menisci of knee; vertebral discs

grow from the outside

cells secrete matrix against external face of existing cartilage

occurs during normal bone growth

calcified cartilage is not bone

206 bones

divided into two groups

long axis of body

skull, vertebral column, rib cage

bones of upper and lower limbs

gridles attacing limbs to axial skeleton

limbs longer than they are wide

limb, hand, foot bones

cube-shaped bones (wrist and ankle)

sesamoid bones (in tendons e.g. patella)

vary in size and number in different individuals

thin, flat, slightly curved

sternum, scapulae, ribs, most skull bones

complicated shapes

-vertebrae, coxal bones

support

protection

movement

mineral and growth factor storage

blood cell formation in red marrow cavities of certain bones

triglyceride (fat) storage in bone cavities

hormone prodction

lamellar

-sense bone; smooth and solid

(cencellous or trabecular)

-honeycomb of flat pieces of bone called trabeculae

-specifically arranged along lines of stress

-Solid

-tubular shaft forms long axis

-compact bone surrounding medullary cavity

epiphyses

-bone ends

-external (compact bone); internal (spongy bone)

-articular cartilage covers articular surfaces

-between epiphyseal line [remnant of childhood bone growth at epiphyseal plate]

white, double layered membrane

covers external surfaces except joint surfaces

outer fibrous layer of dense irregular connective tissue

-perforating fibers secure to bone matrix

osteogenic layer abuts bone

-contains primative stem cells-osteogenic cells

many nerve fibers and blood vessels

delicate connective tissue membrane covering internal bone surface

covers trabeculae of spongy bone

lines canals that pass through compact bone

contains osteogenic cells

thin plates of spongy bone covered by compact bone

no shaft or epiphyses

bone marrow throughout spongy bone; no marrow cavity

hyaline cartilage covers articular surfaces

hematopoetic= blood production

hematopoetic stem cells, fat cells, extensive vasculature

adult= in trabecular cavity ofspongy bone (sternum, coxal bone)

newborns: all marrow is red

fat storage

adult long bones have little red marrow, converted to fat as a demand for hematopoesis decreases

fills adult medullary cavities

can convert to red, if needed

miotically active stem cells in periosteum and endosteum

diferentiate into osteoblasts

bone forming cells

secrete unmineralized bone matrix

(osteoid= collagen and calcium binding proteins)

mature bone derived from osteoblasts

become "walled in" to bone spaces (lacunae)

maintain bone matrix in response to stress via communication with osteoblasts and osteoclasts

flattened dervatives of osteoblasts, line surfaces where no bone remodelling is occuring

may help maintain matrix

internal bone surface=endosteal cells

external= periosteal cells

bone resorbing cells

derived from hematopoetic (blodd) stem cells

giant, multinucleate cells

create resorption bay

hollow tubes of bone matrix = lamelle

-collagen fibers in adjacent rings run in different directons

central canal

-nerves and vasculature

-canals lined with endosteum at right angles to central canal

-cannect periosteum, meduallry cavity, and central canal

connect lacunae

osteoblasts secreting bone matrix get "boxed in"

allow communication

permit nutrients and wastes to be relayed from one osteocyte to another throughout osteon

incomplete lamellae

fill gaps between forming osteons

remnants of osteons cut by bone remodeling

extend around entire diaphysis

surround osteons

resist twisting of long bone

cells and osteoids

-osteogenic cells, osteobasts, osteocytes, bone-lining cells, and osteoclasts

-resilience of bone due to sacrificial bones between collagen molecules, stretch and break easily on impact to dissipate energy and prevent fracture

hydroxyapatites

-mineral salts

-65% of bone by mass

-mainly of tiny calcium phosphate crystals in and around collagen fibers

organic bone matrix secreted by osteoblasts

ground substance (proteoglycans and glycoproteins)

collagen fibers