lecture 4 tissues Flashcards
work together in functionally related groups called tissues
cells
a group of closely associated cells that perform related functions and are similar in structure
tissues
-covers body surface or lines a body cavity
-forms parts of most glands
-functions ;
protection, secretion, absorption, diffusion, filtration, sensory reception
epithelial tissue
- cellularity
- specialized contacts
- polarity
- support by connective tissue
special characteristics of epithelia
cells separated by minimal extracellular material
cellularity
cells joined by special junctions
specialized contacts
cell regions of the apical surface differ from the basal surface
polarity
- avascular but innervated
- regeneration
support by connective tissue
epithelia receive nutrients from underlying connective tissue
avascular but innervated
lost cells are quickly replaced by cell division
regeneration
classifications epithelia
- first name of tissue indicates number of cell layers
- last name of tissue describes shape of cells
- simple epithelia
- stratified epithelia
- squamous
- cuboidal
- columnar
single layer of cells attached to basement membrane
simple epithelia
- multiple layers of cells
- basal layer of cells attached to basement membrane
stratified epithelia
-single layer; flat cells with disc-shaped nuclei
functions
-passage of materials by passive diffusion and filtration
-secretes lubricating substances in serosae
location
-renal corpuscles
-alveoli of lungs
-lining of heart, blood, and lymphatic vessels
-lining of ventral body cavity
simple squamous epithelium
-single layer of tubelike cells with large, spherical central nuclei
function
-secretion and absorption
location
-kidney tubules, secretory portions of small glands, ovary surface
simple cuboidal epithelium
-single layers of column-shaped (rectangular) cells with oval nuclei
-some bear cilia at their apical surface
-may contain goblet cells
function
-absorption; secretion of mucus, enzymes, and other substances
-ciliated type propels mucus or reproductive cells by ciliary action
location
-Non ciliated form
-lines digestive tract, gallbladder, ducts of some glands
-ciliated form
-lines small bronchi, uterine tubes, and uterus
simple columnar epithelium
-all cells originate at basement membrane
-only tall cells reach the apical surface
-may contain goblet cells and bear cilia
-nuclei lie at varying heights within cells
–gives false impression of stratification
function
-secretion of mucus; propulsion of mucus by cilia
location
-non ciliated
-ducts of male reproductive tubes
-ducts of large glands
ciliated
-lines trachea and most of upper respiratory tract
pesudostratified columnar epithelium
properties
- contains 2 or more layers of cells
- regenerate from below (basal layer)
- major role is protection
- named according to shape of cells at apical layer
stratified epithelia
-many layers of cells are squamous in shape
-deeper layers of cells appear cuboidal or columnar
-thick epithelial tissue
–adapted for protection from abrasion
2 types- keratinized and non keratinized
function
-protects underlying tissues in areas subject to abrasion
location
-k ; forms epidermis
-nk; forms lining of mucous membranes
esophagus, mouth, anus, vagina, urethra
stratified squamous epithelium
location epidermis
- contains the protective protein keratin
- waterproof
- surface cells are dead and full of keratin
keratinized stratified squamous epithelium
forms moist lining of body openings
non keratinized stratified squamous epithelium
-generally two layers of cube shaped cells
function
-protection
location
-forms ducts of mammary glands, salivary glands, and largest sweat glands
stratified cuboidal epithelium
-several layers; basal cells usually cuboidal; superficial cells elongated
function
-protection and secretion
location
-rare tissue type
-found in male urethra and large ducts of some glands
stratified columnar epithelium
-characteristics of stratified cuboidal and stratified squamous
-superficial cells dome-shaped when bladder is relaxed, squamous is full
function
-permits dissension of urinary organs when they are filled with urine
location
-epithelium of urinary bladder ureters, proximal urethra
transitional epithelium
ductless glands that secrete directly into surrounding tissue fluid
-produce hormones
endocrine glands
-ducts carry products to epithelial surface
-includes
-mucus-secreting,
-sweat and oil
-salivary
-liver and pancreas
glands
exocrine glands
cells that produce mucin
mucin + water = mucus
-protects and lubricates many internal body surfaces
-goblet cells are a unicellular exocrine gland
goblet cells
factors binding epithelial cells together
adhesion proteins
contours
special cell junction
link plasma membranes of adjacent cells
adhesion proteins
of adjacent cell membranes
contours
also called zona occludens
- close off intercellular space
- found at apical region of most epithelial tissue types
- prevent certain molecules from passing between cells
tight junctions
- also called zonula adherens
- anchoring junctions
adhesive belt junctions
main junction for binding cells together
- scattered along abutting sides of adjacent cells
- cytoplasmic side of each plasma membrane has a plaque
- common in cardiac muscle and epithelial tissue
desmosomes
passageway between two adjacent cells
- lets small molecules move directly between neighboring cells
- connected by hollow cylinders of protein
- function of intercellular communication
gap junctions
-located at the boundary between the epithelium and connective tissue
-noncellular supporting sheet between epithelial and connective tissue deep to it
-proteins secreted by epithelial cells
function
-acts as a selective filter
-acts as scaffolding along which regenerating epithelial tissue cells can migrate
the basal lamina
forms the basement membrane
basal lamina and reticular layers
- fingerlike extensions of plasma membrane
- have a core of actin filaments that stiffen the microvillus
- abundant in kidney tubules and small intestine
- maximize surface across which small molecules enter or leave cells
microvilli
- whiplike, highly motile extensions of apical surface membranes
- contains a core of microtubules held together by cross-linking and radial proteins
cilia
-most diverse and abundant tissue functions -forms basis of skeleton -store and carry nutrients -surround blood vessels and nerves -lead fight against infection
connective tissue
mains classes of connective tissue
connective tissue proper
cartilage
bone tissue
blood
connective tissue cells produce
extracellular matrix
common embryonic origin
- gel like substance
- cells are star shaped cells
- all connective tissues arise from
mesenchyme
illustrates connective tissue features
loose areolar connective tissue
- in connective tissue proper
- make protein subunits
fibroblasts
secrete matrix in cartilage
-immature cartilage cells
chondroblasts
secrete matrix in bone
osteoblasts
areolar connective tissue contains
fat cells, white blood cells, and mast cells
extracellular matrix composed of ground substance and
fibers
strongest fiber
resist tensions
collagen fibers
bundles of special type of cartilage
reticular fibers
contains elastin
-recoil after stretching
elastic fibers
- produced by primary cell type of the tissue
- usually gel like substance consisting of proteoglycans and glycosaminioglycans
- cushions and protects body structures
- holds tissue fluid
- no blood
ground substance
connective tissue proper has 2 subclasses
- loose connective
2. dense connective
areolar, adipose and reticular tissue
loose connective
dense irregular, dense regular, and elastic tissue
dense connective tissue
- underlies epithelial tissue
- surrounds small nerves and blood vessels
- has structures and functions shared by other C.T
- borders all other tissues in the body
areolar connective tissue
- watery fluid occupying extracellular matrix
- tissue fluid derives from blood
interstitial fluid
function -provides reserve food fuel -insulates against heat loss -supports and protects organs location -under skin -around kidneys -behind eyeballs, within abdomen, and in breasts -hypodermis
adipose tissue
-produces heat
-occurs in babies to help thermoregulation
-found in adults
between scapulae
sides of anterior neck
anterior abdominal wall
-richly vascularized; cells contain may lipid droplets and numerous mitochondria
brown adipose tissue
-network of reticular fibers in loose ground substance function -forms a soft, internal skeleton -supports other cell types location -lymph nodes, bone marrow, spleen
reticular connective tissue
3 types of dense connective tissues
dense irregular connective
dense regular connective
elastic connective
resist strong pulling forces
-has more collagen than areolar connective tissue
dense connective tissue
-collagen fibers thick and irregularly arranged
-contains some elastic fibers and fibroblasts
function
-withstands tension
-provides structural strength
location
-dermis of skin
-submucosa of digestive tract
-fibrous capsules of joints
-surround kidneys, bones, and lymph nodes
dense irregular connective tissue
-collagen fibers are parallel to direction of pull
-fibroblasts are located between collagen fibers
-contains few elastic fibers
-great tensile strength
-poorly vascularized
-forms fascia
function
-attaches to muscle to bone
attaches bone to bone
location
-tendons and ligaments
-aponeuroses
-fascia around muscles
dense regular connective tissue
-elastic fibers predominate function ; allows recoil after stretching location ; within walls of arteries; in certain ligaments; surround bronchial tubes
elastic connective tissue
- firm, flexible tissue
- contains no blood vessels or nerves
- matrix contains up to 80% waters
- cell type is chondrocyte
cartilage
3 types of cartilage
hyaline, elastic, fibrocartilage
-imperceptible collagen fibers (glassy)
functions ; supports and reinforces ; resilient cushion ; resists repetitive stress
location ; fetal skeleton; ends of long bones; costal cartilage of ribs ; cartilages of nose, trachea and larynx
hyaline cartilage
-similiar to hyaline cartilage
-more elastic fibers in matrix
functions ; maintains shape of structure ; allows great flexibility
location ; supports external ear ; epiglottis
elastic cartilage
-matrix similar but less firm than hyaline cartilage
-thick collagen fibers predominate
function ; tensile strength and ability to absorb compressive shock
location ; intervertebral discs; pubic symphysis ; discs of knee joint
fibrocartilage
-bone matrix contains inorganic calcium salts; abundance of collagen fibers
-osteoblasts
-osteocytes
function
-suuports and protects organs
-provides levers and attachment sites for muscles
-stores calcium and other minerals
-stores fat
marrow is site for blood cell formation
location bones
bone tissue
-atypical connective tissue
-develops from mesenchyme
-consists of cells surrounded by nonliving matrix
-red and white blood cells in a fluid matrix
-transport of respiratory gases, nutrients and wastes
location within blood vessels
blood tissue
skin
cutaneous membrane
-lines hollow organs that open to surface of body
mucous membranes
simple squamous epithelium called mesothelium lying on areolar connective tissue
lines closed cavities;
pleura, peritoneal, pericardial cavities
-produces serous fluid
serous membrane
-composite tissue
-contains areolar connective tissue in addition with muscle tissue
muscle fibers
myofilaments
muscle tissue
muscle cells
muscle fibers
3 types of muscle tissue
skeletal
cardiac
smooth
-long cylindrical cells
-multinucleate
-obvious striations
function ; voluntary movement; manipulation of environment; facial expression
location ; skeletal muscles attached to bone
skeletal muscle tissue
-branching cells, striated
-generally uninucleate
-cells interdigitate at intercalated discs
function ; contracts to propel blood into circulatory system
location ; occurs in walls of heart
cardiac muscle tissue
-spindle-shaped cells with central nuclei
-arranged closely to form sheets
-no striations
functions ; propels substances along internal passageways; involuntary control
location ; mostly walls of hollow organs
smooth muscle tissue
-main components are brain, spinal cord and nerves
-contains 2 types of cells ; neurons and neuroglia
function ; transmit electrical signals from sensory receptors to effectors
location ; brain, spinal cord and nerve
nervous tissue
- nonspecific local response
- limits damage to injury site
inflammatory response
- takes longer to develop and very specific
- destroys particular microorganisms at site of infection
immune response
-heat, redness, swelling, pain, chemicals signal nearby blood vessels to dilate
acute inflammation
increases permeability of capillaries
histamine
accumulation of fluid
- helps dilute toxins secreted by bacteria
- brings oxygen and nutrients from blood
- brings antibodies from blood to fight infection
edema
replacement of destroyed tissue with same type of tissue
regeneration
proliferation of scar tissue
fibrosis
clot is replaced by granulation tissue
organization
epithelial tissue, bone connective tissue, areolar connective tissue, dense irregular connective tissue and blood forming connective tissue
good to excellent ; capacity for regeneration
smooth muscle tissue, dense regular connective tissue
moderate ; capacity for regeneration
skeletal muscle tissue, cartilage
weak ; capacity for regeneration
cardiac muscle tissue, nervous tissue
none or almost none ; capacity for regeneration