ch4 Flashcards
Charactersitics of epithelial tissue
cellularity (composed of all cells with little extracellular matrix)
polarity (apical surface and basal surface, lateral surface w intercellular junctions.)
attachment to basement membrane (in the basal surface the epithelial layer is bound to basement membrane)
avascularity (lack of tissues and blood vessels)
innervation (detect changes in enviro)
high regen capacity (apical surface damaged more frequently, so they replace themselves quick through mitotic divison of deep epithelial cells(stem cells) near basement membran)
how do epithelial cells obtain nutrients
from apical surface or diffusion on basal surface from connective tissue
what can be on the apical surface
cilia or microvilli
what is attached to the basal surface
epithelium in basal surface attached to a basement membrane which is part of both the epithelium and connective tissue underneath
functions of epithelial tissue
physical protection
selective permability
secretion
sensation
what do epithelial tissues protect against
dehydration, abrasion, and phyisical chemical or biological destruction
what are exocrine glands
epithelial cells specialized to produce secretions. can either be scattered or clumped to form a gland
neuroepithelium
a specialized epithelium hat some organs contain that house specific cells that a responsble for senses like taste, smell, vision, hearing, and equilibrium
why dont epithelial cells contain blood vessels?
to prevent bleeding bc this cell is frequently injured, and bc its protective function would be compromised
3 layers of basemement membrane and what do they contain
lamina lucida, lamina densa( both of these have protein and collagen) and reticular lamina (has protein and carbs)
functions of the basement membrane
1 physical support for epithelium
2 anchors epithelium to connective tissue
3 barrier to reg movement of large molecules btwn epi and underlying tissue
intercellular junctions
speciliazed connections in plasma membranes of the lateral surfaces of eipthelial cells that bind them together
types of intercellular junctions
tight, adhering, desmosomes, and gap junctions
tight junctions
encircle cells near their surface and completely attach each cell to its neighbor. very tightly sealed, forcing all materials to move through the cells instead of between them. allows them to control anything that enters the body
adhering junctions
located deep to tight junctions. microfillaments extend from cytoplasm into plasma membrane that completely circles the cell. they have a bit more space between them allowing things that have already passed through the tight junctions on the surface to pass between the cells instead of thru on their way to the basement membrane.
desmosome
like a button between epithelial cells. each cell contributes half of the complete desmosome. they dont cover the whole cel and only attach to neighboring cells at potential stress points
gap junctions
formed across gap btwn neighboring cells. bridged by connexons. they provide passageways for small molecules into neighboring cells, allowing for ions, glucose, and amino acids to pas thru. also in muscle tissue to help with contractions.
what intercellular junction provides resistance to mechanical stress at a single point
desmosomes
hemidesmosomes
some basal cels have half demisomes that anchor them to the basement membrane
simple epithelium and wher eis it found
one cell layer so all cells touch basement membrane. found where stress is minimal and diffusion/filtration/absorption/secretion is the main function (air sace, intestines, blood vessels)
stratified epithelium and whre is it found
2 or more layers of epithelial cells. only deep cells touch basement. multiple layesr make it strong so it is found in areas subjected to more stress (skin, esophagus, vagina) cells in basal layer continually regen as the apical cells are lost from damage
pseudostratified epithelium
appears layered bc nucleui are at dif levels but all of the cells are actually attached to basement membrane. some cells dont reach apical surface. (nasal cavity, respiratory passageways)
squamous cells
flat, wide, irregular shaped. nucleus looks like flat disc, cells look like irregular floor tiles.
cuboidal cell shape
as tall as they are wide, not perfect cubes bc rounded edges. nucleus spherical and in center of cell.
columnar shaped cells
slender, tall. look like hexagonal columns. nucleus oval and sits lenthwise in basal region.
transitional shaped cells
can change shape depending on how stretched epithelium becomes. (bladder, etc) polyhedral when cell is relaxed, looks squamous when stretched.
types of simple epithelium
simple squamous, simple cuboidal, simple columnar, pseudostratified columnar
types of stratified epithelium
transitional, stratified columnar, stratified cuboidal, stratified squamous(keratinized and nonkeratinized)
simple squamous epithelium
STRUCTURE:single layer of thin flat cells like floor tiles, nucleus bulges at center of each cell
FUNCTION: rapid diffusion and filtration, some secretion in serous membranes
LOCATION: amnion, inner later of membran around embry, air sacs, lining of heart, blood vessels, serous membrans of body cavities
simple cuboidal epithelium
STRUCTURE:single layer tall and wide ells, spherical, central nucleus
FUNCTION:absorption and secretion
LOCATION:kidney tubules, thyroud follicles, ducst and secretory regions of most glands, surface of ovaries,
NONCILIATED SIMPLE COLUMNAR EPITHELIUM
STRUCTURE:single layer of tall narow cells, oval nuc lengthwise at basal, apical reg has macrovili, can contain goblet cells
FUNCTION:absorbtion and secretion, secretion of mucin
LOCATION:lining of digestive tract, lining of stomach does not contain goblet cells
ciliated simple columnar epithelium
STRUCTURE: same as nonciliated but without microvilli.
FUNCTION: secretion of mucin and movement along apical surface with the cilia. oocyte movement thru uterine tube.
LOCATION: lining of uterine tubes and larger bronchioles of resp tract
pseudostratified columnar epithelium
STRUCTURE:single layer. varying heights that look multilayered. all cells connect basement membrane but not all to apical. ciliated form has goblet cells and cilia, nonciliated form does not.
FUNCTION: protection, ciliated forms secrete mucin and movement
LOCATION: ciliated lines resp tract like nasal, pharynx, larynx, trachea, bronchi. nonciliated isRARE, lines epididymus and male urethra.
endothelium
simple squamous epithelium that lines lumen of blood, lymphatic vessels, and heart
mesothelium
simple squamous epithelium of the serous membrane that lines internal walls of pericardial, pleural, and peritoneal cavities as well as external surfaces of organs withtin those cavities
brush border
what microvili appear as when viewd with light microscopy. lookslike a fuzzy structure
mucin
a glycoprotein secreted by mucin that when hydrated forms mucus.
keratinized vs nonkeratinized stratified squamous epithelium
STRUCTURE:multiple layers of cells, basal cells cuboidal/polyhedral, apical cells squamous.
keratinized-more superficials cells dead and filled with keratin
nonkeratinized-superficial cells are alive and kept moist
FUNCTION:protection of underlying tissue
LOCATION:
keratinized- epidermis of skin
nonkeratinized-lining of vagina, oral cavity, pharynx, espohagus, and anus
stratified cuboidal epithelium
STRUCTURE:2+ layers, cells are apical surface cuboidal
FUNCTION: protection and secretion
LOCATION: large ducts in exocrine glands and some parts of male urethra
stratified columnar epithelium
STRUCTURE: 2+ layers of cells, cells at apical surface columnar
FUNCTION: protection and secretion
LOCATION: rare, found in regions of male urethra and large ducts of exocrine glands
transitional epithelium
STRUCTURE: appearance varies depending on whether stretched or relzxed. some cels may be binucleated
FUNCTION: distension and relaxtation to accomodate urin volume changes
LOCATION: lining of bladder, ureters, and urethra
glands
individual or multicellular, composed of mostly epithelial tissue. secrete substances for use in body or for elimination from body (mucin, electolytes, hormones, enzyms, waste)
endocrine glands
lack ducts and secrete direct to blood and intersitital fluid. secrete hormones that are chem messenges to influence activites in other parts of bvody
exocrine glands
maintain contact with epithelial surface through a duct. secretes onto skin or epithelial surfaces lining passageways
(Sweat, milk, enzymes)
connective tissue
most diverse and widely used version of tissue. supports, protects, and binds organs. glue that holds body structure together
what do all connective tissues share
cells, protein fibers, and ground substance
how are connective tissue cells and epithelial cells different
connective tissue cells are scattered, whereas some epi cells are clumped together
three types of protein fibers and what they signify ab the funciton of connective tissues
collagen fibers (strong and strech resistant)
elastic fibers (flexible and reslient)
reticular fibers (for interwoven framework)
ground substance, what is it and what types are there
nonlibving material produced by connective tissue cells. made of protein and carb molecules and some water.
can be viscous (blood), semisolid (cartilage), or solid (bone).
extracellular matrix
formed by ground substance and protein fibers. most connective tissue is composed majority of this with smaller amount of cells.
functions of connective tissue
phys protection, support and structural framework, binding of structure, storage, transport, immune protection
how does connective tissue provide physical protection
bones protect organs
how does connective tissue provide support and. framwork
bones provide framwork and support soft tissues. cartilage supports body structures like trachea, ears. connectiv tusse sheets form capsules to support oragns like spleen and kidney
how does connective tissue bind to structure
ligaments bind bone to bone, tendons bind muscle to bond, connective tissue binds skin to muscle and bone
what does connective tissue store
fat, bone stores calcium and phosphorus
how does connective tissue suport imun protection
some type of tissue contain white. blood cells. extracelluluar matrix is viscuous and interferes w movement of disease cuasing organisms.
3 categories of connective tissue
connective tissue proper, supporting connective tissue, and fluid connective tissue
types of connective tissue proper and what do they contain
loose connective tissue (less fibers, more ground substance)
-areolar, adipose, reticular
dense connective tissue (more fibers, less gorund sub)
-regular, irregular, elastic
types of supporting connective tissue and what do they contain
cartilage (semisolid matrix)
-hyaline, fibrocartilage, elastic
bone (solid matrix)
-compact, spongy
types of fluid connectiv tissue
blood and lymph
connective tissue proper
these exhibit a variable mix of cell types and and protein fibers suspended in ground substance
2 classes of cells that form connective tissue proper
resident -stationary cells contained in conn tissue. support and repair extracellularmatrix
wandering - move thru con tissue, used for immue protection and repair of damaged matrix
types of resident cells
fibroblasts, adipocytes, fixed macrophages, mesenchymal cells
fibroblasts
abundant, large, flat, tapered ends.
produce fibers and ground substance in the extracellular matrix
adipocytes
fat, large lipid droplet. cell components pushed to one side
store lipid reserves
fixed macrophages
large, derived from monocytes in blood. reside in matrix after leaving blood
phagoctize foreign material
mesenchymal cells
stellate or spindleshaped embryonic stem cells
divide when injured to produce new conn tissue
types of wandering cells
mast cells, plasma cells, free macrophages, other leukocytes
mast cells
small w granule filled cytoplasm
release histamine and heparin to create inflamation
plasma cells
small, distinct nucleus, derived from activated b-lymphocytes
form antibodies that bind to foreign substances like bacteria or viruses
free macrophages
mobile phagocytic cells made from monocytes of blood
phagocytize foreign material
other leukocytes
white blood cells that enter conn tissue
attack foreign materials or directly combat bactera
what are most wandering cells of the conective tissue proper a type of
leukocytes
protein fibers of conn tissue proper
collagen fibers, elastic fibers, reticular fibers.
areolar connective tissue
type of loose conn tiss
STRUCTURE: fibroblasts, less amounts of collagen and elastic fiber, viscous ground substance
FUNCTION: packs around and binds organs
LOCATION:nerves, vessels, subcutaneous layer
adipose connective tissue
type of loose conn tiss
STRUCTURE: adipoctyes
FUNCTION: protects, stores fat, insulates
LOCATION: subcutaneous layer, suround kidney and someother organs
reticular connective tissue
type of loose conn tiss
STRUCTURE: meshwork of reticular fibers
FUNCTION:forms stroma of lymphatic organs
LOCATION:stroma of spleen, liver, lymph nodes ,and bone marrow
dense regular connective tissue
STRUCTURE: densely packed collagen fibers parallel to direction of stress
FUNCTION: strength and flexibility in a single direction
LOCATION:tendons and ligaments
dense irregular connective tissue
STRUCTURE:collagen fibers interwoven, irregularly clumped and project in all directions
FUNCTION: tensile strength in all directions
LOCATION: dermis of skill, capsules of organs
elastic connective tissue
STRUCTURE: elastic and collagen fibers arranged irregularly
FUNCTION: framwork and supports organs
LOCATION: walls of large arteries
cartilage
has firm, gell like extracellular matrix made of protein and gorund substance. more strong and resilient(due to collagen) that all types other than bone, and more flexible than bone(due to elastic fibers).
chondrocytes
mature cartilage cells. produce chemical that precvents blood vessel formation in extracellular matrix. exchange nutrients and waste with blood vessels OUTSIDE of cartilage through diffusion
lacunae
small spaces within extracellular matrix
perichondrium and its 2 layers
covers cartilage.
outer, fibrous region of dense irreg conn tissue
inner, cellular layer (contains stem cells for growth of cartilage)
3 types of cartilage
hyaline cartilage , fibrocartilage, elastic cartilage
hyaline cartilage
STRUCTURE: glassy matrix, lacunae house chondrocytes, covered by perichondrium
FUNCTION: smooth surfaces for joint movement, model for bone growth, support soft tissue
LOCATION: articular ends of long cones, fetal skeleton, costal cartialage, larynx, trachea, nose
fibrocartilage
STRUCTURE:visible, parallel collagen fibers, lacunae house chondrocytes, no perichondrium
FUNCTION: resists compression and absorbs shocks in joints
LOCATION: intervertebral discs, pubic symphysis, menisci of knee joints
elastic cartilage
STRUCTURE: abundant elastic fibers that form web mesh around lacunea, perichondrium present
FUNCTION: maintain structure and shape but allow flexibility
LOCATION: eternal ear, epiglottis of larynx
bone connective tissue
makes up mass of most body structures called bones. more solid that cart and provides more support.
what is bone made of
1/3 organic components(collagen, protein-carb molecules) flexibility and tensile strenght
2/3 inorganic (calcium salts) provide compressional strength
periosteum
dense irregular conn tissue covering bone surfaces
osteons and what travels thru them
cylindrical structures that form compact bone. run parallel to shafts of bone and contain lamalle that circle and central canal
blood vessels and nerves
lamallae
layer of bone connective tissue in teh form of a ring
osteocytes
bone cells housed by lacunae between neighboring lamellae. communicate with one another and the blood vessels in the central canal through canaluculi in order to excahnge materials with blood vessels
canaluculi
minute passageways in the matrix that osteocytes use to communicate with blood vessels
compact bone vs spongy bone
STRUCTURE:
-compact: calcified matrix arranged in osteons
-spongy: lacks organization of compact, contains microscopic spaces, arranged in meshwork pattern
FUNCTION: support soft structures, protect vital organs, levers for movement, store calcium and phos.
-spongy bone only: cite of hematopeoiesis
LOCATION:bones of the body
hematopoietic cells
form reticular connective tissue responsible for producing blood cells. contained in spongy bone
blood
STRUCTURE: contains erythrocytes, leukocytes, platelets. soluble protein fibers and watery ground substance form plasma
FUNCTION:
-erythrocytes xport oxygen and CO2
-leukocytes control immune response
-plasma contains clotting elements and transports nutrients/waste/hormones
-platelets also help with clotting
LOCATION: within blood vessels and heart
-leukocytes located in lymphatic organs to migrate to inflamed tissues
erythrocytes
red blood cells that xport oxygen and CO2 btwn lungs and tissues
platelets
involved in vlood clotting
plasma
xports nutrients and waste and hormones through body
lymph
derived from plasma and is returned to blood. has no elements.
mucous membrane
lines. body passageways that can open to the environment. digestive, respiratory, etc. composed of conn tiss call lamina propria and epithelium.
cutaneous membrane
largest body membrane (aka, skin)
made of keratinized squamous epithelium (called epidermis) and a layer of connective tissue called the dermis.
synovial membrane
lines some joints,
made of vascularized areolar, fibrous, or adipose tissue under a superficial cellular lining.
how are tissues formed
the germ layer
extracellular matrix of this tissue varies from liquid to solid
connective
most glands are composed of
epithelial tissue
is epithelial tissue innervated?
yes, richly so
what would the study of blood be in regards to types of anatomy
histology
what type of tissue is for storage and transport
connective
how many human tissue types are there (primarily)
4, connective tissue, epithelial tissue, muscle tissue, and nervous tissue
locations of epithelial tissues
covers body surfaces, lines organs, covers organs, lines body cavities
NOT attached to bone
are epithelial tissues boudn close together
no
do epthelial tissues consist mostly of extracellular matrix?
no
does a large amount of extracellular matrix separate epithelial cells?
yes
are epithelial tissues composed almost entirely of cells?
yes
what surfaces of epithelial cells contain intercellular junctions
lateral
which of the 4 tissue types have little extracellular matrix
epithelial, nervous, and muscle
what do glands secrete
which tissues have a lot of extracellular matrix and which dont out of the 4 types
connective has a lot,
muscle, nervous, and epi have lil
which tissue type has cellular matrix that can be solid or liquid
connective
what categories are used to classify epithelia
cell shape, cells at apical surface
endothelum
simple, squamous cells that line blood and lymphatic vessels
what does endothelium line
it lines the heart
what type of cells does connective tissue proper contain
fibroblasts
what type of cells does fat tissue contain
adipocytes
what type of tissue does cartilage contain
chondrocytes
what type of tissue does bone contain
osteocytes
what do all connective tissues share
ground substance, cells, protein fibers
fixed macrophages
large cells that phagocytize damaged cells and pathogens
