Tissues Flashcards
A group of cells with similar structure and function, as well as similar extracellular substances located between cells.
Tissues
study of tissues
histology
4 types of tissues
- epithelial
- connective
- muscle
- nervous
Found throughout the body where it covers internal and external surfaces. It also forms most of the glands.
epithelial tissue
epithelial tissue is composed of layer of epithelial cells with one surface which is not in contact with other cells.
free surface or apical surface
attaches the epithelial cells (basal surface) to
underlying tissues.
basement membrane
Functions of epithelial tissue
- protect underlying structures
- acting as barriers
- permitting the passage of substances
- secreting substances
- absorbing substance
epithelial tissue can be classified according to
- number of cell layers
- shape of the cells
- consists of a single layer of cells
- typically found where absorption, secretion, and filtration occur
simple epithelium
more than one layer of cells
stratified epithelium
- single layer of cell; some cells are tall and thin and reach the free surface, and others do not; the nuclei of these cells are at different levels and appear stratified; the cells are almost always ciliates and are associated with goblet cells that secrete mucus onto the free surface.
pseudostratified columnar epithelium
- cells are flat or scale like
- single layer of flat, often hexagonal cells; the nuclei appear as bumps when viewed in cross seection because the cells are so flat.
simple squamous
- cells are cube shaped
- as wide as they are tall
- centrally located, spherical nuclei
simple cuboidal epithelium
- cells are taller than they are wide
- simple layer of tall, narrow cells; some cells have cilia (bronchioles of the lungs, auditory tubes, uterine tubes, and uterus) or microvili (intestines)
simple columnar epithelium
forms a thick epithelium because it consists of many layers of cells.
stratified squamous epithelium
2 classifications of stratified squamous
- keratinized
- non-keratinized
forms outer layer of skin and provides protection against abrasion
keratinized
the moist part of the epithelium and prevents surfaces from drying out
non-keratinized
- stratified cells that apppear cuboidal when th eorgan or tube is not stretched and squamous when the organ or tube is stretched by fluid
- specialized epithelia to change in response to increased tension.
- forms hollow organs
transitional epithelium
2 classifications of transitional epithelium
- squamous (when stretched)
- columnar/cuboidal (when not stretched)
function of epithelium in terms of number of cell layers
movement of materials (diffusion, filtration, secretion and absorption)
simple
function of epithelium in terms of number of cell layers
protection
Stratified
function of epithelium in terms of number of cell layers
cleaning
pseudostratified
function of epithelial tissue In terms of cell shape
diffusion and filtration
squamous
function of epithelial tissue In terms of cell shape
absorption and secretion
cuboidal and columnar
cell connections
- bind adjacent cells together and form permeability barriers
- impermeable prevent molecules from passing through the intracellular space
tight junctions
cell connections
- mechanical links that function to bind cells together
- anchoring junctions bind adjacent cell together like a molecular velcro and help form an internal tension-reducing network of fibers
desmosomes
cell connections
modified desmosomes
hemidesmosomes
CELL CONNECTIONS
- allows intracellular communication
- small channels that allow small
molecules and ions to pass from one epithelial cell to an adjacent one.
gap juctions
characterized by large amounts of
extracellular materials that separate cells from
another.
Connective tissue
3 components of connective tissue
- protein fibers
- ground substances
- fluid
surface of the cells that is anchored in place is called?
basal surface
- single layer of cube-shaped cells, some cells have microvili(kidney tubules) or cilia (terminal bronchioles of the lungs)
simple cuboidal epithelium
secretion and absorption by cells of the kidney tubules, secretion buy cells of glands and choroid plexuses (brain); movement of particles embedded in mucus out of the terminal bronchioles by ciliated cells.
Simple cuboidal epithelium
Diffusion, filtration, some secretion, and some protection against friction.
simple squamous epthelium
movement of particles out of the bronchioles of the lungs by ciliated cells; partially responsible for the movement of oocytes through the uterine tubes by ciliated cells; secretion by cells of the glands, the stomach, and the intestis; absorption by cells of intestines.
simple columnar epithelium
synthesize and secrete mucus onto the free surface and moce mucus (or fluid) that contains foreign particles over the surface of the free surface and from passages
pseudostratified columnar epithelium
several layers of cells that are cuboidal in the basal layer and progressively flattened toward the surface; can be keratinized or nonkeratinized
stratified squamous epithelium
the surface cells retain a nucleus and cytoplasm
nonkeratinized stratified squamous epithelium
the cytoplasm of cells at the surface is replaced by a protein called keratin, and the cells are dead
keratinized stratified epithelium
protects against abrasion, forms a barrier against infection, and reduces loss of water from the body
stratified squamous epithelium
location
outer layer of the skin
keratinized stratified epithelium
location
mouh, larynx, throat, esophagus, anus, vagina, inferior urethra, and corneas
nonkeratinized stratified squamous epithelium
stratified cells that appear cuboidal when the organ or tube is not stretched and squamous when the organ or tube is stretched by fluid
transitional epithelium
accomodates fluctuations in the volume of fluid in an organ or a tube; protects against the caustic effects of urine
transitional epithelium
location
lining of unrinary bladder , ureters, and superior urethra
transitional epithelium
location
lining of the nasal cavity, nasal sinuses, auditory tubes, pharynx, trachea, and bronchi of lungs
pseudostratified columnar epithelium
glands and some ducts, bronchioles of lungs, auditory tubes, uterus, uterine tubes, stomach, intestines, gallbladder, bile ducts, and ventricles of the brain.
simple columnar epithelium
kidney tubules, glands and their ducts, choroid plexuses of the brain, lining of termina bronchioles of the lungs, and surfaces of the ovaries
simple cuboidal epithelium
lining of blood vessels anf the heart, lymphatic vessels, alveloi of the lungs, portions of the kidney tubules, lining of serous membranes of the body cavities (pleural, pericardial, peritoneal)
simple squamous epithelium
a fine network of fibers (mostly collagen fibers with a few elastic fibers) with spaces between the fibers; fibrobasts, macrophages, anf lymphocytes are located in the spaces
areolar connective tissue
little extracellular matrix surrounding cells; the adipocytes, or fat cells, are so full of lipid that the cytoplasm is pushed to the periphery of the cell
Adipose Tissue
fine network of reticular fibers irregularly arranged
reticular tissue
Matrix composed of collagen fibers running in somewhat the same direction in tendons and ligaments; collagen fibers run in several directions in the dermis if the skin and in organ capsules
Dense regular collagenous connective tissue
matrix xomposed of collagen fibers and elastin fibers running in somewhat the same direction in elastic ligaments; elastic fibers run in connective tissue of blood vessel walls
dense regular elastic connective tissue
loose packing, support, and support and nourishment for the structures with which it is associated
areola connective tissue
Packing material, thermal insulator, energy storage, and protection of organs against injury from being bumped or jarred
adipose tissue
provides a superstructure for lymphatic and hemopoietic tissues
reticular tissue
within the lymph nodes, spleen, bone marrow
reticular tissue
