Tissues Flashcards
is a group of cells with similar structure and function, plus the extracellular substance surrounding them.
tissue
is the study of tissues.
Histology
types of tissues
epithelial
connective
muscle
nervous
a covering or lining tissue
epithelial
a diverse primary tissue type that makes up part of every organ in the body
connective
a tissue that contracts or shortens, making movement possible
muscle
responsible for coordinating and controlling many body activities
nervous
covers and protects surfaces, both outside and inside the body. Included under the classification of epithelial tissue are the exocrine and endocrine glands.
epithelial tissues
- Mostly composed of cells
- Covers body surfaces
- Distinct cell surfaces
- Cell and matrix connections
- Nonvascular
- Capable of regeneration
Epithelial Tissue Characteristics
- Protects underlying structures
- Acts as a barrier
- Permits passage of substances
- Secretes substances
- Absorption of substances
Functions of Epitelial tissues
Classification of Epithelial
are classified primarily according to the number of cell layers and the shape of the superficial cells. The cell layers can be simple, stratified, or pseudostratified. The cell shapes can be squamous, cuboidal, columnar, or a special transitional shape, that varies with the degree of stretch.
epithelial tissues
consists of a single layer of cells, with each cell extending from the basement membrane to the free surface.
simple epithelium
consists of more than one layer of cells, but only the basal layer attaches the deepest layer to the basement membrane.
stratified epithelium
is a special type of simple epithelium, that appears to be falsely stratified.
It consists of one layer of cells, with all the cells attached to the basement membrane.
Due to variations in the shape of the cells, the epithelia appears stratified.
Pseudostratified columnar epithelium
three types of epithelium based on idealized shapes of the epithelial cells
- Squamous
- Cuboidal
- Columnar
cells are flat or scalelike
squamous
cells are cube-shaped—about as
wide as they are tall.
Cuboidal
cells tend to be taller than they are wide.
Columnar
is a single layer of thin, flat cells.
Some substances easily pass through this thin layer of cells, but other substances do not.
The lungs, simple squamous epithelium, allows for gas exchange.
The kidneys, simple squamous epithelium, helps filter wastes from the blood while keeping blood cells inside the blood vessels
Simple squamous epithelium
is a single layer of cube-like cells that carry out active transport, facilitated diffusion, or secretion.
They have a greater secretory capacity than simple squamous epithelial cells.
Simple cuboidal epithelium
is a single layer of tall, thin cells.
The large size of these cells enables them to perform complex functions, such as secretion.
The simple columnar epithelium of the small intestine produces and secretes mucus and digestive enzymes.
Simple columnar epithelium
secretes mucus, which covers its free surface.
Cilia in the airways move the mucus and accumulated debris toward the throat, where it is swallowed.
Pseudostratified columnar epithelium
forms a thick epithelium because it consists of several layers of cells.
Though the deepest cells are cuboidal or columnar and are capable of dividing and producing new cells, the naming is based on the shape of the surface cells.
Stratified squamous epithelium
There are two types of stratified squamous epithelia:
keratinized stratified squamous nonkeratinized stratified squamous epithelia.
The outer layer of the skin is comprised of a
Keratinized Stratified Squamous Epithelium
Stratified squamous epithelium of the mouth is a moist
provides protection against abrasion and acts as a mechanical barrier.
Water, however, can move across it more readily than across the skin (keratinized stratified squamous
Nonkeratinized Stratified Squamous Epithelium
consists of more than one layer of cuboidal epithelial cells.
This epithelial type is relatively rare and is found in sweat gland ducts, ovarian follicular cells, and the salivary glands.
It functions in absorption, secretion, and protection.
Stratified cuboidal epithelium
consists of more than one layer of epithelial cells; the surface cells are columnar but the deeper cells are irregular or cuboidal in shape.
Like stratified cuboidal epithelium, stratified columnar epithelium is relatively rare, found in the mammary gland ducts, the larynx, and a portion of the male urethra.
This epithelium carries out secretion, protection, and some absorption.
Stratified columnar epithelium
is a special type of stratified epithelium that can be greatly stretched.
The shape of the cells change as the epithelium is stretched.
lines cavities that can expand greatly, such as the urinary bladder.
It also protects underlying structures, like the urinary bladder, from the caustic effects of urine.
Transitional Epithelium1
that is not in contact with other cells and faces away from underlying tissues.
can be smooth or lined with microvilli or cilia.
Cilia move materials over the top of the cell. Microvilli increase surface area.
free cell surface
have several structures that hold one cell to one another or to the basement membrane.
These structures do three things: mechanically bind the cells together, help form a permeability barrier, and provide a mechanism for intercellular communication.
cells
are mechanical links that bind cells together.
desmosomes