what is a tissue?

Groups of cells with similar structure and function.

Histology

The study of tissues.

What are the four main tissues?

Epithelial tissue (epithelium).
Connective tissue.
Muscle tissue.
Nervous tissue.

where the epithelial tissue is located?

Body coverings.
Organs linings.

Epithelial tissue functions

Protection.
Absorption.
Filtration.
Secretion.

epithelial tissue classification

Simple�one layer.
Stratified�more than one layer.

cell form of epithelial tissue

Squamous.
Flattened, like fish scales.
Cuboidal.
Cube-shaped, like dice.
Columnar.
Column-like.

simple squamous

Single layer of flat cells.

location of simple squampus

usually forms membranes.
Lines air sacs of the lungs (alveoli).
Forms walls of capillaries.
Forms serous membranes (serosae) that line and cover organs in ventral cavity.

functions of simple squampus

in diffusion, filtration, or secretion in membranes.

simple cuboidal

Single layer of cube-like cells.

location of simple cuboidal

Common in glands and their ducts
-Forms walls of kidney tubules.
-Covers the surface of ovaries.

functions of simple cuboidal

in secretion and absorption; ciliated types propel mucus or reproductive cells.

Simple columnar

Single layer of tall cells
-Goblet cells secrete mucus.

location of simple columnar

-Lines digestive tract from stomach to anus
-Mucous membranes (mucosae) line body cavities opening to the exterior.

functions of simple columnar

in secretion and absorption; ciliated types propel
mucus or reproductive cells.

what is a Stratified squamous?

Named for cells present at the free (apical) surface, which are flattened.

what is the functions of stratified squamous?

as a protective covering where friction is common.

location of stratified squamous

-Skin (outer portion)
-Mouth
-Esophagus

what is a Stratified cuboidal?

two layers of cuboidal cells; functions in protection.

what is a Stratified columnar?

surface cells are columnar, and cells underneath vary in size and shape; functions in protection.

Stratified cuboidal and columnar

Rare in human body.

shape of stratefied epithelia

of cells depends upon the amount of stretching.

functions of stratefied spithelia

in stretching and the ability to return to normal shape.

locations of stratefied spithelia

urinary system organs.

functions of connective tissue

-Provides protection
-Binds body tissues together
-Supports the body

connective tissue characteristics

Variations in blood supply
{Some tissue types are well vascularized, Some have a poor blood supply or are avascular}
Extracellular matrix {Nonliving material that surrounds living cells}.

connective tissue types

From most rigid to softest, or most fluid:
-Bone
-Cartilage
-Dense connective tissue
-Loose connective tissue
-Blood

function of muscle tissues

is to contract, or shorten, to produce movement.

three types of muscle tissues

-Skeletal muscle
-Cardiac muscle
-Smooth muscle

skeletal muscle produces

gross body movements or facial expressions.

Characteristics of skeletal muscle cells

-Striations (stripes)
-Multinucleate (more than one nucleus)
-Long, cylindrical shape

Cardiac muscle

-Involuntarily controlled
-Found only in the heart

Pumps of cardiac muscle

blood through blood vessels.

Characteristics of cardiac muscle cells

-Striations
-Uninucleate, short, branching cells
-Intercalated discs connect cells together

Smooth (visceral) muscle

Involuntarily controlled.

found of smooth muscle

in walls of hollow organs such as stomach, uterus, and blood vessels.

Characteristics of smooth muscle cells

-No visible striations
-Uninucleate
-Spindle-shaped cells

nervous tissues composed :

of neurons and nerve support cells.

functions of nervous tissues

is to receive and conduct electrochemical impulses to and from body parts:
-Irritability
-Conductivity

Support cells

called neuroglia insulate, protect, and support neurons.