What is a tissue?

Tissues are groups of similar cells that perform a common function. There are four categories of tissues in the human body: epithelial, connective, nervous, and muscle.

What are the four types?

Muscle; produces movement.

Nerve; receives stimuli and conducts impulses.

Epithelial; lines and covers surface.

Connective; protects, supports, and binds together.


The functions of Epithelial are: protection, secretion, absorption, excretion, and sensory perception.

1. Lines body cavities and covers the body's external surface - epithelial

2. Pumps blood, flushes urine out of the body, allows one to swing a bat - muscular

3. Transmits waves of excitation - nervous

4. Anchors and packages body organs - connective

5. Cells may absorb, protect, or form a filtering membrane - epithelial

6. Most involved in regulating body functions quickly - nervous

7. Major function is to contract - muscular

8. The most durable tissue type - connective

9. Abundant nonliving extracellular matrix - connective

10. Forms nerves - nervous


Epithelial is classified into simple and stratified. Simple epithelial can be subdivided to the shape and function of its cells. Where the body linings have to withstand wear and tear, the epithelia are composed of several layers of cells and are then called compound or stratified epithelium.

Specializations of Epithelia

Epithelial tissue is found throughout the body, covers all body surfaces both inside and out. It is the main glandular tissue. Attached to underlying connective tissue by noncellular nonliving basement membrane. Usually has no vascular tissue. Cells reproduce rapidly. And has cells tightly packed together.

examples of where these four types can be found

Covering and lining epithelium covers or lines almost all of your internal and external body surfaces; for example, the outermost layer of your skin and other organs, and the internal surface lining of your lymph vessels and digestive tract. Glandular epithelium secretes hormones or other products such as stomach acid, sweat, saliva, and milk. Loose connective tissue holds structures together. For example, loose connective tissue holds the outer layer of skin to the underlying muscle tissue. This tissue is also found in your fat layers, lymph nodes, and red bone marrow. Fibrous connective tissue also holds body parts together, but its structure is a bit more rigid than loose connective tissue. Fibrous connective tissue is found in ligaments, tendons, cartilage, and bone. Neurons are the basic structural unit of the nervous system. Each cell consists of the cell body, dendrites, and axon. Neuroglia, or glial cells, provide support functions for the neurons, such as insulation or anchoring neurons to blood vessels. Skeletal muscle is attached to bones and causes movements of the body. Cardiac muscle is found in the heart. Smooth muscle lines the walls of blood vessels and certain organs such as the digestive and urogenital tracts.

Comment Stream