The main difference between epithelial and connective tissue is that epithelial tissue lines the cavity and the surfaces of organs and blood vessels throughout the animal body whereas connective tissue supports, connects and separates different types of tissues and organs in the body.

There are 4 basic types of tissue: connective tissue, epithelial tissue, muscle tissue, and nervous tissue. Connective tissue supports other tissues and binds them together (bone, blood, and lymph tissues). Epithelial tissue provides a covering (skin, the linings of the various passages inside the body).

1 Functions of tissues

• secretion.
• movement.
• strength.
• excretion.
• communication.

There are three main groups of connective tissues: loose connective tissue, dense connective tissue, and specialized connective tissue.

7 Types of Connective Tissue

• Cartilage. Cartilage is a type of supporting connective tissue.
• Bone. Bone is another type of supporting connective tissue.
• Adipose. Adipose is another type of supporting connective tissue that provides cushions and stores excess energy and fat.
• Blood.
• Hemapoetic/Lymphatic.
• Elastic.
• Fibrous.

Connective tissues are classified into four classes: BLOOD, BONE, CARTILAGE, CONNECTIVE TISSUE PROPER.

4.3B: Types of Connective Tissue

• Areolar Connective Tissue.
• Adipose Tissue or Body Fat.
• Reticular Connective Tissue.
• Dense Regular Connective Tissue.
• Dense Irregular Tissue.
• Elastic Connective Tissue.
• Cartilage.
• Elastic Cartilage.

All connective tissue consists of three main components: fibers (elastic and collagen fibers), ground substance and cells. Not all authorities include blood or lymph as connective tissue because they lack the fiber component. All are immersed in the body water.

The major types of connective tissue are connective tissue proper, supportive tissue, and fluid tissue. Loose connective tissue proper includes adipose tissue, areolar tissue, and reticular tissue.

Blood is considered a connective tissue because it has a matrix. The living cell types are red blood cells, also called erythrocytes, and white blood cells, also called leukocytes. Erythrocytes (red blood cells), the predominant cell type, are involved in the transport of oxygen and carbon dioxide.

Blood is classified as a connective tissue and consists of two main components:

• Plasma, which is a clear extracellular fluid.
• Formed elements, which are made up of the blood cells and platelets.

Blood tissues are found inside the blood vessels (arteries, arterioles, capillaries, venules and veins – see the systemic circulation for further details about the path the blood follows and the names of specific blood vessels) and also within the chambers of the heart.

Blood Provides the Body’s Cells with Oxygen and Removes Carbon Dioxide. Blood absorbs oxygen from air in the lungs. It transports the oxygen to cells throughout the body, and it removes waste carbon dioxide from the cells.

Blood is both a tissue and a fluid. It is a tissue because it is a collection of similar specialized cells that serve particular functions. These cells are suspended in a liquid matrix (plasma), which makes the blood a fluid.