Connective tissue : Connective tissue is a fundamental animal tissue that has scattered living cells embedded in matrix. The matrix and cells are different in different connective tissues. 

Based on the nature of matrix, connective tissue is divided into three types: 

(i) Connective tissue proper : It is type of connective tissue that has jelly-like matrix and three types of fibers: white collagen, yellow elastin and reticular fibres. The living cells present may include fibroblasts, mast cells, plasma cells, Macrophages and lymphocytes. 

It is of two types : 

(a) Loose connective tissue : In this, cells (fibroblasts, macrophages, mast cells etc) and fibres are loosely arranged in a semi-fluid matrix. It has fewer fibres and more of matrix. 

It is of two types: Areolar tissue and Adipose tissue.

1. Areolar Tissue : It is the most widely spread connective tissue in the body. The non-living intercellular matrix contains irregular shaped cells and two kinds of fibres. Location : Areolar tissues are found inside organs, around blood vessels, muscles and nerve. It also occurs below sub-cutaneous tissue and structures like muscles and skin. 

2. Adipose Tissue : It is a type of connective tissue that is specialized to store fat called adipose cells. The fats are stored inside cells called adipocytes. Adipocytes are large cells with one or more globules of fat and peripheral cytoplasm with nucleus at one end.

Location : The tissue is found below the skin, around internal organs and inside yellow bone marrow. 

(b) Dense connective tissues: In this, fibres and fibroblasts are compactly packed. It has more of fibres and less amount of matrix. 

It is of two types: 

1. Dense regular connective tissues : They show regular pattern of fibres. Collagen fibres are present in rows between many parallel bundles of fibres. e.g., tendons and ligaments. 

• Tendon : Tendon is a tough, non-fibrous, dense. white fibrous connective tissue. It has great strength but limited flexibility. 

Function: It joins a skeletal muscle to a bone, thereby helping the bone to move on contraction and relaxation of the muscle. 

• Ligament: Ligament is a dense yellow fibrous connective tissue. It has considerable strength and high elasticity. 

Function: Ligament binds a bone with another bone.

2. Dense irregular connective tissues : They have irregular pattern of fibres. It has fibroblasts and many fibres (mostly collagen) that are oriented differently. This tissue is present in skin.