In our last article we discussed four major types of tissues in animals and then we discussed epithelial tissue in detail. Today we will discuss about connective tissue, the second important tissue in animal body.

Connective tissue:

Connective tissues are distributed throughout an extracellular matrix. This matrix frequently contains fibers that are embedded in a ground substance called lumen. The nature of this extracellular material determines the functional properties of the various connective tissuesa large extent.

Types of connective tissue:

There are two types of connective tissue.

Ø  Loose connective tissue

Ø  Fibrous connective tissue

Loose connective:

Loose connective tissue consists of strong, flexible fibers of the protein collagen which are interwoven with fine, elastic and reticular fibers giving loose connective tissue. This makes it an excellent binding tissue (binding the skin to underlying muscle tissue).

Fibrous connective tissue:

The collagen fibers are densely packed and may lie parallel to one another, creating very strong cords, such as tendons and ligaments.

Ø  Tendons connect muscles to bones.

Ø  Ligaments connect the bones to bones.

Functions of connective tissue:

Connective tissue performs many functions but most importantly they support and connect other tissue. Protection is another important function connective tissue performs in the form of fibrous capsules and bones that protect delicate organs. Specialized cells in the tissue defend the body from microorganisms that enter the body. Transport of fluid, nutrients, waste materials and chemical messengers is ensured by connective tissue. Surplus energy contribute to the thermal insulation is in the form of adipose tissue cells.

Adipose tissue:

Adipose tissue is a type of loose connective tissue that consists of large cells that store lipids. A large number of cells accumulate to form fat.  White adipose tissue can be found protecting the kidneys and cushioning the back of eyes. The adipose tissue common in infants is brown adipose tissue which is called “baby fat”

Cartilage:

Cartilage is hard yet flexible tissue that supports the structures as the outer ear and forms the entire skeleton of such animals as sharks and rays.

Cells present in the cartilage are called chondrocytes which lie within a space called lacunae. The strength of cartilage is due to collagen fibers with matrix. elasticity.

The three main types of cartilage are hyaline cartilage, fibro cartilage and elastic cartilage.

Ø  Hyaline cartilage is found in the rib cage and nose and also covers bones.

Ø  Fibrous cartilage is example of knee and jaw joints.

Ø  Elastic cartilage contains elastic fibers. The external ear contains elastic fibers.

Bone:

Bone is the hardest connective tissue. Bone provides protection to internal organs and supports the body.

Bone cells are called osteocytes also lie within the lacunae, but the matrix around them is heavily impregnated with calcium carbonate, making this kind of tissue hardest of all.

Ø  Function of bone is support and protection.

Blood:

It is a connective tissue in which fluid called plasma suspends specialized red and white cells plus platelets. The cells in the blood transport oxygen and some carbon dioxide. Nutrients, salts and wastes are dissolved in the blood.