Types of loose connective tissue
Structure: It takes the form of fine threads crossing each other in every direction leaving small spaces called areolae. It consists of ground substance, the matrix, white and yellow fibres and cells like fibroblasts, mast cells, macrophages (= histocytes or clasmatocytes), lymphocytes, plasma cells, mesenchyme cells, chromatophores. Fat cells can be seen in small groups.
Location: It is present under the skin as subcutaneous tissue in between and around muscles, nerves and blood vessels in submucosa of gastrointestinal tract and respiratory tract, in the bone marrow, between the lobes and lobules of compound glands and in mesenteries and omenta.
Function: The primary function of areolar tissue is to bind parts together. Other functions are to provide strength, elasticity, support to the parts where this tissue is present. It also provides rapid diffusion of materials and migration of wandering cells towards areas of infection and repair.
Structure: It is a fat storing connective tissue. The adipose tissue consists of several spherical or oval adipose cells (= adipocytes or fat cells). Each adipose cell contains fat globules, due to which the nucleus and the cytoplasm are displaced to the periphery. These cells are often called signet ring cells.
Location: The adipose tissues are found in the subcutaneous tissue, around the heart, kidneys, eyeballs, mesenteries and omenta, where fat is stored.
Function: The adipose tissue is chiefly a food reserve or ‘fat depot’ for storage. The subcutaneous fat prevents heat loss from the body and also rounds off the body contour sheet. It forms a shock-absorbing cushion around the eye balls and kidneys.
Structure: This tissue consists of star-shaped reticular cells whose protoplasmic processes join to form a cellular network. The reticular fibres are present on the reticular cells. They are composed of a protein called reticulin. Matrix and some other cells such as macrophages, lymphocytes and adipose cells are also present.
Location: Reticular connective tissue is present in the liver, spleen, lymph nodes, thymus, tonsils, bone marrow and lamina propria of the gut wall.
Function: The reticular connective tissue is especially adapted to provide strength and support and it forms the supporting framework (stroma) of many organs. It also helps to bind together the cells of smooth muscles. The reticular cells are phagocytic and form defence mechanism of the body.