General Biology lab Lab 7&8 Animal Tissues

A tissue : Is aggregation of cells, perform the same function, and is bound together by a certain substance known as the Intercellular substances (matrix). Histology : the science concerned with the study of tissue.

There are four types of tissue. 1.Epithelial Tissue (covering) 2.Connective Tissue (support) 3.Muscular Tissue (movement) 4.Nervous Tissue (control)

Epithelial Tissue They Include Tissue that cover external surfaces, line internal organs or form parenchyma of glands. It has the following characteristics: –They are situated on basement membrane –Minimum Extracellular substance (matrix) –No supply of blood vessel or lymphatic but only nerves. –They arise from three germ layer, ectoderm, endoderm, mesoderm

Classification of Epithelial Tissues According To Their Structure They Are Classified : 1.Simple Epithelium E.g. columnar A.Non cilliated found in small intestine B.Cilliated found in bronchioles of lungs 2.Stratified epithelium (compound) –E.g. Transitional stratified epithelial, found in urinary bladder

Connective Tissue –a kind of tissue that connects, supports, or surrounds other tissues and organs. They have the following characteristics : –Develop from the mesoderm –Unlike the epithelium, they contain wide intracellular substances. –Supply with blood vessels, nerves and fiber.

Function : 1.Support and connect different type of organ 2.Surround vessel and nerves 3.Fiber provide flexibility and resistance 4.Act as mean of transporting for nutrition and for removal of metabolites 5.Act as immunological barrier by aid phagocytic and defense cell 6.Mast cell found in this tissue produce heparin and histamine 7.Fat cell in the tissue act as food reservoir, shock absorbent and for body temperature maintenance

Classification of connective tissue 1.Connective tissue proper 2.Skeletal connective tissue 3.Vascular connective tissue

Connective tissue proper 1.Areolar connective tissue : –Most widely distributed connective tissue. –Soft, pliable tissue that cushions and protects the body’s organs it wraps. –Holds internal organs together and in their proper position. –Under microscope: matrix appears as empty space.

2.Adipose connective tissue –Locate beneath the skin and around internal organ. –The nuclei appear as small disks on the periphery of cells. –Functions to insulate the body, protect organs, and fuel storage.

Skeletal connective tissue 1.Cartilage –a flexible connective tissue found in many areas in the bodies of humans and other animals, such as the ear, the nose, the elbow, the knee, the ankle. – It is not as hard and rigid as bone but is stiffer and less flexible than muscle. Function : –reduces friction in the joint with movement. –holds some bones together.

2.Bone –It cover by periosteum سمحاق. –Bone marrow is the site of red blood production. Function of bone : –Support –Movement –Reservoir of Ca –Protection of organs ( brain, heart )