TISSUES Part2 Class 7 ICSE Animal Tissues Epithelial

TISSUES. Part-2 Class 7, ICSE.

Animal Tissues

Epithelial Tissue● ● Squamous Cuboidal Ciliated Columnar Muscular Tissue- Classification Of animal tissues ● ● ● Voluntary Cardiac Involuntary Nervous Tissue Connective Tissue● Connective tissue proper ● Skeletal tissue ● Fluid connective tissue

Epithelial Tissue

This tissue forms a continuous sheet of cells that covers the external surface of the body like skin as well as lines the cavities of internal organs like mouth (cheek cells), stomach, intestine and wind pipe. Structure: The cells are present end to end without intercellular spaces. They may be flat, irregularly shaped, cuboidal or in the shape of columns. Location: External surface of the body (skin), cavities of internal organs (mouth, stomach, intestine and wind pipe) Functions: ● It prevents the entry of germs and provides protection. ● It prevents the underlying cells from injury, entering of germs and from drying up

Types of Epithelial Tissue ● ● Squamous Epithelium Cuboidal Epithelium Columnar Epithelium Ciliated Epithelium

Squamous Epithelium ● It consists of a single layer of large, flat cells with central nuclei placed on a thin basement membrane ● They can be compared to the tiles on the floor. ● Example- The membranes lining the blood vessels and the inner lining of cheek.

Cuboidal Epithelium ● It is composed of a single layer of cuboidal cells placed on a basement membrane. ● The salivary gland the thyroid glands are internally lined by this epithelium.

Columnar Epithelium ● It is composed of tall, cylindrical cells, the height of each cell being greater than its width. ● The nuclei are oval and are usually found at the base of the cells. ● Inner lining of the intestines is an example.

Ciliated Epithelium ● Epithelial cells some-time bear hair-like cilia on their free surface. ● For example, the wind pipe or trachea is internally lined by ciliated epithelial cells.

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