Question

32e. State which portion of 3a touches the basement membrane. 34a. Define regeneration/renewal and explain the functional significance of renewal to epithelial tissue. 35a. Explain the difference between simple and stratified epithelium in terms of structure and function. 35b. Explain the difference between simple squamous and simple cuboidal/columnar epithelium in terms of structure and function. 36a. Explain the difference between keratinized versus non-keratinized stratified squamous in terms of structure and function.

Answer 1

34 a. Regeneration: it refers to the renewal and growth of any cell by repair or replacement of cells and make the tissue resilient to environmental damage.

Functional significance- renewal in the epithelial tissue makes it resilient to any kind of stress or injury. Whenever cells of epithelial tissue are damaged due to any injury, they are repaired or replaced and thus the tissue becomes normal.

35 a. structure- simple epithelium consists of only one layer of cells wheres stratified epithelium consists of more than one layers on top of the other.

function-simple epithelium is present in the lining of glands and ducts and are used for secretion or where absorption is required. It is also present where exchange of materials has to take place. Stratified epithelium is present where there is wear and tear.For eg. skin and protects from mechanical injuries.

35 b. Structure- simple squamous epithelium consists of flat cells. Simple cuboidal epithelium consists of cube like cells with almost same size and shape. Simple columnar epithelium consists of elongated or tall column-like cells with nucleus at their base.

Function - simple squamous is present to facilitate exchange of gas or other material. Eg in alveoli of lungs and capillaries. Simple columnar/ cuboidal cells perform the functions of secretion and absorption.

36 a. Structure- keratinized stratified squamous epithelium consists of several layers of squamous cells with the topmost layer containing keratin. Keratin is a protein. These cells are dead and are devoid of nucleus and other organelles. Non-keratinized epithelium does not have this layer of keratin cells.

Function-keratinized epithelium protects the tissue from dehydration and desiccation and also ,makes it waterproof. It also protects from abression. It is present in skin.Non- keratinized epithelium is present everywhere else in the body.