Question

Stratified squamous epithelium, keratinized (depicts a section of skin, the same structure seen on your slide)

a. What is keratin? What properties are endowed to a tissue by abundant presence of keratin?

b. Describe the apparent shape of cells at the apical surface of the epithelium and the apparent shape of cells at the basal surface of the epithelium.

1. The example of stratified squamous epithelium (keratinized) you have is from skin. Why is this tissue well suited for this location?

2. Where in the tissue does the bulk of the keratin seem to be located?

3. If in your slide you could see skin cells undergoing mitosis, where in the epithelium would these cells be found? Why sorts of cells would be dividing? Why is cell proliferation important in this tissue?

4. Which of the other epithelia you have looked at would be likely to include cells comparable to those suggested in above? How might you recognize such cells if they happen to be present in a thin section you are examining?

Answer 1

a) Definition:

Keratin is a structural protein which is fibrous in nature. It is insoluble in water so that it is water proof. It is present in hair, horns, and claws and in the skin of human.

b) Properties of keratinized stratified squamous epithelium: This epithelium is composed of tightly packed dead cells filled with protein keratin in its outermost layer. And in its basement, there are so many connected tissues and blood vessels are present. The layer of keratin filled cells act as water proofing.

.1) Shape of the cells at the apical surface of the stratified squamous epithelium:

It is flattened in the outermost layer of the epithelium and consists of Microvilli which are small processing that project from epical surface of many epithelium cells

Shape of the cells at the Basal surface of epithelium is the attached surface of connective tissue

2) Cells on the surface of keratinized stratified squamous epithelium are very flat and dead.          They have no nucleus or organelles due to presence of keratin it makes our skin water proof. So this epithelium is suited for our skin.

3)The tissue which is dry in nature, keratin is present there. It is present in the cornifield layer of epidermis