Question

1. Transitional epithelium (depicts a section through the wall of the urinary bladder, the same structure seen on your slide)

a. In what sense(s) is this epithelium transitional?

This epithelium lines the urinary bladder. What sorts of observations would you have to make in order to determine that the state of the epithelium depends on the degree to which the wall of the urinary bladder is distended?

What changes in form of the epithelium occur as the urinary bladder wall becomes more distended?

Name a few other organs that become distended as part of their normal function. In general these organs are not lined by transitional epithelium. Suggest why a transitional epithelium might be appropriate for the inner wall of the urinary bladder but not appropriate for the inner wall of another organ that can become distended.

Answer 1

The transitional epithelial is called so in the sense that its cells can change their shape according to the distension in the organ containing it like urinary bladder. For example when there is large distension then the cells become flattened and when distension is less then they may become round cuboidal shaped.

The other organs that can become distended are gall bladder, stomach, prostatic urethra ,ureters etc.

A transitional epithelial is appropriate for inner wall of urinary bladder because this provides extreme permeability barrier , impenetrable to water and other solutes. The cells of this tissue are most resistant to the osmotic pressure changes. As the urine has hypertonic concentration than the surrounding transitiinal epithelium but still the cells are protected from dessication even when the bladder is fully distended.

Second it also allows the store of harmful excretory products like urea,,ammonia etc in the urinary bladder n protect the body from their harmful effects.