Question

Transitional epithelium is found in
A. Larynx
B. Vein
C. Kidney
D. Ureter and renal pelvis

Answer 1

Hint: Transitional epithelium is a stratified tissue in which the cells have a round shape when the organ it lines is not stretched out or distended. When tissues are stretched the cells become flat.

Complete answer:
Larynx is lined by the pseudo stratified ciliated columnar epithelium, with a transition zone of the stratified columnar epithelium.
The surface of excretory ducts in glands and some of the organs in the body are lined by the simple cuboidal epithelium. Also it composes some of kidney tubules in the cortex of kidney, and creates the covering of the ovary.
The simple squamous epithelium lines the vein and lining of blood vessels is called endothelium.
Transitional epithelium is a type of stratified epithelium with multiple layers of cells. According to the function of the organ, the shape of the cell changes. Since the epithelium appears round or cubical when in a relaxed state epithelium, it has a varying appearance, except the apical layer which seems to be flattened when stretched. Since, the epithelium is almost limited to the urinary system; it is also termed as urothelium. Urothelium is found in ureter and the superior urethra, renal pelvis, urinary bladder and gland ducts of the prostate.
These cells stretch to accommodate liquid volume fluctuation in an organ. In females, the distal part of urethra becomes non-keratinized stratified squamous epithelium. The part that lines the bottom of the tissue is known as the basement membrane. Transitional epithelium functions as a barrier between the lumen or the inside hollow space of the tract that it lines and the bloodstream. In order to help attain this, the cells of transitional epithelium are connected by virtually impenetrable junctions or tight junctions that seal together to the cellular membranes of neighboring cells. This barrier prevents absorption of pathogens and toxic wastes again to the bloodstream.

Hence, the correct answer is option (D).

Note: Due to its location of epithelial cells in the urinary bladder and ureters, one of the main functions of this tissue is to be an effective permeability barrier, impenetrable to water and most small molecules.