How is the tissue found in renal pelvis modified to carry out its function?
The tissue found in the renal pelvis, known as the transitional epithelium, undergoes specific modifications to carry out its essential functions related to urine transport and protection. Here are the key modifications of the transitional epithelium in the renal pelvis:
1. Multiple Layers: The transitional epithelium consists of multiple layers of cells, allowing it to accommodate the changes in volume and pressure within the renal pelvis. As urine flows into the renal pelvis from the ureters, the epithelium can stretch and expand without compromising its integrity.
2. Cuboidal to Columnar Cells: The cells of the transitional epithelium can change their shape depending on the level of distension in the renal pelvis. When the pelvis is relaxed, the cells appear cuboidal. However, as the volume of urine increases, the cells elongate and become columnar, providing a smooth lining for urine transport.
3. Specialized Cell Junctions: The cells of the transitional epithelium are tightly connected by specialized cell junctions, including tight junctions and desmosomes. These junctions prevent the leakage of urine between the cells and maintain the integrity of the epithelium, ensuring efficient urine transport.
4. Glycocalyx Layer: The surface of the transitional epithelium is covered by a layer of glycocalyx, a network of carbohydrates and glycoproteins. This glycocalyx layer acts as a protective barrier, preventing the adherence of bacteria and other particles to the epithelium and reducing the risk of infection.
5. Uroplakins: The umbrella cells, which are the outermost layer of the transitional epithelium, contain unique proteins called uroplakins. Uroplakins form a protective layer that resists the permeation of harmful substances and ions, contributing to the barrier function of the epithelium.
Overall, the modifications of the transitional epithelium in the renal pelvis enable it to adapt to changing luminal conditions, provide a low-resistance pathway for urine transport, and protect the underlying tissues from potential insults, ensuring the efficient elimination of urine from the kidneys.