Renal pelvis, renal cortex, renal medulla, renal papillae

Answer

To understand the terms renal pelvis, renal cortex, renal medulla, and renal papillae, we can break down each component related to the kidney's anatomy:

### Step-by-Step Solution:

1. **Renal Cortex**:
- The renal cortex is the outer region of the kidney.
- It is the part of the kidney that lies just beneath the renal capsule and surrounds the renal medulla.
- The cortex contains the renal corpuscles and the renal tubules (except for the loops of Henle), which are involved in the filtration of blood and the formation of urine.

2. **Renal Medulla**:
- The renal medulla is the inner region of the kidney.
- It consists of a series of structures known as renal pyramids, which are cone-shaped tissues that contain the nephrons' loops of Henle and collecting ducts.
- The renal medulla is responsible for the concentration of urine and the reabsorption of water and salts.

3. **Renal Pelvis**:
- The renal pelvis is a funnel-shaped structure that collects urine from the renal calyces and channels it into the ureter.
- It is formed by the convergence of two or three major calyces, which are the extensions of the renal pelvis that receive urine from the renal pyramids.

4. **Renal Papillae**:
- The renal papillae are the tips of the renal pyramids.
- Each renal papilla is the point where the urine formed in the renal pyramids drains into the minor calyx, which then leads to the major calyx and subsequently to the renal pelvis.
- The renal papillae serve as the exit points for urine from the pyramids into the collecting system of the kidney.

### Summary:
- **Renal Cortex**: Outer region of the kidney.
- **Renal Medulla**: Inner region containing renal pyramids.
- **Renal Pelvis**: Funnel-shaped structure collecting urine from the calyces.
- **Renal Papillae**: Tips of the renal pyramids where urine exits into the calyces.