Which of the following is the correct pathway for passage of urine in humans?

Options

A. Collecting tubule `to` Ureter `to` Bladder `to` Urethra
B. Renal vein `to` Renal ureter `to` Bladder `to` Urethra
C. Pelvis `to` Medulla` to` Bladder `to `Urethra
D. Cortex `to` Medulla `to` Bladder `to` Ureter

Answer

To determine the correct pathway for the passage of urine in humans, we can break down the process into a series of steps:

### Step-by-Step Solution:

1. **Formation of Urine**: Urine is produced in the kidneys through the filtration of blood in the nephrons, which are the functional units of the kidney.

2. **Collecting Tubules**: Once urine is formed, it travels from the nephrons into the collecting tubules. The collecting tubules are responsible for collecting urine from multiple nephrons.

3. **Calices of the Kidney**: The collecting tubules lead to the renal calices (or calyces), which are cup-like structures in the kidney that collect urine from the collecting tubules.

4. **Renal Pelvis**: The renal calices converge to form the renal pelvis, which is the funnel-shaped structure that collects urine before it moves to the ureter.

5. **Ureter**: From the renal pelvis, urine flows into the ureter. Each kidney has its own ureter, which transports urine from the kidney to the bladder.

6. **Bladder**: The ureters lead to the urinary bladder, which is a muscular sac that stores urine until it is ready to be excreted.

7. **Urethra**: When the bladder is full, nerve signals trigger the bladder muscles to contract, pushing urine into the urethra, which is the tube that carries urine out of the body.

8. **Excretion**: Finally, urine is expelled from the body through the urethra during the process of urination.

### Correct Pathway:
The correct pathway for the passage of urine in humans is:
**Collecting Tubules → Renal Calices → Renal Pelvis → Ureter → Bladder → Urethra**