Question

(i) What are the structural and functional units of kidney?
(ii) Arrange the organs of the human excretory system in the correct order, based on the passage of urine.
Ureter, Urethra, Kidney, Urinary bladder.

Answer 1

(i) The nephrons are the structural and functional units of the kidney. Each kidney has about 1.2 million nephrons.

(ii) Urine is formed in the kidney. Urine flows into ureters from the kidney. Then the ureter transports urine into the urinary bladder. The urethra is a long tube which connects urinary bladder to the urinary meatus for removal of urine from the body. In males, urethra travels through the penis and meet the urethral meatus located at the tip of the penis. In females, urethra connects to the urethral meatus above the vagina. The urethra is also known as the urinary opening.

So the correct pathway or passage of urine is Kidney -->Ureter -->Urinary Bladder --> Urethra.