Question 1

What is the primary structural and functional unit of the human kidney?

Accepted Answer

Nephron. The nephron is the basic functional unit responsible for filtering blood and forming urine. Each human kidney contains approximately one million of these microscopic structures. They consist of a renal corpuscle and a renal tubule.

Question 2

Which nitrogenous waste is primarily excreted by humans?

Accepted Answer

Urea. Humans are ureotelic organisms that primarily excrete urea as a metabolic byproduct. Urea is produced in the liver through the ornithine cycle to reduce toxicity. It is much less toxic than ammonia and requires less water for excretion.

Question 3

The cup-shaped structure at the beginning of a nephron is called the?

Accepted Answer

Bowman's capsule. Bowman's capsule surrounds the glomerulus and collects the initial filtrate from the blood. This structure performs the first step in the filtration of blood to form urine. It was named after the English surgeon and anatomist William Bowman.

Question 4

Which organ in the human body is responsible for the synthesis of urea?

Accepted Answer

Liver. The liver converts highly toxic ammonia into less toxic urea via the urea cycle. Once synthesized, urea is released into the bloodstream and later filtered out by the kidneys. This process is essential for nitrogen balance in the body.

Question 5

What is the name of the tube that carries urine from the kidney to the urinary bladder?

Accepted Answer

Ureter. The ureter is a muscular tube that uses peristaltic movements to transport urine. Each kidney has one ureter that connects it to the bladder. It prevents the backflow of urine through a functional valve-like mechanism.

Excretory System — Set 1