Biology

Human Excretion and Kidney Physiology

1,152 Questions

Human excretion and kidney physiology questions test your understanding of the excretory system, including the role of renal tubules and glomerular filtration. You will also find topics on urine formation, body water absorption, and excretory products. This section is vital for medical and general science exam preparation.

Glomerular filtrationRenal tubule absorptionExcretory productsRole of sodium ionsHuman excretory system

Human Excretion and Kidney Physiology Questions

Multiple choice

What are the waste products of kidneys?

  1. Salts, water and carbon dioxide

  2. Urea and water

  3. Urea, water and salts

  4. Urea and salts
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The correct option is (3). Urea, water and salts are the waste products of kidneys.

Multiple choice

Which of the following statements is incorrect?

  1. Respiratory waste products are formed as a result of oxidation of glucose.

  2. The excretory processes play an important role in the homeostasis in the body.

  3. Salts are mainly excreted through sweat glands of our skin.

  4. Accumulation of urea in the body may cause death.

  5. A large amount of bile pigments is excreted through faeces.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Salts are mainly excreted by kidneys through urine.

Multiple choice

Ornithine cycle occurs in

  1. liver

  2. urinary bladder

  3. kidneys

  4. lungs
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Urea is the major end product of nitrogen metabolism in humans and mammals. Ammonia, the product of oxidative deamination reactions, is toxic in even small amounts, and must be removed from the body. The urea cycle or the ornithine cycle describes the conversion reactions of ammonia into urea. Since these reactions occur in the liver, the urea is then transported to the kidneys, where it is excreted.

Multiple choice

The urge to urinate is controlled with the help of

  1. long collecting duct

  2. glomerulus

  3. muscular urinary bladder

  4. urethra

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The urinary bladder is muscular, so it is under nervous control. As a result, we can usually control the urge to urinate.

Multiple choice

The chloride ions from the glomerular filtrate are reabsorbed through

  1. passive reabsorption

  2. active transport

  3. osmoregulation

  4. diffusion
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Diffusion is the tendency of molecules  to spread into an available space. This tendency is a result of the intrinsic thermal energy (heat) found in all molecules, at temperatures above absolute zero. Without other outside forces at work, substances will move/diffuse from a more concentrated environment to a less concentrated environment. The chloride ions from the glomerular filtrate are reabsorbed through diffusion.

Multiple choice

Which of the following statements is incorrect?

  1. Dialysis is a process of removal of nitrogenous waste from the body.

  2. Dialysing fluid has the same osmotic blood pressure as blood.

  3. Waste products from the blood pass into dialysing fluid by diffusing.

  4. Reabsorption of glucose and salt takes place from the dialy<font size="2">s</font>ing fluid.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Artificial kidneys contain a number of tubes with a semi-permeable lining, suspended in a tank filled with dialysing fluid. This fluid has the same osmotic pressure as blood, except that it is devoid of nitrogenous wastes.

Multiple choice

Water is not reabsorbed in

  1. proximal convoluted tubule

  2. descending limb of loop of Henle

  3. ascending limb of loop of Henle

  4. distal convoluted tubule
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Water is not reabsorbed in ascending limb of loop of Henle. It is impermeable to water.

Multiple choice

Match the following:

Organs Uses
a. Lung 1. It is used for removal of excess sugar by converting it into glycogen for further use.
b. Skin 2. It is used for excretion of carbon dioxide and water vapour produced during respiration.
c. Liver 3. It is used for excretion of urea, salt and excess water by means of sweat glands.

  1. a - 2, b - 1, c - 3

  2. a - 1, b - 2, c - 3

  3. a - 3, b - 2, c - 1

  4. a - 2, b - 3, c - 1

  5. a - 1, b - 3, c - 2
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This is the correct option. Lung is used for excretion of carbon dioxide and water vapour produced during respiration. Skin is used for excretion of urea, salt and excess water by means of sweat glands. Liver is used for removal of excess sugar by converting it into glycogen for further use.

Multiple choice

Which of the following statements regarding the physiology of loop of Henle is INCORRECT?

  1. The descending loop of Henle receives hypotonic fluid from the proximal convoluted tubule (PCT).

  2. Substances reabsorbed in the PCT include urea, water, potassium, etc.

  3. The interstitium of the kidney increases in osmolarity outside.

  4. In the ascending portion, the loop becomes impermeable to water.

  5. Flow of the fluid through the entire loop of Henle is considered slow.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The descending loop of Henle receives isotonic fluid from the proximal convoluted tubule (PCT). The fluid is isotonic because as ions are reabsorbed by the gradient time system, water is also reabsorbed, maintaining the osmolarity of the fluid in the PCT.

Multiple choice

Ammonia is converted into urea by the

  1. kidney

  2. liver

  3. spleen

  4. pancreas
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Urea or carbamide is an organic compound. Urea serves an important role in the metabolism of nitrogen-containing compounds by animals and is the main nitrogen-containing substance in the urine of mammals. It is solid, colourless and odourless, and ammonia is converted into urea by the liver.