Biology

Human Excretion and Kidney Physiology

1,215 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

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.

Multiple choice

The blood leaves the glomerulus through

  1. afferent arteriole

  2. efferent arteriole

  3. renal veins

  4. renal portal veins
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The blood leaves the glomerulus through efferent arteriole. They play an important role in maintaining the glomerular filtration rate despite fluctuations in blood pressure.

Multiple choice

Which of the following statements is/are correct?

a. Glomeruli filter the blood. b. Small molecules collect as filtrate in tubules. c. Bowman's capsule allows selective reabsorption of useful substances into blood capillaries.

  1. Only b

  2. Only a

  3. Only c

  4. Only b and c

  5. a, b and c
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A glomerulus is a network (as a tuft) of capillaries located at the beginning of a nephron in the kidney. It serves as the first stage in the filtering process of the blood carried out by the nephron in its formation of urine. The glomerulus is surrounded by a cup-like sac known as Bowman's capsule.

Multiple choice

Which of the following causes an increase in renal potassium excretion?

  1. Loop diuretics

  2. Aldosterone

  3. Spironolactone

  4. Increased urine flow rates

  5. Thiazide diuretics
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Spironolactone opposes the actions of aldosterone and so, has the opposite effect. It is an aldosterone receptor antagonist that causes the kidneys to remove water and sodium from the body, with reduced losses of potassium.

Multiple choice

Accumulation of nitrogenous waste products in the blood is an indication that the

  1. heart is not functioning

  2. kidneys are not functioning properly

  3. lungs are functioning

  4. liver is not functioning
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Accumulation of nitrogenous waste products in the blood is an indication that the kidneys are not functioning properly. Kidneys play a critical role not only in excreting waste products, but also in maintaining electrolyte and water balance. As kidney function declines, nitrogenous waste products, i.e. blood urea nitrogen (BUN), and creatinine accumulate.