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

Potassium secretion occurs only in the

  1. glomerulus

  2. principal cells of collecting duct

  3. loop of Henle

  4. intercalated cells of collecting duct

  5. proximal tubule
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Potassium secretion occurs only from the principal cells of collecting duct and it is this potassium secretion that is used to control potassium.

Multiple choice

Which of the following statements about human kidneys is true?

  1. The renal cortex contains all the glomeruli.

  2. Urethra is the link between kidneys and bladder.

  3. The renal veins drain directly into superior vena cava.

  4. The left kidney lies lower than the right kidney.

  5. The renal cortex lies inside the medulla.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

All the glomeruli are in the renal cortex. The loop of Henle dips into the medulla and the collecting ducts drain into the renal pelvis by passing through the medulla.

Multiple choice

Which of the following statements regarding water balance and kidneys is correct?

  1. There are osmoreceptors in the hypothalamus.

  2. There is no limit as to how much urine the body can concentrate.

  3. The vasa recta is the same structure as the loop of Henle.

  4. Aquaporin is the main hormone regulating water reabsorption.

  5. The key hormone regulating water reabsorption is secreted from the anterior pituitary gland.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

There are osmoreceptors in the hypothalamus that detect an increase in plasma osmolality. In response to input from these receptors and other stimuli, cells in the posterior pituitary gland release ADH.

Multiple choice

Which of the following is not a characteristic of metabolic alkalosis by the nephrons?

  1. Panic attacks cause a transient respiratory alkalosis.

  2. Rise in plasma carbon dioxide level causes a respiratory acidosis.

  3. A normal plasma chloride concentration is necessary for normal renal bicarbonate excretion.

  4. ADH excess causes excess renal bicarbonate reabsorption.

  5. In a metabolic alkalosis, plasma bicarbonate is raised.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Aldosterone excess causes excess renal bicarbonate reabsorption.

Multiple choice

Post-streptococcal glomerulonephritis may develop a week or two after recovery from a streptococcal throat infection. Which of the following statements is true about acute post-streptococcal glomerulonephritis?

  1. It only occurs following upper respiratory tract infection.

  2. It typically follows within 5 days of streptococcal infection.

  3. The anti-DNAse B titre is a better indicator of streptococcal skin sepsis than the ASO titre.

  4. It is consistently associated with a normal C3 level in the early phase.

  5. Only 10% children recover completely after the clinical course.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Cholesterol and lipids in skin modify the antigenicity of streptolysin O and suppress the ASO antibody response, but not the anti-DNAse B antibody titre.

Multiple choice

Which of the following statements is incorrect regarding renal tubular acidosis?

  1. Hypoaldosteronism can cause renal tubular acidosis.

  2. Distal renal tubular acidosis is associated with multi-system disorders.

  3. Proximal renal tubular acidosis is associated with other tubular disorders.

  4. It occurs when kidneys do not reabsorb potassium ions.

  5. Bicarbonate loss from the kidney causes acidosis.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Renal tubular acidosis occurs when kidneys do not adequately reabsorb bicarbonate.

Multiple choice

Paracetamol causes acute and chronic renal tubules failure. Which of the following statements is false regarding the renal tubules in kidneys?

  1. The walls of the tubules are made up of epithelial cells.

  2. The vasa recta are blood vessels.

  3. Part of the loop of Henle is permeable to water.

  4. The proximal tubules substantially increase the concentration of urine.

  5. The major changes in tubular fluid composition are made in the proximal tubules.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The osmolality of filtered fluid entering the proximal tubule from the glomerulus is essentially that of plasma from which it is produced. Reabsorption in the proximal tubule is iso-osmotic. It means that the osmolality of the tubular fluid does not change because solutes and water is removed together in the same ratio at which they are present in the tubules. For this reason, the concentration of urine (i.e. its osmolality) in the proximal tubule is not altered.

Multiple choice

Hypernatremia is defined by an elevated sodium level in blood. Which of the following is not associated with hypernatremia?

  1. A good response to treatment by fluid restriction

  2. Increased neurological irritability

  3. Inadequate urinary concentration

  4. Loss of body water

  5. A rise in plasma osmolality
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The basic problem is usually loss of water. It is treated with careful replacement of water. As with hyponatremia, it is important not to replace the loss too quickly. The cells make compensatory changes during hyperosmolar conditions and a sudden change can be dangerous as the cells do not have time to readjust back to normal. The best way to prevent this is to keep checking the plasma sodium to ensure that it is not changing too quickly.