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

Which of the following statements regarding water balance by the kidney is CORRECT?

  1. Aquaporin is the main hormone regulating water reabsorption.

  2. The key hormone regulating water reabsorption is secreted from the anterior pituitary gland.

  3. The vasa recta has the same structure as the Loop of Henle.

  4. There are osmoreceptors in the hypothalamus.

  5. There is no limit to how much the body can concentrate the urine.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

There are osmoreceptors in the hypothalamus, which 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 statements characterises the renal blood flow in humans?

  1. The efferent arterioles deliver blood to the glomerulus.

  2. Vasa recta receive their blood supply from the afferent arterioles.

  3. Vasoconstriction of afferent arterioles increases glomerular filtration.

  4. Vasoconstriction of the efferent arterioles increases glomerular filtration.

  5. Vasoconstriction reduces the resistance to flow in a blood vessel.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

If there is vasoconstriction of the efferent arteriole, the pressure upstream the constriction in the glomerulus is increased and so more filtration occurs.

Multiple choice

Which of the following does not cause vasoconstriction in the kidneys?

  1. Angiotensin II

  2. Vasopressin

  3. Epinephrine

  4. Non-steroidal anti-inflammatory drugs

  5. Prostaglandins
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Non-steroidal anti-inflammatory drugs block prostaglandin synthesis and so remove this tonic dilatation. The result is renal vasoconstriction. Prostaglandins are powerful vasodilators and there is a normal tonic level of vasodilation in the renal blood vessels, which is caused by prostaglandins.

Multiple choice

Which of the following statements is true regarding sodium ions absorption in the kidneys?

  1. The concentration of sodium ions is generally higher inside the cells than outside .

  2. The amount of sodium in the initial filtrate is much less than that in the plasma.

  3. Most sodium is reabsorbed in the distal tubule.

  4. There is no active transport of sodium.

  5. The diuretic drug furosemide blocks the Na-K-2Cl channel in the loop of Henle.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Diuretics such as furosemide inhibits sodium reabsorption in the loop of Henle by blocking the Na-K-2Cl channel in the loop of Henle. Drugs such as the thiazides oppose sodium reabsorption in the distal tubule.

Multiple choice

After the investigation, doctor told Amit that he was suffering from renal artery stenosis. Which of the following tests must have been done by the doctor?

  1. Ultrasound scanning

  2. Measurement of the creatinine clearance

  3. Measurement of protein loss in the urine

  4. Renal angiography

  5. Renal biopsy
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Renal angiography involves the injection of a radio opaque dye into the renal vessels while x-ray images are taken of the vessels. Using this approach, it is possible to identify stenoses or narrowings in the renal arteries.

Multiple choice

Potassium secretion occurs only in______________.

  1. principal cells of the collecting duct

  2. glomerulus

  3. loop of Henle

  4. the intercalated cells of collecting duct

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

Potassium secretion occurs only from the principal cells of the collecting duct. It is this potassium secretion, which is used to control potassium excretion.

Multiple choice

Regarding the clinical assessment of patients with suspected renal disease, which of the following statements is true?

  1. Peripheral edema suggests volume depletion.

  2. Bruits heard over the renal arteries suggest renal artery stenosis.

  3. Dipstick testing of urine is an ineffective technique.

  4. Measuring blood pressure is unnecessary.

  5. A drug history can be safely omitted.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Renal artery stenosis describes narrowings of the renal arteries.When there is such a narrowing, turbulent flow through the narrowing can produce a noise known as a bruit. This is important because the narrowing can reduce the blood supply to the kidney and thus can damage the kidney.

Multiple choice

Which of the following statements is true regarding potassium ion in the kidneys?

  1. Potassium is the major extracellular ion.

  2. Within cells, the concentration of potassium is lower than that of sodium.

  3. Potassium excretion is regulated by altering potassium secretion.

  4. The 3Na+/2K+ ATPase pumps potassium out of cells.

  5. Specialised cells have potassium channels.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Potassium is freely filtered and then most of the filtered potassium is reabsorbed. Potassium excretion is then controlled by the secretion of potassium by the principal cells in the collecting ducts. 

Multiple choice

Which of the following transporter molecules exchanges sodium for hydrogen ions in the proximal tubule of the kidneys?

  1. Na-K--2Cl

  2. ROMK

  3. 3Na+/2K+ ATPase

  4. NHE 3

  5. ENaC
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The NHE 3 is a counter transporter that exchanges sodium ions in the tubular fluid for hydrogen ions from the cell. This is a passive process, which like sodium reabsorption in most other tubular cells, occurs along the sodium concentration gradient which has been created by the 3Na+/2K+ ATPase.

Multiple choice

Which of the following statements is true regarding acid base regulation in the body?

  1. Overall human metabolism results in acid production .

  2. Buffers present in kidneys must be strong acids or bases.

  3. Carbon dioxide directly raises the pH of body fluids.

  4. The pH of a buffer solution is always 7.

  5. A rise in the plasma level of bicarbonate ions lowers the pH of plasma.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Overall the body is a net producer of acid, and a major function of the kidney is to excrete this acid load.

Multiple choice

Which of the following statements does not characterise the renal tubules?

  1. The major changes in tubular fluid composition are fabricated in the distal tubules.

  2. The proximal tubules consequentially keeps the concentration of urine same.

  3. A part of the loop of Henle is permeable to water.

  4. Vasa recta are the only blood supply to renal medulla of the kidneys.

  5. The walls of the tubules are made up of epithelial cells.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The major transitions to tubular fluid are made in the proximal tubules, where there is considerable reabsorption of the bulk of solutes and water. The distal tubules also carry out reabsorption, but on a smaller scale.

Multiple choice

Considering the glomerular filtration, which among the following statements is true?

  1. The main site of glomerular filtration is the loop of Henle.

  2. Bowman's capsule surrounds the perinephric fat.

  3. The filtration barrier accomodates two layers of cells.

  4. Constriction of the afferent arterioles enhances filtration.

  5. Glomerular filtration of molecules is independent of their size and charge.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The filtration barrier is made up of two layers of cells and the basement membrane that lies between them. These two layers of cells in the filtration barrier are the endothelial cells of the glomerular capillaries and the epithelial cells of Bowman's capsule .

Multiple choice

Which of the following statements regarding human kidney is INCORRECT?

  1. If a substance is neither reabsorbed nor secreted in the tubules, the amount filtered in the glomeruli is equal to the amount excreted in the urine.

  2. In severe untreated renal failure, plasma creatinine levels fall.

  3. Nuclear imaging can provide information about renal blood flow and function.

  4. Normal urine does not contain free myoglobin.

  5. Bleeding is a potential complication of renal biopsy.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Creatinine is removed from plasma by the kidney. So, if the kidney is not functioning properly, the level in plasma will rise.

Multiple choice

Which of the following statements concerning renal development is INCORRECT?

  1. There are three kidney structures that are formed at different times during development.

  2. The final adult kidney originates from the pronephros.

  3. The ureteric bud leads to the formation of draining system.

  4. The capillaries invaginate the tubules to form glomeruli.

  5. The final adult kidney rises up the body during normal development.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

It is not the correct statement as it is the metanephros, which goes on to become the adult kidney.

Multiple choice

Regarding the developmental anomalies of the renal system, which of the following statements is correct?

  1. The failure of the development of ureteric bud causes hypospadias.

  2. Horseshoe kidneys are formed when the pronephros fails to regress.

  3. Adult kidneys can have only one renal artery.

  4. Early splitting of the ureteric bud can result in one kidney having two ureters.

  5. The ureteric bud forms the glans penis.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The ureteric bud forms the collecting system. If it splits before it enters the kidney, the result is that the kidney will have two ureters.