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 zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

Juxta glomerular cells of renal cortex synthesizes an enzyme called

  1. ADH

  2. Oxytocin

  3. Renin

  4. Urochrome
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When renal blood flow is reduced, juxtaglomerular cells in the kidneys convert the prorenin present in the blood into renin and secrete it directly into circulation. Plasma renin then carries out the conversion of angiotensinogen released by the liver to angiotensin I. Angiotensin I is subsequently converted to angiotensin II by the enzyme angiotensin-converting enzyme found in the lungs. Angiotensin II is a potent vasoactive peptide that causes blood vessels to constrict, resulting in increased blood pressure.

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

If there is a deficiency of ADH its effect would be

  1. The volume of urine will increase

  2. The volume of urine will decrease

  3. The pH of urine will change from 4.8 to 8

  4. Secretion of urochrome takes place
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

ADH targets nephrons in kidney to increase water reabsorption and thereby decreasing water content in urine. Inability of neurohypophysial system to produce ADH, causes excess urine production with resultant ion loss from blood. This condition is known as diabetes insipidus (watery urine). 

Since ADH regulates the urine volume, not its pH. Urochrome is the yellow pigment, derived from breakdown of heme, which is deposited in blood and then is excreted by kidney with urine. 

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

Anti Diuretic Hormone(ADH) acts on the

  1. Collecting tubule of kidney

  2. Loop of Henle

  3. Collecting ducts of testes

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Osmoreceptors in the body are activated by changes in blood volume, body fluid volume and ionic concentration. An excessive loss of fluid from the body can activate these receptors, which stimulate the hypothalamus to release antidiuretic hormone (ADH) or vasopressin from the neurohypophysis. ADH facilitates water reabsorption from latter parts of the tubule (Distal convoluted tubule and Collecting duct), thereby preventing diuresis. An increase in body fluid volume can switch off the osmoreceptors and suppress the ADH release to complete the feedback. ADH mainly acts on collecting ducts of kidney and increase the water reabsorption in this part.

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

Water reabsorption in the distal parts of kidney tubules is regulated by

  1. STH

  2. TSH

  3. ADH

  4. MSH
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Vasopressin (ADH) is a peptide hormone, secreted from the posterior pituitary, increases water permeability of the kidney's collecting duct and distal convoluted tubule by inducing translocation of aquaporin-CD water channels in the collecting duct plasma membrane. Thus, increases the water absorption in the collecting duct and helps in water retaintion in the body.

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

The hormone involved in the active water reabsorption in renal tubules

  1. Anti-diuretic hormone

  2. Vasopressin

  3. Both A and B

  4. Adrenaline
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

ADH regulates the water balance in body by decreasing the excretion of free water from kidney (antidiuretic effect). It does so by increasing the permeability of ADH responsive cells in linings of distal convoluted tubules and collecting ducts of renal nephrons. 

ADH is also known as vasopressin owing to its role in vasoconstriction. 
Adrenaline is an emergency hormone secreted by adrenal medulla under emergency condition to prepare the body for flight or fight response. It decreases the ADH secretion and thereby causes increased frequency of micturition during stress conditions. 
Therefore, the correct answer is option C.

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

In a negative feedback system, a vascular organ of the brain monitors blood osmolarity and signals the release of ADH. When you eat salty food, your blood osmolarity rises above the set point. Predict what would happen next?

  1. ADH would not be released into bloodstream, large amounts of urine would be produced.

  2. ADH would be released into bloodstream and water would be reabsorbed.

  3. ADH would not be released into bloodstream and water would be reabsorbed.

  4. ADH would not be released, large amounts of urine would be produced.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Anti-diuretic hormone or the vasopressin is secreted by the hypothalamus and is stored and released by the posterior pituitary. This hormone is responsible for maintaining blood volume. When salty food is consumed, it increases the ions in the bloodstream and reduces the volume of the blood. The ADH will be released in this condition, that will directly act on the water reabsorbing channels in the collecting ducts of the nephrons. So, water will be reabsorbed from the filtrate and restored back to the blood. 

Hence, the correct answer is 'ADH would be released into bloodstream and water would be reabsorbed'

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

Assertion  :  The antidiuretic hormone increases the water permeability of distal convoluted tubule.

Reason    :    In absence of ADH, water re-absorption is considerably reduced


  1. If both the assertion and the reason are true and the reason is correct explanation of the assertion

  2. If both the assertion and reason are true but the reason is not correct explanation of the assertion

  3. If the assertion is true but the reason is false

  4. If both the assertion and reason are false

  5. If the assertion is false but reason is true
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

ADH is secreted by pituitary gland. It increases the water permeability of distal convoluted tubules and collecting tubules, hence, plays a significant role in water re-absorption. The absence of ADH will reduce water reabsorption which may lead to water diuresis or diabetes insipidus.

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

ADH takes part in

  1. Water retention in urine
  2. $Na^+$ reabsorption

  3. Reducing urea formation

  4. Absorption of water from urine
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
The reabsorption of water in the kidneys is under the control of ADH. It triggers the release of aldosterone which increases the concentration of sodium ions in the blood. The increased salt concentration in the blood increases the blood osmotic potential which further increases the reabsorption of water into the collecting tubule.
So, the correct answer is 'Absorption of water from urine'.
Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

Which ones regulate solute reabsorption during urine formation?

  1. ADH and angiotensin

  2. Angiotensin II and angiotensin I

  3. Norepinephrine and epinephrine

  4. Angiotensin II and aldosterone
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

 A fall in glomerular blood flow/glomerular blood pressure/GFR can activate the JG cells to release renin which converts angiotensinogen in blood to angiotensin I and further to angiotensin II. Angiotensin II, being a powerful vasoconstrictor, increases the glomerular blood pressure and thereby GFR. Angiotensin II also activates the adrenal cortex to release Aldosterone. Aldosterone causes reabsorption of Na+ and water from the distal parts of the tubule. This also leads to an increase in blood pressure and GFR. This complex mechanism is generally known as the Renin-Angiotensin mechanism. Hence Angiotensin  II and aldosterone regulate solute reabsorption during urine formation.

So, the correct answer is 'Option D'.

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

Excretion of dilute urine is due to

  1. More secretion of aldosterone

  2. Less secretion of vasopressin

  3. Less secretion of glucagon

  4. More secretion of insulin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Aldosterone is the hormone produced by the adrenal gland. Aldosterone balance sodium and potassium in our body. When Excess of aldosterone is produced by the adrenal gland causes the body to lose potassium and retain sodium. It leads to excretion of dilute urine.

So, the correct answer is 'More secretion of aldosterone'.

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

Identify the correct statement regarding urine formation.

  1. Counter-current mechanism works around glomerulus and PCT

  2. To prevent diuresis, ADH facilitates water reabsorption from the later parts of the tubule

  3. Maximum absorption of electrolytes occurs in Henles loop

  4. A decrease in blood pressure can increase glomerular filtration rate

  5. The collecting duct is impermeable to water and thus helps in diluting the urine
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The term diuresis refers to the excessive production of urine. When excess water is lost through urine the blood volume is decreased and its osmolarity is increased which stimulates the posterior pituitary to release ADH.ADH decreases the volume of urine by increasing the reabsorption in the later parts of the tubule and prevents diuresis. 

So, the correct answer is 'To prevent diuresis, ADH facilitates water reabsorption from the later parts of the tubule'.

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

ADH takes part in

  1. Reabsorption of $Na^+$

  2. Reabsorption of watera

  3. Tabular secretion of creatinine

  4. Tubular secretion of urea
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When excess water is lost through urine the blood volume is decreased and its osmolarity is increased which stimulates the posterior pituitary to release ADH. ADH decreases the volume of urine by increasing the reabsorption of water by kidneys and prevents diuresis. Thus ADH takes part in reabsorption of water.

So, the correct answer is 'Option B'.

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

Which is correct

  1. An increase in glomerular blood flow stimulates formation of angiotensin II

  2. During summer, when body loses a lot of water by evaporation, the release of ADH is suppressed

  3. When someone drinks a lot of water, ADH release is suppressed

  4. Exposure to cold temperature stimulates ADH release
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When excess water is lost through urine the blood volume is decreased and its osmolarity is increased which stimulates the posterior pituitary to release ADH.ADH decreases the volume of urine by increasing the reabsorption by kidneys and prevents diuresis. Hence when someone drinks a lot of water, ADH release is suppressed.

So, the correct answer is 'When someone drinks a lot of water, ADH release is suppressed'

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

Concentration of urine is controlled by

  1. ACTH

  2. MSH

  3. ADH

  4. Oxytocin
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The hormone ADH (vasopressin) is released from the neurohypophysis (posterior pituitary gland). ADH is synthesized by the hypothalamus and stored in the neurohypophysis. When blood volume is decreased or sodium concentration of blood is increased due to dehydration the ADH is released from the neurohypophysis. ADH causes retention of water by kidneys and maintains blood volume. Hence concentration of urine is controlled by ADH.
So, the correct answer is 'ADH'.
Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

Facultative absorption of water from primary urine is influenced by the hormone

  1. Androgens

  2. Epinephrine

  3. Vasopressin

  4. Thyroxine
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When excess water is lost through urine the blood volume is decreased and its osmolarity is increased which stimulates the posterior pituitary to release vasopressin. Vasopressin(ADH) decreases the volume of urine by increasing the facultative absorption of water by kidneys and prevents diuresis. Hence facultative absorption of water from primary urine is influenced by the hormone vasopressin.

So, the correct answer is 'Vasopressin'.