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

ADH helps in water elimination, making the urine hypotonic.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
ADH or antidiuretic hormone is produced in the hypothalamus and secreted from the neurohypophysis (posterior pituitary gland). ADH increases the reabsorption of water from the urine in the renal system back into the blood. Thus ADH conserves water in the kidneys and returns that fluid back to the general circulation. 
So the correct answer is 'False'.
Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

Urine of a human being suffering from diabetes insipidus is

  1. Tasteless and thick

  2. Sweet and thick

  3. Tasteless and watery

  4. Sweet and watery
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • Diabetes insipidus is a rare disorder that occurs when a person's kidneys pass an abnormally large volume of urine that is insipid dilute and odourless.
  • People with diabetes insipidus have normal blood glucose levels; however, their kidneys cannot balance fluid in the body. 
  • Hence, the Urine of a human being suffering from diabetes insipidus is Tasteless and watery.
  • So, the correct answer is 'Tasteless and watery'.
Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

Even in presence of hormone ADH, maximum water is reabsorbed in?

  1. Proximal convoluted tubule

  2. Distal convoluted tubule

  3. Both DCT and collecting tubule

  4. Loop pf Henle
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Over 180 liters of urine is produced in the human body every day. Out of this, only 1.5 liters is actually excreted. This means that 99% of the urine produced is reabsorbed in the body. Various solutes are absorbed in different parts of the renal tubule. Maximum water absorption takes place in the proximal convoluted tubule. 

So, the correct answer is 'Proximal convoluted 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

Which of the following is involved in reabsorption of water in kidney?

  1. ADH

  2. PRL

  3. LH

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

Antidiuretic hormone or ADH ( also known as vasopressin ) is involved in reabsorption of water in kidney. Antidiuretic hormone binds to receptors on cells in the collecting ducts of the kidney and promotes reabsorption of water back into the circulation. In the absense of antidiuretic hormone, the collecting ducts are virtually impermiable to water, and it flows out as urine.

Antidiuretic hormone stimulates water reabsorbtion by stimulating insertion of "water channels" or aquaporins into the membranes of kidney tubules. These channels transport solute-free water through tubular cells and back into blood, leading to a decrease in plasma osmolarity and an increase osmolarity of urine.
So, the correct option 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

Which of the following is a powerful vasconstrictor that increases the glomerular blood pressure and there the GFR?

  1. Renin

  2. Angiotensin-II

  3. Aidosterone

  4. ANF
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Osmoreceptors in the body are activated by changes in blood volume, body fluid volume and ionic concentration. 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.
So, the correct option is 'Angiotensin-II'.
Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

Osmoregulation is carried out by

  1. Ureter

  2. Nephron

  3. ACTH

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

The maintenance of constant osmotic pressure in the fluids of an organism by the control of water and salt concentrations. is called Osmoregulation. It  is carried out by 'anti-diuretic hormone'. 

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

Vasopressin is responsible for :-

  1. Making urine dilute

  2. Dialating the blood vessel

  3. Decreasing filtrate concentration in PCT

  4. Increasing blood pressure
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Vassopressin or anti-diuretic hormone helps prevent loss of water from the body by increasing the reabsorption of water from the kidney and making urine more concentrated. It is also responsible for increasing the blood pressure by constricting the blood vessels. So, the correct option is 'increasing 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

Acidification of urine occurs in

  1. Proximal tubule

  2. Distal tubule

  3. Loop of henle

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

The proximal convoluted tubule is the primary site for the reabsorption of bicarbonate and the secretion of hydrogen ions, which contributes to the acidification of 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 one of the following statements is correct with respect to kidney function regulation?

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

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

  3. Exposure to cold temperatures stimulates ADH release

  4. An increase in glomerular blood flow stimulates formation of angiotensin II
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When the level of water in blood goes up for example in cold or when we had a lot to drink, the hypothalamus detects the change and sends a message to the pituitary. The release of ADH into the blood is slowed down or even stopped. Without ADH the kidneys will not save as much water and we produce large volumes of dilute urine. The level of water in the blood falls back to the normal level.

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 water is reabsorbed under the influence of ADH. it is

  1. Active reabsorption

  2. Obligatory reabsorption

  3. Facultative

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The reabsorption of water in the earlier parts of the nephron (regardless of a person's state of hydration), independent of ADH is termed as 'obligatory reabsorption of water', whereas the water reabsorption in the distal part of the nephron (in accordance with the body's state of hydration), under the influence of ADH, is termed as 'facultative reabsorption of water'.
In facultative reabsorption, the collecting ducts become more permeable to water due to the effect of ADH, so water is reabsorbed by osmosis. Osmosis is a passive process (the diffusion of water from an area of higher water concentration to an area of lower water concentration), no expenditure of ATP energy is required in it.
Thus water reabsorption under the influence of ADH is facultative and passive reabsorption.

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 causes which one of the following?

  1. Increase in reabsorption of water

  2. Decrease in reabsorption of water

  3. Maintenance of equilibrium of Na and Ca ion balance

  4. Maintenance of equilibrium of K ion and carbonate pump
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Vasopressin also known as antidiuretic hormone (ADH), is a neurohypophysial hormone found in most mammals. Its two primary functions are to retain water in the body and to constrict blood vessels. Antidiuretic hormone binds to receptors on cells in the collecting ducts of the kidney and promotes reabsorption of water back into the circulation. In the absence of antidiuretic hormone, the collecting ducts are virtually impermeable to water, and it flows out as urine.