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 excretory system of human structure of nephron excretory system nephron

Juxtaglomerular cells of renal cortex synthesises an enzyme called 

  1. ADH

  2. Oxytocin

  3. Renin

  4. Urochrome

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

Renin is produced in the kidney by the juxtaglomerular cells of renal cortex. It participates in the renin–angiotensin–aldosterone system which maintains the blood pressure and fluid balance in the body. It breaks the angiotensinogen secreted from the liver into a peptide angiotensin I. Angiotensin I is further cleaved into angiotensin II. Angiotensin II acts on the adrenal glands and releases aldosterone which acts on the collecting tubules to absorb more sodium ions which in turn increases the absorption of water and increases the blood volume.  It also acts on the CNS to increase water intake by stimulating thirst. So the correct answer is 'Renin'.

Multiple choice zoology excretory system of human structure of nephron excretory system nephron

Which of the following processes creates high osmotic pressure in uriniferous tubule?

  1. Active secretion of $Na^+$ into efferent arteriole followed by Cl secretion
  2. Active $Na^+$ absorption followed by Cl absorption
  3. Active secretion of $Cl^-$ and absorption of $Na^+$ into efferent arteriole
  4. Active Cl absorption followed by absorption of $Na^+$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The nephron is the structural and functional unit of the kidney. It is also called as uriniferous tubule. The active absorption of Na+ ion followed by the absorption of Cl created high osmotic pressure in the uriniferous tubule.

So, the correct answer is 'Active Na+ absorption followed by Cl absorption'.

Multiple choice zoology excretory system of human structure of nephron excretory system nephron

Number of mitochondria is maximum in part of uriniferous tubule

  1. PCT

  2. Loop of Henle

  3. DCT

  4. Bowmans capsule
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Proximal convoluted tubule (PCT) is lined with cuboidal epithelium with brush border. Almost all essential nutrients and 70-80 % of electrolytes and water are reabsorbed by PCT. The maximum number of mitochondria are present in PCT as the mitochondria support energy requirements of the sodium-potassium pump.
So, the correct answer is 'PCT'.
Multiple choice zoology excretory system of human structure of nephron excretory system nephron

Under low glomerular blood flow, juxta glomerular cells release

  1. Angiotensin I

  2. Angiotensin II

  3. Aldosterone

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

Juxta-glomerular cells are specialized smooth muscle cells of the afferent arteriole, which supplies blood to the glomerulus. When the kidney receives the low volume of blood (low glomerular blood flow)the juxtaglomerular cells are stimulated to release renin.

So, the correct answer is 'Renin'.

Multiple choice zoology excretory system of human structure of nephron excretory system nephron

Juxtaglomerular apparatus is made of

  1. Juxtaglomerular cell, macula densa and lacis cell

  2. Juxtaglomerular cell, lacis cell and myoepithelial cell

  3. Juxtaglomerular cell, lacis cell and Purkinje cell

  4. Juxtaglomerular cell, macula densa and argentaffin cell
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Juxtaglomerular apparatus is a part of nephron present beside glomerulus. These are specialized cells where afferent arteriole come in contact with distal convoluted tubule. The Juxtaglomerular apparatus is made up of the Juxtaglomerular cells(specialized smooth muscle cells of the afferent arteriole), macula densa( specialized cells present in the distal convoluted tubule) and lacis cell.
So, the correct answer is 'Juxtaglomerular cell, macula densa and lacis cell'.
Multiple choice zoology excretory system of human structure of nephron excretory system nephron

A fall in glomerular filtration rate activates

  1. Juxtaglomerular cells to release renin

  2. Adrenal cortex to release aldosterone

  3. Posterior pituitary to release vasopressin

  4. Adrenal medulla to release adrenaline
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The juxtaglomerular apparatus is a specialized structure formed by the distal convoluted tubule and the glomerular afferent arteriole. It consists of three cell types: The macula densa, juxtaglomerular cells, and extraglomerular mesangial cells. A fall in glomerular filtration rate activates juxtaglomerular cells to release renin. Renin increases blood pressure via the renin-angiotensin-aldosterone system.

So, the correct answer is 'Juxtaglomerular cells to release renin'.

Multiple choice zoology excretory system of human structure of nephron excretory system nephron

Juxtaglomerular cells secrete _________(a) when there is fall in blood pressure (b) ______ ion concentration. Choose the correct option.

  1. a-Renin, b-Chloride

  2. a-Carbonic anhydrase, b-Sodium

  3. a- ATPase, b-Potassium

  4. a-Renin, b-Sodium
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Juxta-glomerular cells are specialized smooth muscle cells of the afferent arteriole, which supplies blood to the glomerulus. When the kidney receives the low volume of blood the juxtaglomerular cells are stimulated to release Renin.renin  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.

So, the correct answer is 'a-Renin, b-Sodium'.

Multiple choice zoology excretory system of human structure of nephron excretory system nephron

In which part uriniferous tubule, $Na^+$ passes out

  1. Descending loop of Henle

  2. Collecting tubule

  3. Ascending loop of Henle

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

The nephron is the structural and functional unit of the kidney. It is also called as uriniferous tubule. During the process of urine formation in nephron certain substances are secreted (passes out) and some are reabsorbed along the length of the nephron. The ascending loop of Henle is impermeable to water but allows transport of electrolytes like  Na(+). ions actively or passively.

So, the correct answer is 'Option C'

Multiple choice zoology excretory system of human structure of nephron excretory system nephron

Juxta-glomerular cells form

  1. Angiotensinogen and angiotensin

  2. Renin and erythropoietin

  3. Counter-current

  4. Selective secretory and absorptive apparatus
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Juxta-glomerular cells are specialized smooth muscle cells of the afferent arteriole, which supplies blood to the glomerulus. When the kidney receives the low volume of blood the juxtaglomerular cells are stimulated to release Renin. When the blood received by kidney have low oxygen levels these cells secrete erythropoietin hormone.
So, the correct answer is 'Renin and erythropoietin'.
Multiple choice zoology excretory system of human structure of nephron excretory system nephron

Which one is the diluting segments of uriniferous tubule?

  1. Ascending loop of Henle

  2. Descending loop of Henle

  3. PCT

  4. DCT
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The cells of ascending limb actively reabsorb solutes from the luminal fluid and are impermeable to water. As the ions leave the lumen the concentration becomes more and more hypotonic until it reaches approximately 100-150 mOsm/L. The ascending limb is also called the diluting segment of the uriniferous tubule or nephron because of its ability to dilute the fluid in the loop from 1200 mOsm/L to 100 mOsm/L.
So, the correct answer is 'Ascending loop of Henle'.
Multiple choice zoology excretory system of human structure of nephron excretory system nephron

What conditions are responsible for stimulation of juxtaglomerular apparatus?

  1. An increase in blood pressure or blood volume in heart.

  2. An increase in the solute concentration the blood plasma.

  3. A decrease in the solute concentration oil the blood plasma.

  4. Decrease in blood pressure or blood volume in afferent arteriole.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
The juxtaglomerular apparatus is a specialized structure formed by the distal convoluted tubule and the glomerular afferent arteriole. It consists of three cell types: The macula densa, juxtaglomerular cells, and extraglomerular mesangial cells. When the blood pressure or blood volume in afferent arteriole is decreased this condition stimulates the juxtaglomerular cells present in the juxtaglomerular apparatus. The juxtaglomerular cells, derived from smooth muscle cells, of the afferent arteriole, secrete renin when blood pressure in the arteriole falls. Renin increases blood pressure via the renin-angiotensin-aldosterone system. This decrease in blood pressure or blood volume in afferent arteriole is responsible for stimulation of juxtaglomerular apparatus.
So, the correct answer is 'option D'.
Multiple choice zoology excretory system of human structure of nephron excretory system nephron

The nephrons discharge their urine at the:

  1. Urinary bladder

  2. Urethra

  3. Renal pelvis

  4. Renal pyramid (calyses)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The renal pelvis or pelvis of the kidney is the funnel-like dilated part of the ureter in the kidney. In humans, the renal pelvis is the point where the two or three major calyces join together. Renal pelvis, enlarged upper end of the ureter, the tube through which urine flows from the kidney to the urinary bladder.


So, the correct answer is 'Renal pelvis'.

Multiple choice zoology excretory system of human structure of nephron excretory system nephron

Which is true about the difference between cortical and juxtamedullary nephrons? 

  1. Most nephrons are juxtamedullary.

  2. The efferent arteriole's of cortical nephrons give rise to most of the vasa recta.

  3. The aaferent arterioles of the juxtamedullary nephrons give rise to most of the vasa recta.

  4. Juxtamedullary nephrons generate a hyperosmotic medullary interstitium.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Cortical nephrons either have short or absent loops of Henle. Only juxtamedullary nephrons have long loops of Henle, which plunge into the renal medulla and create a hypersomotic interstitium via counter current multiplication. 

So the correct option is D.

Multiple choice zoology excretory system of human structure of nephron excretory system nephron

Of the total nephrons,the juxtamedullary nephrons constitute ........... %.

  1. 15

  2. 45

  3. 65

  4. 85
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Nephron is the structural and functional unit of the kidney. Juxtamedullary nephrons are found only in birds and mammals. These are juxtamedullary on the basis of their Loop of Henle which is deep in the renal medulla and the renal corpuscle is in the medulla and only around 15-20% of the nephrons are juxtamedullary.