Tag: excretory system of human

Questions Related to excretory system of human

Number of mitochondria is maximum in part of uriniferous tubule

zoology excretory system of human structure of nephron excretory system nephron

  1. PCT

  2. Loop of Henle

  3. DCT

  4. Bowmans capsule

Show answer
Correct Option: A
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'.

Under low glomerular blood flow, juxta glomerular cells release

zoology excretory system of human structure of nephron excretory system nephron

  1. Angiotensin I

  2. Angiotensin II

  3. Aldosterone

  4. Renin

Show answer
Correct Option: D
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'.

Juxtaglomerular apparatus is made of

zoology excretory system of human structure of nephron excretory system nephron

  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

Show answer
Correct Option: A
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'.

A fall in glomerular filtration rate activates

zoology excretory system of human structure of nephron excretory system nephron

  1. Juxtaglomerular cells to release renin

  2. Adrenal cortex to release aldosterone

  3. Posterior pituitary to release vasopressin

  4. Adrenal medulla to release adrenaline

Show answer
Correct Option: A
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'.

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

zoology excretory system of human structure of nephron excretory system nephron

  1. a-Renin, b-Chloride

  2. a-Carbonic anhydrase, b-Sodium

  3. a- ATPase, b-Potassium

  4. a-Renin, b-Sodium

Show answer
Correct Option: D
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'.

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

zoology excretory system of human structure of nephron excretory system nephron

  1. Descending loop of Henle

  2. Collecting tubule

  3. Ascending loop of Henle

  4. None of the above

Show answer
Correct Option: C
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'

Cells of macula densa produce

zoology excretory system of human structure of nephron excretory system nephron

  1. Erythropoietin

  2. Renin

  3. Angiotensinogen

  4. Angiotensin

Show answer
Correct Option: B
Explanation:

Macula densa are specialized cells present in the distal convoluted tubule of nephron where distal convoluted tubule come in contact with the afferent renal arteriole of the glomerulus. When blood volume has decreased the cells of macula densa give signals to juxtaglomerular cells to secrete renin enzyme. Hence cells of macula densa produce renin in response to low blood volume by stimulating juxtaglomerular cells.

So, the correct answer is 'Renin'.

Juxta-glomerular cells form

zoology excretory system of human structure of nephron excretory system nephron

  1. Angiotensinogen and angiotensin

  2. Renin and erythropoietin

  3. Counter-current

  4. Selective secretory and absorptive apparatus

Show answer
Correct Option: B
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'.

Which one is the diluting segments of uriniferous tubule?

zoology excretory system of human structure of nephron excretory system nephron

  1. Ascending loop of Henle

  2. Descending loop of Henle

  3. PCT

  4. DCT

Show answer
Correct Option: A
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'.

What conditions are responsible for stimulation of juxtaglomerular apparatus?

zoology excretory system of human structure of nephron excretory system nephron

  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.

Show answer
Correct Option: D
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'.