Tag: zoology

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Questions Related to zoology

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

Cells of macula densa produce

  1. Erythropoietin

  2. Renin

  3. Angiotensinogen

  4. Angiotensin
Reveal answer Fill a bubble to check yourself
B Correct answer
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'.

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

A Malpighian body is constituted by 

  1. Glomerulus only

  2. Glomerulus and Bowman's capsule

  3. Glomerulus and Efferent vessel

  4. Glomerulus, Bowman's capsule and Efferent vessel
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A malphagian body is constituted of two parts - Glomerulus and Bowman's capsule. The glomerulus is the tuft of capillaries and has the filtering apparatus. The Bowman's capsule has a cup-like sack present at the beginning of the tubular component of a nephron.

So, the correct answer is (B).