Question
Select the correct statement. [NEET (Oct.) 2020]
(a) Atrial Natriuretic Factor increases the blood pressure
(b) Angiotensin II is a powerful vasodilator
(c) Counter-current pattern of blood flow is not observed in vasa recta
(d) Reduction in Glomerular Filtration Rate(GFR) activities JG cells to release renin
Answer/Explanation
Ans. (d)
Statement in option (d) is correct as a reduction in glomerular filtration rate activate the JG cells to release renin which converts angiotensinogen in blood to angiotensin-I. Other statements are incorrect and can be corrected as Atrial Natriuretic Factor (ANF) causes vasodilation and thereby decreases the blood pressure.Angiotensin-1l is a powerful vasoconstrictor, it increases the GFR.
Counter-current pattern of blood flow is observed in vasa recta.
Question
Which of the following factors is responsible for the formation of concentrated urine? [NEET (National) 2019]
(a) Maintaining hyperosmolarity towards inner medullary interstitium in the kidneys
(b) Secretion of erythropoietin by juxtaglomerular complex
(c) Hydrostatic pressure during glomerular filtration
(d) Low levels of antidiuretic hormone
Answer/Explanation
Ans. (a)
Maintaining hyperosmolarity towards inner medullary interstitium in the kidneys is the factor responsible for the formation of concentrate urine because it provides concentration gradient necessary for water reabsorption in renal tubules. Erythropoietin secretion by juxtaglomerular complex is related to red blood cell production and hydrostatic pressure during glomerular filtration to amount of filtrate formed by kidneys.
High levels of antidiuretic hormone and not low levels produce urine that is more concentrated.
Question
A decrease in blood pressure/volume will not cause the release of [NEET 2017]
(a) renin
(b)atrial natriuretic factor
(c) aldosterone
(d) $\mathrm{ADH}$
Answer/Explanation
Ans. (b)
A decrease in blood pressure/volume stimulates the hypothalamus to release ADH (Anti Diuretic Hormone) as well as JGA (Juxtaglomerular Apparatus) cells to release renin. Renin by renin angiotensin mechanism activates the adrenal cortex to release aldosterone.
Atrial Natriuretic Factor (ANF) is produced by atria of heart during increased blood pressure/volume. It can cause vasodilation and there by. decrease the blood pressure, therefore, option (b) is correct
Question
Human urine is usually acidic because [CBSE AIPMT 2015]
(a) the sodium transporter exchanges one hydrogen ion for each sodium ion, in peritubular capillaries
(b) excreted plasma proteins are acidic
(c) potassium and sodium exchange generates acidity
(d) hydrogen ions are actively secreted into the filtrate
Answer/Explanation
Ans. (d)
The proximal tubule is the portion of nephron of the kidney which leads from the Bowman’s capsule to the loop of Henle.
It regulates the $\mathrm{pH}$ of the filtrate by exchanging hydrogen ions in the interstitium for bicarbonate ions in the filtrate. Due to the $\mathrm{H}^{+}$ions the human urine is usually acidic. Thus $\mathrm{H}^{+}$are actively secreted into the filtrate is the correct option.
Question
Which one of the following statements is correct with respect to kidney function regulation? [CBSE AIPMT 2011]
(a) Exposure to cold temperature stimulates $A D H$ release
(b) An increase in glomerular blood flow stimulates formation of angiotensin-II
(c) During summer when body loses lot of water by evaporation, the release of $\mathrm{ADH}$ is suppressed
(d) When someone drinks lot of water ADH release is stopped
Answer/Explanation
Ans. (d)
When someone drinks lot of water which is not required by body, the osmoregulation of the blood will decrease. The decrease in osmoregulation will inhibit the release of $\mathrm{ADH}$.
Question
A person who is on a long hunger strike and is surviving only on water, will have [CBSE AIPMT 2007]
(a) more sodium in his urine
(b) less amino acids in his urine
(c) more glucose in his blood
(d) less urea in his urine
Answer/Explanation
Ans. (d)
A person who is on a long hunger strike and is surviving only on water, will have less urea in his urine.As urea is an organic compound which is a waste product produced during body metabolism.
Question
Angiotensinogen is a protein produced and secreted by [CBSE AIPMT 2006]
(a) macula densa cells
(b) endothelial cells (cells lining the blood vessels)
(c) liver cells
(d) Juxtaglomerular (JG) cells
Answer/Explanation
Ans. (c)
Angiotensinogen is a plasma protein produced and secreted by the liver cells. Renin is secreted from juxtaglomerular cells and acts enzymatically on angiotensinogen to release 10 amino acid contaning peptide angiotensin-I. Macula densa is actually a plaque in wall at the end of thick assending limb of nephrons.
Question
A person is undergoing prolonged fasting. His urine will be found to contain abnormal quantities of [CBSE AIPMT 2005]
(a)fats
(b) ketones
(c) amino acids
(d) glucose
Answer/Explanation
Ans. (b)
If a person is undergoing prolonged fasting, his urine will be found to contain abnormal quantities of ketones. During fasting energy is obtained by the oxidation of reserved fats. As a result of fatty acid oxidation large amount of ketone bodies are produced such as acetoacetate, $\beta$-hydroxybutyrate and acetone.
Question
Glucose is taken back from glomerular filtrate through [CBSE AIPMT 1993]
(a) active transport
(b) passive transport
(c) osmosis
(d) diffusion
Answer/Explanation
Ans. (a)
Glucose is taken back from glomerular filtrate through active transport in proximal convoluted tubule.