Q.1. Which of the following factors is responsible for the formation of concentrated urine? (2019)
(a) Hydrostatic pressure during glomerular filtration.
(b) Low levels of antidiuretic hormone.
(c) Maintaining liyperosmolarity towards the medullary interstitium in the kidneys.
(d) Secretion of erythropoietin by Juxtaglomerular complex.
The counter current mechanism helps to maintain a concentration gradient in the medullary mterstitium. The proximity between the Henle’s loop and vasa recta, as well as the counter current in them help in maintaining an increasing osmolarity towards the inner medullary interstitium, i.e., from 300 mOsmoIL-1 in the cortex to about 1200 mOsmolL-1 m the inner medulla. This gradient is mainly caused by NaCl and urea. Presence of such interstitial gradient helps in an easy passage of water from the collecting tubule thereby concentrating the filtrate (urine).
Q.2. Use of an artificial kidney during hemodialysis may result in
(A) Nitrogenous waste build-up in the body
(B) Non-elimination of excess potassium ions
(C) Reduced absorption of calcium ions from gastro-intestinal tract
(D) Reduced RBC production.
Which of the following options is the most appropriate? (2019)
(a) (A) and (D) are correct.
(b) (A) and (B) are correct.
(c) (B) and (C) are correct.
(d) (C) and (D) are correct.
When kidneys are completely damaged and do not function, patient often receive hemodialysis (treatment with artificial kidney). The Patient is connected to the machine by a tube attached to an artery often the radial artery. Blood from the artery is pumped int0 a tube that runs through the dialyser. The dialyser is filled with dialysing fluid which contains the same quantities of electolytes and nutrients as normal plasma but contains no waste products. The cellophane tube (a tube bounded by thin membrane) is kept in the dialysing fluid. The membrane of the cellophane tube is impermeable to blood cells and proteins but permeable to urea, uric acid, creatinine and mineral ions. So, these wastes diffuse Irom tlie blood to the dialysing fluid across the cellophane membrane.
However, since both kidneys arc non-functional thus absorption of Ca2+ from small intestine will be affected as coversion of vitamin D to calcitriol will not take place which is needed for calcium absorption from small intestine(Gl tract). Erythropoietin production will also be affected, thus RBC production will be reduced.
Q.3. Match the items given in column I with those in column II and select the correct option given below. (2018)
|Column I||Column II|
|A. Glycosuria||(i) Accumulation of uric acid in joints|
|B. Gout||(ii) Mass of crystallised salts within the kidney|
|C. Renal calculi||(iii) Inflammation in glomeruli|
|D. Glomerular nephritis||(iv) Presence of glucose in urine|
Q.4. Match the items given in column I with those in column II and select the correct option eiven below. (2018)
|Column I (Function)||Column II (Part of excretory system)|
|A. Ultrafiltration||(i) Henle's loop|
|B. Concentration of urine||(ii) Ureter|
|C. Transport of urine||(iii) Urinary bladder|
|D. Storage of urine||(iv) Malpighian corpuscle|
|(v) Proximal convoluted tubule|
Q.5. A decrease in blood pressure/volume will not cause the release of (2017)
(a) Atrial natriuretic factor
Atrial natriuretic factor (ANF) is responsible for lowering of blood pressure and volume. The walls of the atria of the heart release ANF in response to an increase in blood volume and pressure. It opposes regulation by RAAS. It inhibits release of renin from JGA thereby inhibiting NaCl reabsorplion by the collecting duct and reduces aldosterone release from adrenal gland.
Q.6. Which of the following statements is correct? (2017)
(a) The descending limb of loop of Henle is impermeable to water.
(b) The ascending limb of loop of Henle is permeable to water.
(c) The descending limb of loop of Henle is permeable to electrolytes.
(d) The ascending limb of loop of Henle is impermeable to water.
Descending limb of loop of Henle is permeable to water but impermeable to electrolytes. Ascending limb of loop of Henle is impermeable to water but permeable to electrolytes.
Q.7. The part of nephron involved in active reabsorption of sodium is (2016)
(a) Distal convoluted tubule
(b) Proximal convoluted tubule
(c) Bowman’s capsule
(d) Descending limb of Henle’s loop.
From the Bowman’s capsule, a glomerular filtrate enters the proximal convoluted tubule. Absorption of selected materials takes place from the filtrate into the blood of the peritubular capillaries or vasa recta. It is termed the tubular reabsorption. Reabsorplion involves both passive and active transport across the tubular epithelium. About 65 percent of the glomerular filtrate is normally reabsorbed in the proximal convoluted tubule before reaching the loop of Henle. Glucose, amino acids, vitamins, hormones, sodium, potassium, chlorides, phosphates, bicarbonates, much of water and some urea from the filtrate are absorbed. Sodium and potassium are reabsorbed by primary active transport.
Q.8. In mammals, which blood vessel would normally carry largest amount of urea? (2016)
(a) Renal Vein
(b) Dorsal Aorta
(c) Hepatic Vein
(d) Hepatic Portal Vein
Hepatic Vein, because the liver produces urea and other waste materials and then it pours it all in the right ventricle of the heart for oxygenation. The heart distributes the blood to various parts of the body from here. So the impure blood brought by the Hepatic Vein and other blood vessels get distributed through the aorta. This will automatically imply that the Renal Artery will contain lesser impure blood than the Hepatic Vein.
Q.9. Which of the following does not favour the formation of large quantities of dilute urine? (2015)
(c) Atrial-natriuretic factor
The secretion of Renin is induced by decrease in blood pressure and blood volume. It maintains the proper BP and BV. It has no role in the formation of large quantities of urine.
Q.10. Removal of proximal convoluted tubule from the nephron will result in: (2015)
(a) More concentrated urine
(b) No change in quality and quantity of urine
(c) No urine formation
(d) More diluted urine
Gnerally all of the essential nutrients and 70% to 80% of electrolytes and water are reabsorbed by this segment. Removal of proximal convolnted tubule from the nephron will result in dilution of urine.
Q.11. Human urine is usually acidic because: (2015)
(a) Excreted plasma proteins are acidic
(b) Potassium and sodium exchange generates acidity
(c) Hydrogen ions are actively secreted into the filtrate.
(d) The sodium transporter exchanges one hydrogen ion for each sodium ion, in peritubular capillaries.
Urine has acidic nature because hydrogen ions(H+) are components of an acid which are secreted into the filtrate.
Q.12. Which of the following causes an increase in sodium reabsorption in the distal convoluted tubule? (2014)
(a) Increase in aldosterone levels
(b) Increase in antidiuretic hormone levels
(c) Decrease in aldosterone levels
(d) Decrease in antidiuretic hormone levels
Aldosterone hormone, released by the adrenal glands, helps the body regulate blood pressure. Aldosterone causes the tubules of the kidneys to increase the reabsorption of sodium and water into the blood. This increases the volume of fluid in the body, which also increases blood pressure.