Test: Excretory Products & their Elimination - 2 - NEET MCQ

The correct option is Option D.
DCT is capable of reabsorption of HCO3 – and selective secretion of hydrogen and potassium ions and NH3 to maintain the pH and sodium-potassium balance in blood.

Topic in NCERT: Distal convoluted tubule

Line in NCERT: "DCT is also capable of reabsorption of HCO3 and selective secretion of hydrogen and potassium ions and NH to maintain the pH and sodium-potassium balance in blood."

Sodium reabsorption occurs through tubular reabsorption in proximal and distal convoluted tubules only. The proximal convoluted tubule is involved in active reabsorption of sodium into the peritubular capillary network and passive flow of water flows. It accounts for 67% of sodium reabsorption. DCT reabsorption of sodium is also an active process but is under hormonal regulation i.e., conditional response. 
Therefore, the correct answer is option D.

Topic in NCERT: Proximal convoluted tubule

Line in NCERT: "Proximal Convoluted Tubule (PCT): PCT is lined by simple cuboidal brush border epithelium which increases the surface area for reabsorption. Nearly all of the essential nutrients, and 70-80 per cent of electrolytes and water are reabsorbed by this segment."

When both and kidney of a person get damaged and not able to filter the blood, dialysis is used to remove nitrogenous wastes. High wastes accumulation unable a woman to conceive. The ultimate solution to this problem is kidney transplant.

Topic in NCERT: Kidney transplantation

Line in NCERT: "Kidney transplantation is the ultimate method in the correction of acute renal failures (kidney failure)."

Vasa recta is absent or highly reduced in cortical nephrons.

Topic in NCERT: Vasa recta in cortical nephrons

Line in NCERT: "Vasa recta is absent or highly reduced in cortical nephrons."

A fall in glomerular blood flow/glomerular blood pressure/GFR can activate the JG cells to releasereninwhich converts angiotensinogen in blood to angiotensin I and further to angiotensin II.

Topic in NCERT: Renin-angiotensin mechanism

Line in NCERT: "The JGA plays a complex regulatory role. A fall in glomerular blood flow/glomerular blood pressure/GFR can activate the JG cells to release renin which converts angiotensinogen in blood to angiotensin I and further to angiotensin II."

The production of red blood cells is not a function of the kidneys. This process primarily occurs in the bone marrow. The kidneys do produce erythropoietin, which stimulates red blood cell production, but they do not produce the cells themselves.

Towards the centre of the inner concave surface of the kidney is a notch called hilum through which ureter, blood vessels and nerves enter.

Topic in NCERT: Hilum

Line in NCERT: "Towards the centre of the inner concave surface of the kidney is a notch called hilum through which ureter, blood vessels and nerves enter."

K⁺ and HCO₃^- ions are secreted by active transport into the filtrate in the distal convoluted tubule.

Topic in NCERT: Distal convoluted tubule

Line in NCERT: "the distal convoluted tubule (DCT) is also capable of reabsorption of HCO3 and selective secretion of hydrogen and potassium ions"

The renal vein takes blood away from the kidney. The process starts with renal artery which enters the kidney as afferent arteriole. It carries the urea loaded blood into the glomerulus of the kidney. The blood is filtered by the glomerulus into the Bowman's capsule and runs parallel to the loop of Henle. The urea is absorbed into the nephric filtrate by the process of tubular secretion in the loop of Henle, distal convulated tubule and collecting duct. The process of tubular secretion helps to secrete the urea from the blood to the collecting duct which is finally excreted in form of urine. The purified blood comes from the kidney through the renal vein and drained into vena cava outside kidney.
So, the correct answer is 'Renal vein'.

Topic in NCERT: Efferent arteriole

Line in NCERT: "Blood from the glomerulus is carried away by an efferent arteriole."

• Nephrons are the functional unit of the kidney.
• These are the structures which actually produce urine in the process of removing waste and excess substances from the blood.
• There are about 10,00,000 nephrons in each human kidney.

Topic in NCERT: Collecting duct

Line in NCERT: "Collecting Duct: This long duct extends from the cortex of the kidney to the inner parts of the medulla. Large amounts of water could be reabsorbed from this region to produce a concentrated urine."

The excretory system in human consistsof a pair of kidneys, one pair of ureters, aurinary bladder and a urethra. Kidneys are reddish brown, bean shaped structures situated between the levels of last thoracic and third lumbarvertebra close to the dorsal inner wall of the abdominal cavity.

Topic in NCERT: Human excretory system

Line in NCERT: "In humans, the excretory system consists of a pair of kidneys, one pair of ureters, a urinary bladder and a urethra." "Kidneys are reddish brown, bean shaped structures situated between the levels of last thoracic and third lumbar vertebra close to the dorsal inner wall of the abdominal cavity."

The dilation of blood vessels leads to a decrease in peripheral resistance and a decrease in blood pressure, while constriction of blood vessels leads to an increase in peripheral resistance and an increase in blood pressure.

The counter current mechanism, established by the flow of filtrate in opposite directions in the Henle's loop and the vasa recta, plays a crucial role in the concentration of urine in mammals. This mechanism allows for the exchange of NaCl and urea between the ascending limb of Henle's loop and the descending limb of vasa recta, contributing to the increasing osmolarity towards the inner medullary interstitium. This process aids in the maintenance of a concentration gradient necessary for the reabsorption of water and essential substances in the nephron, thereby enabling the production of concentrated urine.

Topic in NCERT: Counter current mechanism

Line in NCERT: "The flow of filtrate in the two limbs of Henle's loop is in opposite directions and thus forms a counter current."

The mechanism that aids in the concentration of filtrate in mammals' urine production is known as the counter current mechanism. This mechanism involves the flow of filtrate in opposite directions in the two limbs of Henle's loop, as well as the counter current flow of blood through the two limbs of vasa recta. This specialized arrangement, along with the proximity between the Henle's loop and vasa recta, plays a crucial role in maintaining an increasing osmolarity towards the inner medullary interstitium.

Topic in NCERT: Mechanism of concentration of the filtrate

Line in NCERT: "the above described transport of substances facilitated by the special arrangement of Henle's loop and vasa recta is called the counter current mechanism"

Renal calculi are characterized by the presence of an insoluble mass of crystallized salts within the kidney. These formations can vary in size and composition, often leading to symptoms such as severe pain, hematuria (blood in urine), and urinary obstruction. It is crucial to manage these calculi through dietary changes, hydration, and medical interventions to prevent complications like kidney damage or recurrent stone formation.

Topic in NCERT: Renal calculi

Line in NCERT: "Renal calculi: Stone or insoluble mass of crystallised salts (oxalates, etc.) formed within the kidney."