FREE NEET Biology Practice MCQ Test: Excretory Products And Their Elimination Exercise 3 Questions Answers With Detailed Explanations [PDF]

Answer: (a)

Answer: (d)

Glomerulus is a tuft of capillaries formed by afferent arteriole(a fine branch of renal artery).

Answer: (a)

Concentration of urine depends upon the length of Henle's loop. Loop of Henle is the hairpin shaped section of a kidney tubule situated between the proximal and distal tubules in the nephron. It consists of a thin descending limb which is permeable to water and a thick ascending limb which is impermeable to water complex movements of ions and water across the walls of the loop enable it to function as a countercurrent multiplier, resulting in the production of concentrated urine in the collecting duct.

Answer: (c)

Urine is hypertonic in the middle of descending and ascending limb of Henle’s loop.

Answer: (c)

Urea $NH_{2} – CO – NH_{2}$ is formed from two molecules of ammonia and one molecule of carbon dioxide. A molecule of ammonia combines with carbon dioxide to form carbonyl phosphate. It reacts with ornithine to form citrulline. Citrulline accepts another molecule of NH4+ giving rise to arginine. Arginine is hydrolysed into urea and ornithine with the help of enzyme arginase.

Answer: (c)

In comparison to blood plasma, percentage of glucose in glomerular filtrate is equal.

Answer: (b)

Lysozyme is an antibacterial agent which is secreted by the major salivary glands.

Answer: (c)

Answer: (a)

The amount of the filtrate formed by the kidneys per minute is called glomerular filtration rate (GFR). GFR in a healthy individual is approximately 125 ml/minute, i.e., 180 litres per day. A fall in GFR can activate the JG cells to release renin which can stimulate the glomerular blood flow and thereby the GFR back to normal. Renin converts angiotensinogen in blood to angiotensin I and further angiotensin II. Angiotensin II being powerful vasoconstrictor increases the glomerular blood pressure and thereby GFR.

Answer: (b)

Answer: (c)

Answer: (a)

Answer: (a)

A nephron is a unit of structure and function in a kidney. A kidney contains about a million nephrons, each approximately 3 cm long.

A nephron is a long tubule differentiated into four regions having different anatomical features and physiological role : Bowman's capsule, proximal convoluted tubule (PCT), loop of Henle, and distal convoluted tubule (DCT). The latter opens into one of the collecting ducts. Nephridia are the excretory organs of annelids.

Answer: (d)

Renal artery and ureter carries the waste products. Renal vein carries pure blood back to the heart.

Answer: (b)

Answer: (a)

Liver is the primary site of detoxification and elimination of body wastes and poisons. Liver detoxifies endotoxins, e.g. toxic $NH_3$ combined with $CO_2$ to form less toxic urea. It also detoxifies alcohol and convert them to acetaldehyde and then harmless acetyl CoA.

Answer: (b)

When someone drinks lots of water, release of ADH is suppressed.

Answer: (c)

Uremia is the accumulation of urea in blood. It occurs due to malfunctioning of kidney.

Renal calculi refers to the formation of stones or insoluble mass of crystallised salts (oxalates. etc) with in the kidney.

Glomerulonephritis is the inflammation of glomeruli of kidney.

Ketonuria is a medical condition in which ketone bodies are present in the urine. It is normally seen during starvation or more commonly in type 1 diabetes mellitus.

Answer: (d)

During states of dehydration, the hormone ADH (anti-diuretic hormone) is produced, which increases the permeability of the collecting ducts and increases water reabsorption.

Answer: (c)