Assertion : Secreting hypotonic urine is effective in reducing urinary loss of water.
Reason : Hypotonic urine is more concentrated and higher in osmotic pressure than the blood.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
D.
If both assertion and reason are false
When there is a threat of excessive water loss from the body of the animal, then the urine excreted needs to be hypertonic and not hypotonic. This is due to the reason as excessive water loss from the body possess the threat of a rise in osmoconcentration of the blood. Since hypertonic urine is more concentrated and higher in osmotic pressure than the blood, therefore it helps in reducing the loss of water with urine.
Mammals and birds can excrete hypertonic urine which is more concentrated than their blood. For this, an isotonic glomerular filtrate is first filtered into the Bowman's capsules of nephrons in kidneys. The tubules then reabsorb a large volume of water from the glomerular filtrate not accompanied by the reabsorption of proportionate amounts of solutes. This leaves the urine more concentrated than the blood which is very effective in reducing the urinary loss of water.
Refer the given figure of nephron.
Identify A, B, C and D and select the correct option regarding them
A-Glomerulus -a tuft of capillaries formed by afferent arteriole.
B-PCT-reabsorption of HCO3 and selective secretion of H and K+ occurs here.
C-DCT-almost all glucose, amino acids, water, Na, K and uric acid are absorbed here.
D-collecting duct-extends from the cortex of the kidney to the inner parts of medulla. Large amount of water is secreted in this region.
Which of the following is true for excretion in humans?
Glucose and amino acids are reabsorbed in PCT by simple diffusion.
OCT is impermeable to water.
Or an average, 25-30 gm of urea is excreted out per day.
Maximum reabsorption occurs in the loop of Henle.
Assertion: In proximal convoluted tubule glomerular filtrate becomes hypertonic to blood plasma.
Reason: HCO3- is absorbed only in the proximal convoluted tubule.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false
Assertion : While on going down the loop of Henle, the filtrate becomes hypotonic.
Reason : The descending limb of loop of Henle is impermeable to both water and electrolytes.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Which one of the following is correct regarding the excretion
Large amount of water from renal filtrate is reabsorbed in DCT and a less amount is reabsorbed by PCT.
The descending limb of loop of Henle is completely impermeable to salts.
Malpighian corpuscle is found in medulla region of kidney.
The colour of urine is pale yellow and is slightly alkaline in nature.
Which one of the following statements is correct with respect to salt water balance inside the body of living organisms?
when water is not available camels do not produce urine but store urea in tissues.
Salmon fish excretes lot of stored salt through gill membrane when in fresh water
Paramecium discharges concentrated salt solution by contractile vacuoles
The body fluids of fresh water animals are generally hypotonic to surrounding water
A person passes much urine and drinks much water but his blood glucose level is normal. This condition may be the result of:
a reduction in insulin secretion from pancreas
a reduction in vasopressin secretion from posterior pituitary
a fall in the glucose concentration in urine
an increase in secretion of glucagon
The amount of liquid filtered by glomeruli of kidney in 24 hours period is
170 L
100 L
200-250 cc
500-1000 cc
