Tag: excretion and osmoregulation

Questions Related to excretion and osmoregulation

Which are relaxed during micturition?
(i) Internal urethral sphincter
(ii) External urethral sphincter
(iii) Renal pelvis
(iv) Muscles of bladder.

zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. Only (i) and (iii)

  2. Only (i), (ii) and (iii)

  3. Only (i) and (ii)

  4. (i), (ii), (iii) and (iv)

Show answer
Correct Option: A

All the following statements about micturition are correct but one is wrong, which one is wrong?

zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. Micturition is under the control of parasympathetic nervous system

  2. During this process detrusor muscles of the bladder contract and internal sphincter muscles elax

  3. During micturition external sphincter muscles also relax to void out urine

  4. During micturition the sympathetic nervous system causes relaxation of detrusor muscles and constriction of internal sphincter

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Correct Option: A

Which of the following factors would cause an increased volume of urine production in a man?

zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. A humid day

  2. More intake of water than usual

  3. Drinking a large quantity of strong salt water

  4. All of the above

Show answer
Correct Option: D
Explanation:

On a humid day the water loss due to sweating will be less. If a man consumed large amounts of water or salt then the body will try to excrete out extra water and salt by increasing the urine output. In this condition the amount of ADH secretion is low and the water reabsorption in the DCT is low, making the urine hypotonic.

Why do we pass more urine in wet and cold season?

zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. Impairment of water absorption by nephrons.

  2. Kidney becomes more active.

  3. Sweating is much decreased.

  4. ADH secretion is increased.

Show answer
Correct Option: C
Explanation:

When the weather is hot, our body system tries to keep our body cool by evaporating the water along with unwanted things (sweating) through the skin in the form of perspiration. So, skin helps the kidney by sharing its work of cleaning the body in hot weather. In cold conditions, as sweating is much decreased, there is no perspiration and the kidney has to bear the entire burden of excretion and hence we urinate frequently.

The normal range of urinary output per day in human adults is

zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. 50 ml

  2. 10 ml

  3. 400-2000 ml

  4. 200 ml

Show answer
Correct Option: C
Explanation:

The waste products from the blood are removed by the kidneys in the form of urine. This is done by filtering of the blood. In human adults, the normal range of urinary output is between 400 to 2000 ml daily. The amount of urine produced by the body depends on the health of the person.

Urine is stored in

zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. Kidneys

  2. Ureter

  3. Urethra

  4. None of the above

Show answer
Correct Option: D
Explanation:

Urine is a liquid created by the body in the kidneys. It is stored in the bladder and comes out of the human body through the urethra, a tube which leads from the bladder to the urethral meatus, at the tip of the penis (men) or the vulva (women). Urinating is how the body gets rid of unwanted or unneeded substances in the blood. Urine is the liquid that these substances are put in. After the blood has circulated through the body, its composition has changed, because some substances in the blood have been absorbed by the body and because the body has released other substances into the blood. 

So, the correct answer is option D.

What will happen if the stretch receptors of the urinary bladder wall are totally removed?

zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. Urine will not collect in the bladder

  2. Micturition will continue

  3. Urine will continue to collect in the bladder

  4. There will be no micturition

Show answer
Correct Option: C,D
Explanation:
  • Stretch receptors are responsible for sending the signal to the brain when the urinary bladder is filled to its maximum capacity if they are removed urine will collect normally in the bladder and may overflow after a point.
  • Stretch receptors are responsible for sending the signal to the brain when the urinary bladder is filled to its maximum capacity if they are removed two things will happen:

1- urine will continue to get collected in the bladder,
2- since there is no receptor to stop urine collection in the bladder and remove the already present urine, there will be no micturition.

So, the correct answer is 'C, D'.

The urine is

zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. Hypotonic to blood and isotonic to medullary fluid

  2. Hypertonic to blood and isotonic to medullary fluid

  3. Isotonic to blood and hypotonic to medullary fluid

  4. Isotonic to blood and hypertonic to medullary fluid

Show answer
Correct Option: B
Explanation:

Urine becomes hypertonic because of the loop of Henle and the collecting duct.  Salt passively diffuses out of the lower portion of the ascending limb. The upper part of ascending limb actively transports salt into the tissue of the renal medulla. Urea leaks from the lower portion of collecting duct and contributes to a high solute concentration. Water leaves descending limb of the loop of Henle, returning to the blood. Hence, urine is hypertonic to blood and isotonic to medullary plasma.

Which of the following is responsible for excretion of dilute urine?

zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. More secretion of insulin

  2. Less secretion of vasopressin

  3. More secretion of aldosterone

  4. Less secretion of glucagon

Show answer
Correct Option: B
Explanation:

The more ADH is present in the blood, the more water is reabsorbed into it. This happens because the presence of ADH in the blood causes the cells in the last section of the DCT to become more permeable to water, therefore they allow more water to pass from the tubular fluid back into the blood. This results in more concentrated urine.

Vasopressin is related with

zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. Dilution of urine

  2. Quick digestion

  3. Concentration of urine

  4. Slow heart beat

Show answer
Correct Option: C
Explanation:

The more ADH is present in the blood, the more water is reabsorbed into it. This happens because the presence of ADH in the blood causes the cells in the DCT to become more permeable to water, therefore they allow more water to pass from the tubular fluid back into the blood. This results in more concentrated urine.