Tag: excretion and osmoregulation

Questions Related to excretion and osmoregulation

Although the urinary bladder can hold as much as ............. ml of urine the desire for urination is usually experienced when
it contains about ......... ml.

zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. 500, 150

  2. 250, 100

  3. 150, 50

  4. 350, 100

Show answer
Correct Option: A
Explanation:

A completely full urinary bladder is capable of holding approximately 500-600 ml of fluid. The urge to urinate occurs when the bladder contains about 150-200 ml of urine. The urge to urinate is stimulated by expansion of of the bladder. As the bladder walls fill with urine and expand, stretch receptors are stimulated and the micturition reflex is triggered. The micturition reflex centre is located in the spinal cord. 

Urine output is reduced by

zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. Oxytocin

  2. ACTH

  3. LH

  4. Vasopressin

Show answer
Correct Option: D
Explanation:

The distal convoluted tubule (DCT) reacts to the amount of anti-diuretic hormone (ADH) or vasopressin in the blood. 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.

Voluntary response to distension of urinary bladder is

zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. Polyurea

  2. Micturition

  3. Diabetes mellitus

  4. Menstruation

Show answer
Correct Option: B
Explanation:

Micturition or urination is the process of expelling urine from the bladder. This act is also known as voiding of the bladder. The process of micturition is regulated by the nervous system and the muscles of the bladder and urethra. The urinary bladder can store around 350-400ml of urine before it expels it out.


So, the correct answer is 'Micturition'.

The shared terminal duct of the reproductive and urinary system in the human male is

zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. Urethra

  2. Ureter

  3. Vas deferens

  4. Vasa efferentia

Show answer
Correct Option: A
Explanation:

The shared terminal duct of the reproductive and urinary system in the human male is urethra. In human male urethra is urinogenital duct which carry both urine and sperm. 

Urine reaches the bladder from the kidneys through the urethra.

zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

Urine reaches the urinary bladder from the kidney to the urinary bladder via the tube-like structure called the' ureter'. While urethra is the channel that conveys the urine from the bladder to the exterior. 

So, the correct answer is 'False' 

Micturition is carried out by a reflex.
zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. True

  2. False

Show answer
Correct Option: A
Explanation:
In vertebrates, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord. This allows for faster reflex actions to occur by activating spinal motor neurons without the delay of routing signals through the brain.
The micturition reflex is ultimately generated from the level of the spinal cord after it receives reflexes from the pontine region in the brain. Once the bladder and the urethra receive the signals to empty the bladder, the two sphincters (external and internal) relax and the detrusor muscle causes the contractions of the bladder.
So, the correct option is 'True'.

Which of the following is the correct path taken by urine in our body?
(i) Kidneys

(ii) Ureters
(iii) Urethra
(iv) Urinary bladder

zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. $i, ii, iv, iii$

  2. $i, ii, iii, iv$

  3. $iv, iii, i, ii$

  4. $ii, iii, i, iv$

Show answer
Correct Option: A
Explanation:

Urine is formed in the kidney. From the kidney through two tubes called ureters the urine descends into the urinary bladder. From the urinary bladder, urine is excreted to outside through urethra. So the correct path taken by urine in our body is kidneys, ureters, urinary bladder, urethra.

So, the correct answer id 'Option A'.

Angiotensin - II causes 

zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. Contraction of vascular musculature

  2. Release of aldosterone from cortex

  3. Dilation of blood vessels

  4. Both A and B

Show answer
Correct Option: D
Explanation:

Angiotensin is a peptide hormone that causes vasoconstriction and an increase in blood pressure. It is part of the renin–angiotensin system, which regulates blood pressure. Angiotensin also stimulates the release of aldosterone from the adrenal cortex to promote sodium retention by the kidneys.


So the correct option is 'Both A & B'.

In micturition,

zoology excretion and osmoregulation micturition urine and urine formation urine formation

  1. Urethral sphincter contract

  2. Uterus contract

  3. Urethral sphincter relaxes

  4. None of these

Show answer
Correct Option: C
Explanation:

During micturition, parasympathetic stimulation causes the detrusor muscle to contract and the internal urethral sphincter to relax. The external urethral sphincter (sphincter urethrae) is under somatic control and is consciously relaxed during micturition. 

So, the correct option is 'Urethra relaxes'.

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. There will be no micturition

  2. Urine will continue to collect normally in bladder

  3. Micturition will continue

  4. Urine will not collect in the bladder

Show answer
Correct Option: A