Biology

Human Excretion and Kidney Physiology

1,215 Questions

Human excretion and kidney physiology questions test your understanding of the excretory system, including the role of renal tubules and glomerular filtration. You will also find topics on urine formation, body water absorption, and excretory products. This section is vital for medical and general science exam preparation.

Glomerular filtrationRenal tubule absorptionExcretory productsRole of sodium ionsHuman excretory system

Human Excretion and Kidney Physiology Questions

Multiple choice zoology the endocrine system adrenal gland thymus and adrenal gland adrenal glands

In urinary, system, aldosterone takes part in retention (reabsorption) of

  1. $Ca^{2+}$
  2. $ K^+$
  3. $Na^+$

  4. Water
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In urinary, system, aldosterone takes part in retention of sodium ions. The ADH released by posterior pituitary triggers the release of aldosterone which increases the concentration of sodium ions in the blood. The increased salt concentration in the blood increases the blood osmotic potential which further increases reabsorption of water and incraeses the blood volume and blood pressure.

So, the correct answer is 'Na$^+$'.

Multiple choice zoology the endocrine system adrenal gland thymus and adrenal gland adrenal glands

In urinary system, aldosterone takes part in retention (reabsorption) of 

  1. $K^{+}$
  2. $Na^{+}$

  3. Water

  4. both (b) and (c)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Aldosterone is the principle mineralocorticoid. It increases sodium (Na$^{+}$) and water resorption by the kidney in exchange for potassium or hydrogen. 

So, the correct option is 'both (b) and (c)'.

Multiple choice zoology endocrine system and chemical co-ordination adrenal gland thymus and adrenal gland adrenal glands

Concentration of sodium and chloride ions is lowest

  1. Near the cortex

  2. Deep in medulla

  3. In interstitial fluid

  4. In middle of Henle's loop
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Osmolarity in the cortex region of the kidney is the lowest. Hence, the concentration of sodium and chloride ions is the lowest in the region near cortex.

So, the correct option is 'Near the cortex'.

Multiple choice evs circulation of blood blood transfusion transfusion of blood blood and organ donation

Glomerular filtration rate would be decreased by?

  1. Construction of the efferent arteriole

  2. An increase in afferent arteriolar pressure

  3. Compression of the renal capsule

  4. An increase in renal blood flow
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Constriction of the afferent arteriole would increase the pressure in the afferent arteriole. This would decrease the blood flow into the glomerulus and hence, the glomerular filtration rate decreases. This is due to the decrease in the glomerular hydrostatic pressure.
So, the correct answer is 'An increase in afferent arteriolar pressure'.

Multiple choice zoology excretion and osmoregulation micturition urine and urine formation urine formation

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

  1. 500, 150

  2. 250, 100

  3. 150, 50

  4. 350, 100
Reveal answer Fill a bubble to check yourself
A Correct answer
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. 

Multiple choice zoology excretion and osmoregulation micturition urine and urine formation urine formation

Urine output is reduced by

  1. Oxytocin

  2. ACTH

  3. LH

  4. Vasopressin
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

Multiple choice zoology excretion and osmoregulation micturition urine and urine formation urine formation

Voluntary response to distension of urinary bladder is

  1. Polyurea

  2. Micturition

  3. Diabetes mellitus

  4. Menstruation
Reveal answer Fill a bubble to check yourself
B Correct answer
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'.

Multiple choice zoology excretion and osmoregulation micturition urine and urine formation urine formation

Urine reaches the bladder from the kidneys through the urethra.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
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' 

Multiple choice zoology excretion and osmoregulation micturition urine and urine formation urine formation

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

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

  1. $i, ii, iv, iii$
  2. $i, ii, iii, iv$
  3. $iv, iii, i, ii$
  4. $ii, iii, i, iv$
Reveal answer Fill a bubble to check yourself
A Correct answer
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'.

Multiple choice zoology excretion and osmoregulation micturition urine and urine formation urine formation

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

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Stretch receptors in the bladder wall detect fullness and trigger the micturition reflex. If these are removed, the brain does not receive the signal to void, preventing micturition.

Multiple choice zoology excretion and osmoregulation micturition urine and urine formation urine formation

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

  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
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

Multiple choice zoology excretion and osmoregulation micturition urine and urine formation urine formation

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

  1. Impairment of water absorption by nephrons.

  2. Kidney becomes more active.

  3. Sweating is much decreased.

  4. ADH secretion is increased.
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

Multiple choice zoology excretion and osmoregulation micturition urine and urine formation urine formation

Urine is stored in

  1. Kidneys

  2. Ureter

  3. Urethra

  4. None of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

Multiple choice zoology excretion and osmoregulation micturition urine and urine formation urine formation

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

  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
Reveal answer Fill a bubble to check yourself
C,D Correct answer
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'.