Biology

Human Excretion and Kidney Physiology

1,152 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 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

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

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

  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
Reveal answer Fill a bubble to check yourself
D Correct answer
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'.
Multiple choice zoology excretion and osmoregulation micturition urine and urine formation urine formation

The urine is

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

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

Out of the following, choose the correct path of urine in our body.

  1. Kidney ---> ureter ---> urethra ---> urinary bladder

  2. Kidney ---> urinary bladder ---> urethra ---> ureter

  3. Kidney ---> ureter ---> urinary bladder ---> urethra

  4. Urinary bladder ---> kidney ---> ureter ---> urethra
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The urinary system consists of the kidneys, ureters, urinary bladder, and urethra. The kidneys filter the blood to remove wastes and produce urine. The ureters, urinary bladder, and urethra together form the urinary tract, which acts as a plumbing system to drain urine from the kidneys, store it, and then release it during urination, respectively. Besides filtering and eliminating wastes from the body, the urinary system also maintains the homeostasis of water, ions, pH, blood pressure, calcium and RBCs.

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

Choose the correct answer from the alternatives given.
The hormone that controls the output of urine is:

  1. epinephrine

  2. vasopressin

  3. aldosterone

  4. oxytocin
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

(A) Epinephrine is related to the adrenal gland and is released during stress or emergency situation. 

(B) Vasopressin is stimulated when there is excessive loss of fluid from the body. This facilitates water reabsorption from the latter parts of the tubule, thereby preventing diuresis. 
(C) Aldosterone Acts mainly at the renal tubules and stimulates the reabsorption of Na+ and water and excretion of K+ and phosphate ions.
(D) Oxytocin acts on the smooth muscles of our body and stimulates their contraction.
So the correct answer is vasopressin.

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

In humans, water is

  1. found in the glomerular filtrate

  2. reabsorbed from the nephron

  3. in the urine

  4. all of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

  • In nephrons, potassium ion, sodium chloride, calcium ion, amino acids, glucose, bicarbonate ion, and water are reabsorbed back into the bloodstream. 
  • The glomerular filtrate contains a lot of water, but also important molecules like glucose, amino acids, salts, and excretory material, urea.
  • Urine is an aqueous solution of greater than 95% water. Other constituents include urea, chloride, sodium, potassium, creatinine and other dissolved ions, and inorganic and organic compounds. Urea is a non-toxic molecule made of toxic ammonia and carbon dioxide.

So, the correct answer is 'all of the above
'.

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

Consider the following statements each with two blanks.


(i) Annelids have (1) and insects have (2) for excretion.
(ii) Blood enters the glomerulus via (3) arteriole and leaves via (4) arteriole.
(iii) During micturition, the urinary bladder (5) and urethral sphincters (6).
Which one of the following options correctly fills the blanks in any two of the above statements?

  1. $(1)$-Malphigian tubules, $(2)$-Flame cells, $(5)$- Contracts, $(6)$- Relax
  2. $(3)$-Afferent, $(4)$-Efferent, $(5)$- Contracts, $(6)$- Relax
  3. $(1)$- Nephridia, $(2)$-Malpighian tubules, $(5)$- Relaxes, $(6)$- Contract
  4. $(3)$- Efferent, $(4)$-Afferent, $(5)$- Relaxes, $(6)$- Contract
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

  1. Annelids have nephridia and insects have malphaghian tubules for excretion.
  2. Blood enters the glomerulus via afferent arteriole and leaves via efferent arteriole.
  3. During micturition, the urinary bladder contract and urethral sphincters relax to let the urine pass out from the body.
So, the correct answer is (B);

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

Consider the  following four statements (i) - (iv) and select the option that correctly identifies the true $(T)$ and false $(F)$ ones .


(i) Micutrition is carried out by a reflex.
(ii) ADH helps in water elimination making the urine hypotonic.
(iii) Protein-free fluid is filtered from blood plasma into the Bowman's capsule.
(iv) Glucose is actively reabsorbed in the proximal convoluted tubule.

  1. (i) $T$ , (ii) $F$ , (iii) $T$, (iv) $T$
  2. (i) $T$ , (ii) $T$ , (iii) $F$, (iv) $F$
  3. (i) $F$ , (ii) $F$ , (iii) $F$, (iv) $T$
  4. (i) $F$ , (ii) $T$ , (iii) $F$, (iv) $T$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Micturition is carried out by the parasympathetic reflexes.
  • ADH hormone helps in the reabsorption of water making the urine hypertonic.
  • All the large proteins, cells remain in the blood and pass into the tubule due to the presence of bowman's capsule.
  • Glucose, and other important ions get reabsorbed from the PCT.
  • Thus, the correct answer is 'T, F, T, T'.