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 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

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

  1. More secretion of insulin

  2. Less secretion of vasopressin

  3. More secretion of aldosterone

  4. Less secretion of glucagon
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

Vasopressin is related with

  1. Dilution of urine

  2. Quick digestion

  3. Concentration of urine

  4. Slow heart beat
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

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

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

The excretory waste materials eliminated by kidney as aqueous solution is called as

  1. Urine

  2. Urea

  3. Uric acid

  4. Ammonia
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mammals, many terrestrial amphibians mainly excrete urea and are called ureotelic animals. The urea is excreted in aqueous solution in more liquified form, called urine. Urine formation involves three main processes namely, glomerular filtration, reabsorption and secretion, that takes place in different parts of the nephron.

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

The outline of principal events of urination is given below in random manner. 
(i) Stretch receptors on the wall of urinary bladder send signals to the CNS.
(ii) The bladder fills with urine and becomes distended. 
(iii) Micturition.
(iv) CNS passes on motor messages to initiate the contraction of smooth muscles of bladder and simultaneous relaxation of urethral sphincter.

  1. (i) $\rightarrow$ (ii) $\rightarrow$ (iii) $\rightarrow$ (iv)
  2. (iv) $\rightarrow$ (iii) $\rightarrow$ (ii) $\rightarrow$ (i)
  3. (ii) $\rightarrow$ (i) $\rightarrow$ (iv) $\rightarrow$ (iii)
  4. (iii) $\rightarrow$ (ii) $\rightarrow$ (i) $\rightarrow$ (iv)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Process of urination involves these following steps: - 

  1.  Filling of the urinary bladder with the urine and after filling, the bladder becomes distended.
  2. The filled bladder stretches the receptors present on its wall and send signals to the CNS.
  3. After receiving the signal the CNS passes the signal to initiate the contraction of smooth muscles of bladder and simultaneous relaxation of the urethral sphincter.
  4. Ultimately after the contraction of detrusor muscles of the urinary bladder and relaxation of the sphincter causes Micturition.
So, the correct answer is (ii) → (i) → (iv) → (iii).

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

Urine leaves the kidney as

  1. Water

  2. Blood

  3. Interstitial fluid

  4. Tissue fluid
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Urine is a liquid excretory product of the body excreted by the kidneys through a process called urination (or micturition) and excreted through the urethra. Urine contains urea and water. A urea is toxic it needs water to be excreted from the body.

So, the correct answer is option A.

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

Urine is stored in

  1. Ureter

  2. Kidney

  3. Urinary bladder

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

The blood is filtered by the kidney and the urine is formed. Urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. It is a hollow muscular, and distensible (or elastic) organ. Urine enters the bladder via the ureters and exits via the urethra. 

So, the correct answer is option C.

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

Largest amounts of nitrogen are excreted through

  1. Sweat

  2. Faeces

  3. Breath

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

The urinary system is involved in the excretion of nitrogenous waste products such as urea, uric acid or ammonia. The excretion of nitrogenous waste from animals is important because if it is allowed to build up, it can prove toxic. The waste product is formed due to the breakdown of the amino acids.

So, the correct answer is option D.

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

The filling of the urinary bladder essentially requires

  1. Relaxation of detrusor muscle

  2. Contraction of internal sphinet

  3. Stimulation of sympathetic nerve

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

The muscular part of the bladder wall is called the detrusor muscle. The internal and external sphincter muscles surround the bladder neck and the urethra. While the bladder is filling, the detrusor muscle is relaxed so the bladder wall can expand, and the sphincter muscles are contracted to keep the urethra closed. Sympathetic stimulation is predominant during bladder filling, and the parasympathetic causes emptying. Thus, option D is correct and other options are wrong.

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

The feeling of fullness sensation of urine is marked if the volume of urine increases upto

  1. 200 c.c

  2. 300 c.c

  3. 600 c.c

  4. 1000 c.c
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The feeling of fullness sensation of urine is marked if the volume of urine increases up to 600 c.c.

Urination is the release of urine from the urinary bladder through the urethra to the urinary meatus outside of the body. It is also known medically as micturition.
Physiologically, urination involves coordination between the central, autonomic, and somatic nervous systems.In the adult, the volume of urine in the bladder that normally initiates a reflex contraction is about 300–400 millilitres.
Therefore, the correct answer is option C.