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

What is the function of nephron?

  1. filters waste from blood

  2. Filters the nutrients we absorb

  3. Filters salt levels in the blood

  4. Filters the food we eat
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The nephron is the functional unit of the kidney. Its primary role is to filter waste products, excess salts, and water from the blood to produce urine, thereby maintaining homeostatic balance.

Multiple choice

Why is it important that the Loop of Henle passes into the Kidney's medulla?

  1. To allow waste move through by osmosis

  2. Establish an ion gradient so H2O can move through by osmosis

  3. ensure nutrients pass through

  4. establish an ion gradient
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The Loop of Henle descends into the highly concentrated (hypertonic) medulla of the kidney to establish and maintain an osmotic gradient. This gradient allows water to be reabsorbed from the collecting duct and descending limb via osmosis, concentrating the urine.

Multiple choice

Homeostasis in human body means

  1. Sugar balance

  2. Water balance

  3. Ionic balance

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

Homeostasis is the maintenance of a stable internal environment. While it encompasses sugar, water, and ionic balances, 'ionic balance' is often highlighted in specific physiological contexts, though the question is somewhat ambiguous.

Multiple choice

End stage renal disease belongs to which organ ?

  1. Brain

  2. Lungs

  3. Heart

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

Renal refers to anything related to the kidneys. Therefore, end-stage renal disease (ESRD) is the final, permanent stage of kidney failure, where the kidneys can no longer function on their own.

Multiple choice

In which part of a nephron does most reabsorption take place?

  1. loop of Henle

  2. distal convoluted tubule (DCT)

  3. proximal convoluted tubule (PCT)

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

The proximal convoluted tubule (PCT) is the site where the vast majority of reabsorption occurs in the nephron. It reabsorbs approximately 65% of the water, sodium, and potassium from the filtrate, along with virtually 100% of glucose and amino acids.

Multiple choice

In which order do filtrate materials pass through a nephron?

  1. glomerular capsule to PCT to loop of Henle to DCT

  2. DCT to loop of Henle to PCT to glomerular capsule
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Filtrate is formed in the glomerular (Bowman's) capsule and then flows sequentially through the proximal convoluted tubule (PCT), down and up the loop of Henle, and finally through the distal convoluted tubule (DCT) before entering the collecting duct.

Multiple choice

Which option lists the directional sequence of urine from the kidney?

  1. Kidney, ureter, urinary bladder, urethra, urethral opening.

  2. Kidney, urethra, ureter, urinary bladder, bladder opening.

  3. Kidney, urethral opening, ureter, urethra.

  4. Kidney, urethra, urinary bladder, ureter, urethral opening.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Urine is produced in the kidneys, travels down the ureters to be stored in the urinary bladder, and is then expelled through the urethra and out of the body via the urethral opening.

Multiple choice

Which sphincters open in order to allow urination from the urinary bladder?

  1. Internal and external urethral sphincters.

  2. Urethral and renal sphincters.

  3. Renal and prostatic sphincters.

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

Micturition (urination) requires the relaxation of both the internal urethral sphincter (which is involuntary and made of smooth muscle) and the external urethral sphincter (which is voluntary and made of skeletal muscle).

Multiple choice

What is the role of the urinary bladder?

  1. Temporary storage or urine

  2. Regulation of urinal output from the kidneys

  3. Recycling of essential salts back into the blood

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

The primary function of the urinary bladder is to serve as a temporary storage reservoir for urine before it is eliminated from the body. It does not regulate the kidneys' output or recycle salts back into the blood.

Multiple choice

What term is given to the “functional” units of the kidney?

  1. Nephrons

  2. Renals

  3. Bowman's capsules

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

Nephrons are the microscopic structural and functional units of the kidneys. Each kidney contains about one million nephrons, which perform the essential tasks of filtration, reabsorption, and secretion to form urine.

Multiple choice

In humans, the right kidney is positioned slightly lower than the left kidney. Why?

  1. The left kidney is crowded upwards by the liver.

  2. The right kidney is crowded downwards by the liver.

  3. Lung position effects the position of the left kidney.

  4. Both kidneys are at exactly the same level in humans.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The right kidney is positioned slightly lower than the left kidney because the large, heavy liver occupies a significant amount of space in the upper right quadrant of the abdominal cavity, pushing the right kidney downward.