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
-
Intestines
-
Brain
-
Nose
-
Kidney
D
Correct answer
Explanation
The kidneys are the body's primary filtration system, removing waste products and excess substances from blood through millions of tiny filtering units called nephrons. Each kidney processes about 200 quarts of blood daily, producing about 2 quarts of waste fluid (urine). The kidneys also regulate blood pressure, electrolyte balance, and red blood cell production.
-
400 gallons
-
300 gallons
-
500 gallons
-
200 gallons
-
Nephrologist
-
Dermatologist
-
Obstetrician
-
Urologist
D
Correct answer
Explanation
A urologist specializes in treating conditions of the urinary tract, including the bladder. The other specialists listed deal with different medical areas: skin, kidneys, and pregnancy.
-
Nephrologist
-
Rheumatologist
-
Endocrinologist
-
Dermatologist
A
Correct answer
Explanation
A nephrologist is a kidney specialist who treats kidney diseases and disorders. The prefix 'nephr-' relates to kidneys. Other specialists listed treat joints, hormones, or skin.
-
Kidney failure
-
Heart weakness
-
Brain diseases
-
None of these
A
Correct answer
Explanation
Dialysis is an artificial process that performs the kidney's primary function of filtering waste products, excess salts, and fluids from the blood when kidneys fail. It is the definitive treatment for end-stage renal disease and acute kidney failure. The procedure has no therapeutic effect on heart weakness or brain diseases.
-
Nostrils
-
Lungs
-
Kidney
-
Liver
C
Correct answer
Explanation
Nephritis is the inflammation of the kidneys, derived from the Greek word 'nephros' meaning kidney. This condition can affect kidney function and may be caused by infections, autoimmune diseases, or toxins. The kidneys filter blood and remove waste from the body.
A
Correct answer
Explanation
Incontinence is indeed defined as the lack of voluntary control over excretory functions, which can affect bladder or bowel control. This is the standard medical definition.
-
phosphate
-
magnesium
-
sodium
-
bicarbonate
D
Correct answer
Explanation
Concentration of bicarbonate ions is not controlled by PTH. Its concentration depends on the buffering capacity of blood in the form of carbonate bicarbonate buffer
-
Baroreceptor
-
Chemoreceptor
-
Interoceptor
-
Osmoreceptor
D
Correct answer
Explanation
It is a sensory receptor mainly found in the hypothalamus.
-
The renal cortex lies inside the medulla.
-
The left kidney lies lower than the right kidney.
-
The renal veins drain directly into the inferior vena cava.
-
The link between the kidney and the bladder is the urethra.
-
The renal cortex contains selected glomeruli.
C
Correct answer
Explanation
Both kidneys receive an arterial supply directly from the aorta and the renal veins drain directly into the inferior vena cava.
-
Acid can be excreted as NH4+ ions.
-
Acid excretion mainly occurs in the early nephron.
-
In the distal nephron, secreted hydrogen ions mainly contribute to bicarbonate reabsorption.
-
Sodium phosphate is an urinary base.
-
Human urine is usually alkaline in nature.
A
Correct answer
Explanation
When hydrogen ions are secreted by the tubules, they can combine with NH3 to form NH4+ and so can be excreted as NH4+.
-
Bicarbonate ions are freely filtered in the glomerulus.
-
Bicarbonate ions are reabsorbed in the distal tubule.
-
Carbonic anhydrase catalyses the formation of bicarbonate ions.
-
The secretion of hydrogen ions results in bicarbonate reabsorption.
-
If required, the bicarbonate ions can function as a base in the kidneys.
B
Correct answer
Explanation
The major site of reabsorption of bicarbonate ions is the proximal tubule.
-
Acid can be excreted as NH4+ ions.
-
Acid excretion mainly occurs in the early nephron.
-
In the distal nephron, secreted hydrogen ions mainly contribute to bicarbonate reabsorption.
-
Sodium phosphate is a urinary base.
-
Human urine is usually alkaline in nature.
A
Correct answer
Explanation
When hydrogen ions are secreted by the tubules, they can combine with NH3 to form NH4+ and excreted as NH4+.
-
Tubular secretion is more important than tubular reabsorption for most of the drugs.
-
Drug molecules, which are bound to proteins are not filtered.
-
Lipid soluble drugs require special transporter molecules to cross cell membranes.
-
The proximal tubule is a site of drug secretion.
-
A charge on a drug favours water solubility.
C
Correct answer
Explanation
Lipid soluble drugs and other lipid soluble substances are able to diffuse across the lipid plasma membrane of cells without special transporter molecules.
-
Calcium is reabsorbed but not secreted in the tubules.
-
Phosphate is secreted but not reabsorbed in the tubules.
-
Phosphate is reabsorbed with sodium in the proximal tubule.
-
Calbindins can transport calcium across tubular cells.
-
The reabsorption of calcium and phosphate ions takes place in the proximal tubules.
B
Correct answer
Explanation
There is no secretion of phosphate and is reabsorbed along the nephron. There is a limit to the amount of phosphate that can be absorbed and if this limit exceeds, the excess phosphate remains in the tubular fluid and is excreted in the urine.