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Quiz Chapter 13: Homeostasis and the Human Urinary System

10 questions · Form 4 Biology Bab 13: Homeostasis and the Human Urinary System

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Full Question List & Answer Key

Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.

1. Where does 100% of useful filtered nutrients, such as glucose and amino acids, get reabsorbed back into the bloodstream under normal healthy conditions?

  1. A. Descending limb of Loop of Henle
  2. B. Proximal convoluted tubule
  3. C. Distal convoluted tubule
  4. D. Collecting duct
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Answer: B

The proximal convoluted tubule actively reabsorbs all filtered glucose and amino acids back into the surrounding peritubular capillaries.

2. How do cutaneous blood vessels respond when the body's core temperature drops below normal?

  1. A. Vasodilation occurs to bring more blood to skin surface.
  2. B. Vasoconstriction occurs to restrict blood flow near skin surface and lessen heat loss.
  3. C. Sweat glands increase secretion to trap warm air.
  4. D. Arterioles dilate to lower systemic blood pressure.
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Answer: B

Vasoconstriction of skin arterioles narrows blood vessels, reducing cutaneous blood flow and minimizing radiation heat loss.

3. Diabetes insipidus is a disorder caused by an inability of the body to produce or respond to which hormone?

  1. A. Insulin
  2. B. Antidiuretic hormone (ADH)
  3. C. Glucagon
  4. D. Aldosterone
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Answer: B

Deficiency of ADH prevents water reabsorption in distal tubules, causing Diabetes Insipidus characterized by excessive excretion of dilute urine.

4. Which nephron segment connects the proximal convoluted tubule directly to the distal convoluted tubule?

  1. A. Bowman's capsule
  2. B. Glomerulus
  3. C. Loop of Henle
  4. D. Collecting duct
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Answer: C

The hairpin-shaped Loop of Henle extends down into the renal medulla, connecting proximal and distal convoluted tubules.

5. Which brain structure acts as the central control organ for monitoring and regulating human body temperature?

  1. A. Cerebrum
  2. B. Medulla oblongata
  3. C. Hypothalamus
  4. D. Pituitary gland
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Answer: C

The hypothalamus acts as the body's thermostat, receiving temperature signals from thermoreceptors to trigger compensatory heat loss or heat retention mechanisms.

6. Which of the following substances is actively secreted from peritubular capillaries into the renal tubule to help regulate blood pH?

  1. A. Hydrogen ions (H⁺)
  2. B. Glucose
  3. C. Plasma proteins
  4. D. Red blood cells
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Answer: A

Excess hydrogen ions (H+) and ammonium ions are actively secreted into renal tubules during the secretion phase to remove excess acidity and maintain blood pH.

7. When a person consumes a large volume of water, what change occurs in ADH secretion and the resulting urine produced?

  1. A. ADH secretion increases; small volume of concentrated urine
  2. B. ADH secretion decreases; large volume of dilute urine
  3. C. ADH secretion increases; large volume of dilute urine
  4. D. ADH secretion decreases; small volume of concentrated urine
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Answer: B

Excess water lowers blood osmotic pressure, causing the posterior pituitary to release less ADH. The distal tubule becomes less permeable to water, leading to a large volume of dilute urine.

8. What primary mechanism allows ultrafiltration to occur within the glomerulus of the nephron?

  1. A. High hydrostatic pressure caused by the afferent arteriole having a larger diameter than the efferent arteriole
  2. B. Active transport of blood proteins across the glomerular membrane
  3. C. Low osmotic pressure in the peritubular capillary network
  4. D. Selective pinocytosis by podocyte epithelial cells
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Answer: A

The difference in diameter between the wider afferent arteriole and narrower efferent arteriole creates high hydrostatic pressure in glomerular capillaries, forcing fluid into Bowman's capsule.

9. Which hormone is secreted by the beta (β) cells of the pancreas when blood glucose levels exceed the normal range?

  1. A. Glucagon
  2. B. Insulin
  3. C. Adrenaline
  4. D. Thyroxine
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Answer: B

Beta cells of the Islets of Langerhans secrete insulin to lower elevated blood glucose by promoting glucose uptake and glycogenesis.

10. A rise in carbon dioxide concentration ($pCO_2$) in the blood leads directly to which physiological change?

  1. A. Increase in blood pH (alkalosis)
  2. B. Decrease in blood pH (acidosis)
  3. C. Inhibition of the respiratory centre
  4. D. Vasoconstriction of pulmonary capillaries
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Answer: B

CO2 reacts with water to form carbonic acid ($H_2CO_3$), which dissociates into $H^+$ ions, lowering blood pH.

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