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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

Question 1 of 10Score: 0

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

Full Question List & Answer Key

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

1. 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.

2. Where are osmoreceptors responsible for detecting changes in blood osmotic pressure located?

  1. A. Carotid sinus
  2. B. Medulla oblongata
  3. C. Hypothalamus
  4. D. Adrenal cortex
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Answer: C

Osmoreceptors in the hypothalamus sense changes in blood solute concentration and adjust thirst and ADH release accordingly.

3. 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.

4. What is the primary action of glucagon when blood glucose levels fall below normal?

  1. A. Stimulating liver cells to convert glycogen into glucose
  2. B. Increasing rate of glucose uptake in skeletal muscle cells
  3. C. Promoting storage of excess glucose into fat tissue
  4. D. Inhibiting gluconeogenesis in liver tissues
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Answer: A

Glucagon secreted by pancreatic alpha cells accelerates glycogenolysis (breakdown of glycogen to glucose) in the liver to elevate blood glucose.

5. 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.

6. 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.

7. 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.

8. 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.

9. In hemodialysis, why does the dialysis fluid flow in the opposite direction to the patient's blood (counter-current flow)?

  1. A. To maintain a concentration gradient along the entire length of the membrane for efficient waste removal
  2. B. To prevent blood clot formation inside the artificial dialyzer tubing
  3. C. To increase blood pressure before it re-enters the vein
  4. D. To force red blood cells across the semi-permeable membrane
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Answer: A

Counter-current flow maximizes the concentration gradient between blood and dialysis fluid, ensuring maximum diffusion of urea and excess solutes out of blood.

10. What condition can result from crystallized mineral deposits forming inside the renal pelvis or urinary tract?

  1. A. Diabetes mellitus
  2. B. Kidney stones
  3. C. Diabetes insipidus
  4. D. Nephrotic hypertension
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Answer: B

Kidney stones (urolithiasis) are hard insoluble mineral crystals (such as calcium oxalate) that form in urine when fluid intake is low.

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