Which part of the nephron is closest to the collecting duct?
- A. Distal convoluted tubule (DCT)
- B. Bowman's Capsule
- C. Afferent Arteriole
- D. Proximal Convoluted Tubule (PCT)
Correct Answer: A
Rationale: The correct answer is the Distal convoluted tubule (DCT). The DCT is the part of the nephron closest to the collecting duct, where the final adjustments to electrolyte and fluid balance are made. Bowman's Capsule is located at the beginning of the nephron, where filtration of blood occurs. The Afferent Arteriole brings blood to the glomerulus for filtration. The Proximal Convoluted Tubule (PCT) is situated after the Bowman's Capsule and is not the part closest to the collecting duct.
You may also like to solve these questions
Which of the following substances is involved in the destruction of ingested pathogens?
- A. lymphatic fluid
- B. stomach acid
- C. bicarbonate
- D. lipase
Correct Answer: B
Rationale: The correct answer is stomach acid. Stomach acid, also known as gastric acid, plays a crucial role in destroying ingested pathogens due to its high acidity. The low pH of stomach acid helps to kill bacteria and other pathogens that may be present in the food we consume. Lymphatic fluid is involved in immune function and fat absorption, not pathogen destruction. Bicarbonate is a base that neutralizes stomach acid to prevent damage to the stomach lining. Lipase is an enzyme that aids in the digestion of fats but is not involved in pathogen destruction.
Which of the following is the measurement of the percentage of red blood cells in whole blood?
- A. Hematocrit
- B. Hemoglobin
- C. Mean corpuscular volume
- D. Reticulocyte count
Correct Answer: A
Rationale: The correct answer is 'Hematocrit.' Hematocrit is the measurement of the percentage of red blood cells in whole blood. It is used to diagnose conditions such as anemia and dehydration. Choice B, 'Hemoglobin,' measures the amount of hemoglobin in the blood, not the percentage of red blood cells. Choice C, 'Mean corpuscular volume,' measures the average volume of a red blood cell, not the percentage of red blood cells. Choice D, 'Reticulocyte count,' measures the percentage of young red blood cells in the blood, not the percentage of red blood cells.
Which of the following is produced by the prostate gland?
- A. testosterone
- B. fluid to lubricate the head of the penis
- C. substance to enhance sperm mobility
- D. Gonadotrophin-releasing hormone
Correct Answer: B
Rationale: The correct answer is 'fluid to lubricate the head of the penis.' The prostate gland produces a milky fluid that makes up part of the seminal fluid, which helps to nourish and transport sperm. Testosterone is produced mainly by the testes, not the prostate gland. While the prostate gland does contribute to sperm mobility, its primary function is to produce the fluid that lubricates the penis during ejaculation. Gonadotrophin-releasing hormone is produced by the hypothalamus and regulates the release of hormones from the pituitary gland.
Testosterone production is regulated by which of the following glands?
- A. Pineal
- B. Thymus
- C. Parathyroid
- D. Pituitary
Correct Answer: D
Rationale: Testosterone production is regulated by the pituitary gland. The pituitary gland secretes luteinizing hormone (LH), which stimulates the Leydig cells in the testes to produce testosterone. This hormone is not regulated by the Pineal, Thymus, or Parathyroid glands. The Pineal gland is responsible for secreting melatonin, the Thymus gland is involved in immune function, and the Parathyroid glands regulate calcium levels in the blood.
Lowering the hand by straightening the elbow affects which of the following muscles?
- A. biceps brachii
- B. triceps brachii
- C. brachialis
- D. brachioradialis
Correct Answer: B
Rationale: Lowering the hand by straightening the elbow is the action of extending the forearm, which is primarily done by the triceps brachii muscle. The triceps brachii is the main extensor muscle of the elbow joint. The biceps brachii is responsible for flexing the elbow, not extending it, making it an incorrect choice. Brachialis is a strong elbow flexor, and brachioradialis helps in flexing the elbow and pronating the forearm, so they are not the primary muscles involved in straightening the elbow.