which part of the nephron is closest to the collecting duct

ATI RN

ATI Anatomy and Physiology

1. 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.

2. Homeostasis is the body's maintenance of a stable internal environment.

A. TRUE
B. FALSE
C. Not Sure
D. None of the above

Correct answer: A

Rationale: Homeostasis refers to the body's ability to maintain a stable internal environment despite external changes. It involves processes that regulate various physiological factors such as temperature, pH, and blood sugar levels within a narrow range. This ensures that the body's cells can function optimally. Therefore, the correct answer is True. Choices B, C, and D are incorrect because homeostasis aims to maintain stability, not instability, in the internal environment.

3. When does cell death first occur?

A. At age 60.
B. At age 50.
C. At puberty.
D. In the fetus.

Correct answer: D

Rationale: Cell death, also known as apoptosis, first occurs during fetal development when specific cells are programmed to die. This process is essential for shaping and organizing tissues and organs. Choices A, B, and C are incorrect because cell death begins much earlier, during fetal development, rather than later in life or at puberty. Understanding the timing of cell death in different stages of life is crucial in developmental biology.

4. 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.

5. Which of the following may indicate hypersecretion of thyroid hormone?

A. weight loss
B. Bradycardia
C. cold intolerance
D. lethargy

Correct answer: A

Rationale: Weight loss is a common symptom of hyperthyroidism, which is characterized by an excess secretion of thyroid hormone. This increased metabolic rate can lead to weight loss despite normal or increased appetite. Bradycardia (slow heart rate), cold intolerance, and lethargy are more commonly associated with hypothyroidism, where there is an insufficient production of thyroid hormone. Therefore, choices B, C, and D are incorrect in the context of hypersecretion of thyroid hormone.