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 exists if concentrations of water, nutrients, and oxygen in the body and heat and pressure __________.
- A. decrease steadily
- B. remain within certain limited ranges
- C. increase when the body is stressed
- D. fluctuate greatly between very high and low values
Correct answer: B
Rationale: Homeostasis is the body's ability to maintain stable internal conditions despite external changes. To achieve this balance, concentrations of essential substances must remain within specific ranges. Choice A is incorrect because decreasing concentrations would not maintain stability. Choice C is incorrect as increasing concentrations when the body is stressed would disrupt homeostasis. Choice D is incorrect as fluctuating greatly between high and low values would also not support the body's stability. Therefore, the correct answer is B, as it aligns with the concept of homeostasis by emphasizing the need for stability within certain limits.
3. Which of the following electrolytes plays an essential role in the clotting of blood?
- A. sodium
- B. magnesium
- C. calcium
- D. potassium
Correct answer: C
Rationale: Calcium plays an essential role in the clotting of blood by being involved in several steps of the coagulation process. It is necessary for the conversion of prothrombin to thrombin, which is a crucial step in forming blood clots. Sodium, magnesium, and potassium do not directly participate in the clotting cascade and are not associated with the coagulation process. Therefore, the correct answer is calcium.
4. Which of the following hormones is secreted by the posterior pituitary gland?
- A. Growth hormone
- B. Luteinizing hormone
- C. Adrenocorticotropic hormone
- D. Antidiuretic hormone
Correct answer: D
Rationale: The correct answer is D: Antidiuretic hormone. Antidiuretic hormone (ADH), also known as vasopressin, is produced by the hypothalamus and stored in the posterior pituitary gland. It plays a key role in regulating the body's water balance by controlling the amount of water reabsorbed by the kidneys. Choices A, B, and C are incorrect because Growth hormone is produced by the anterior pituitary gland, Luteinizing hormone is produced by the anterior pituitary gland, and Adrenocorticotropic hormone is produced by the anterior pituitary gland.
5. Which of the following describes the event of ovulation?
- A. The fallopian tube moves the ovum to the uterus.
- B. The oocyte undergoes its first meiotic division.
- C. The Graafian follicle releases an ovum.
- D. The corpus luteum produces progesterone.
Correct answer: C
Rationale: Ovulation is the release of a mature egg (ovum) from the Graafian follicle in the ovary. This process is essential for fertilization. Choice A is incorrect because the fallopian tube does not move the ovum to the uterus; rather, it provides a pathway for the egg to travel from the ovary to the uterus. Choice B is incorrect as the oocyte undergoes its first meiotic division after ovulation. Choice D is incorrect because the corpus luteum forms after ovulation and is responsible for producing progesterone.
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