ATI RN
ATI Anatomy and Physiology
1. Which of the following is a role of platelets in hemostasis?
- A. formation of plugs
- B. promotion of vasodilation
- C. conversion of prothrombin to thrombin
- D. activation of calcium
Correct answer: A
Rationale: Platelets play a crucial role in hemostasis by forming plugs to stop bleeding. Choice B is incorrect because platelets do not promote vasodilation; instead, they help in vasoconstriction. Choice C is incorrect as the conversion of prothrombin to thrombin is a function of the coagulation cascade involving various clotting factors, not platelets. Choice D is incorrect as platelets do not directly activate calcium; instead, they play a role in the activation of other clotting factors.
2. Which of the following illustrates a positive feedback mechanism?
- A. Maintaining blood pressure
- B. Uterine contractions during childbirth
- C. Body temperature control
- D. Control of blood sugar
Correct answer: B
Rationale: The correct answer is uterine contractions during childbirth. This is an example of a positive feedback mechanism where the initial stimulus (contractions) leads to an increase in intensity and frequency, ultimately resulting in childbirth. In contrast, choices A, C, and D (maintaining blood pressure, body temperature control, and control of blood sugar) are examples of negative feedback mechanisms. These mechanisms work to maintain stability by counteracting any deviations from the set point, rather than amplifying the response like in a positive feedback mechanism.
3. Are the ears lateral to the eyes?
- A. True
- B. False
- C. Not Sure
- D. None of the above
Correct answer: A
Rationale: The correct answer is A: True. Lateral means towards the side or away from the midline. In human anatomy, the ears are located on the sides of the head, which is indeed lateral to the eyes that are positioned more towards the front of the face. Therefore, the statement that the ears are lateral to the eyes is true. Choice B is incorrect because the ears are not positioned closer to the midline than the eyes. Choice C is incorrect as the relationship between the ears and eyes in terms of lateral positioning can be determined anatomically. Choice D is incorrect as there is a clear anatomical relationship between the ears and eyes.
4. Which of the following structures of the gastrointestinal system absorbs iron and bile salts?
- A. Ileum
- B. Jejunum
- C. Colon
- D. Duodenum
Correct answer: A
Rationale: The correct answer is the Ileum. The Ileum is the final section of the small intestine where the absorption of key nutrients such as iron and bile salts occurs. The Jejunum mainly absorbs nutrients like carbohydrates and proteins, while the Duodenum primarily facilitates the absorption of minerals and vitamins. The Colon's main function is to absorb water and electrolytes, not iron and bile salts. Therefore, choices B, C, and D are incorrect.
5. 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.
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