ATI RN
ATI Anatomy and Physiology
1. Peripheral vasodilation results in heat loss through which of the following processes?
- A. conduction
- B. convection
- C. radiation
- D. evaporation
Correct answer: C
Rationale: Peripheral vasodilation is the widening of blood vessels near the surface of the skin, allowing more blood to flow near the skin's surface. This process enhances heat loss primarily through radiation. Radiation is the transfer of heat energy in the form of electromagnetic waves. Conduction involves direct contact between objects, convection involves the transfer of heat through fluid or gas, and evaporation involves the phase change of a liquid to a gas, which cools the surface.
2. Which of the following cardiac valves prevents blood from returning to the left ventricle of the heart?
- A. pulmonic
- B. mitral
- C. tricuspid
- D. aortic
Correct answer: D
Rationale: The correct answer is the aortic valve. The aortic valve is located between the left ventricle and the aorta, preventing the backflow of blood into the left ventricle once it has been pumped out during systole. Choice A, pulmonic, is incorrect as it is associated with the right side of the heart. Choice B, mitral, is incorrect as it is the valve between the left atrium and ventricle. Choice C, tricuspid, is incorrect as it is located between the right atrium and ventricle.
3. 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.
4. Calcium concentration in the blood is controlled by which of the following glands?
- A. Hypothalamus gland
- B. Thyroid gland
- C. Pituitary gland
- D. Parathyroid glands
Correct answer: D
Rationale: The correct answer is Parathyroid glands. The parathyroid glands are responsible for regulating calcium levels in the blood by secreting parathyroid hormone (PTH). PTH helps increase calcium levels in the blood when they are too low. The other glands listed, such as the Hypothalamus, Thyroid, and Pituitary glands, do not directly control calcium concentration in the blood.
5. 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.
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