ATI RN
ATI Anatomy and Physiology
1. 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.
2. 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.
3. What effect does aldosterone secretion have on electrolyte levels?
- A. Calcium levels are decreased
- B. Sodium levels are increased
- C. Potassium levels are increased
- D. Magnesium levels are decreased
Correct answer: B
Rationale: Aldosterone is a hormone that primarily acts on the kidneys to increase the reabsorption of sodium and water into the bloodstream. As a result, sodium levels are increased. Choices A, C, and D are incorrect. Aldosterone does not significantly affect calcium, potassium, or magnesium levels.
4. 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.
5. Which of the following types of cells is primarily responsible for the destruction of old cells and invasive micro-organisms?
- A. Basophils
- B. Eosinophils
- C. B-cells
- D. Macrophages
Correct answer: D
Rationale: Macrophages are a type of white blood cell that plays a crucial role in the immune system by engulfing and digesting cellular debris, foreign substances, microbes, cancer cells, and old or damaged cells. Basophils are primarily involved in allergic reactions and parasitic infections, eosinophils combat multicellular parasites and have a role in allergic reactions, and B-cells are responsible for producing antibodies. Therefore, the correct answer is macrophages as they are specialized in phagocytosis and removal of unwanted cells and microorganisms.
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