A patient comes to the emergency department (ED) and reports a swollen and painful leg but denies sustaining any injury. The physical examination reveals a tense calf muscle, decreased sensation to the foot and leg, and absent pedal pulses. The cardiac-vascular nurse asks the patient when the symptoms began because:

Correct Answer: C

Rationale: Acute limb ischemia (e.g., from thrombosis or embolism) can cause irreversible muscle/nerve damage within 4-6 hours due to anoxia, making symptom onset timing critical for intervention. A is incorrect (both are sudden), B is delayed, and D is unrelated.

Correct Answer: A

Rationale: Arteries (Choice A) are the blood vessels that carry blood away from the heart, delivering oxygenated blood to the body (via systemic arteries) or deoxygenated blood to the lungs (via pulmonary arteries). Veins (Choice B) carry blood toward the heart, capillaries (Choice C) facilitate exchange between blood and tissues, and venules (Choice D) are small veins that collect blood from capillaries. Only arteries match the description, making Choice A correct.

Correct Answer: C

Rationale: Blood enters via the venae cavae into the right atrium, flows to the right ventricle, is pumped to the lungs, returns to the left atrium via pulmonary veins, then enters the left ventricle, and exits through the aorta. This reflects normal adult circulation.

Correct Answer: D

Rationale: Fenestrated capillaries, with pores in their endothelial walls, are found in the intestines, kidneys, and endocrine glands to facilitate rapid exchange (e.g., nutrient absorption). Muscles and adipose tissue have continuous capillaries, and the CNS has tight junctions (blood-brain barrier).

Correct Answer: A

Rationale: Diffusion is the primary mechanism for exchange in capillaries, driven by concentration gradients (e.g., oxygen, CO2). Filtration and osmosis contribute to fluid movement, but diffusion dominates for most substances.