AP BIOLOGY

Detailed explanation-1: -Veins are favored over arteries because they have thinner walls, and thus they are easier to pierce. There is also lower blood pressure in veins so that bleeding can be stopped more quickly and easily than with arterial puncture.

Detailed explanation-2: -Relevant Anatomy. The median cubital and cephalic veins are preferred for blood sampling, but other arm and hand veins may be used. The cephalic vein is located on the lateral (radial) side of the arm, and the basilic vein is located on the medial (ulnar) side.

Detailed explanation-3: -The antecubital area of the arm is usually the first choice for routine venipuncture. This area contains the three vessels primarily used by the phlebotomist to obtain venous blood specimens: the median cubital, the cephalic and the basilic veins.

Detailed explanation-4: -In veins blood flows in a relatively low pressure compared to oxygenated blood being pumped through arteries at a higher pressure. So if the artery is punctured with a needle this will lead to a lot of blood loss. So mainly injections are administered through the vein rather than an artery.

Detailed explanation-5: -Thus, drawing blood from veins is preferred compared to arteries. This is because veins run superficially.