A 34-year-old man presents with a 5-day history of a painful sore on his hand. Physical examination reveals a 0.5-cm abscess on the extensor surface of the left hand that drains a thick, purulent material. Diapedesis of leukocytes into and around this patient's infected wound occurs primarily at which of the following anatomic locations?: (A) Lymphatic capillaries, (B) Postcapillary venules, (C) Precapillary aerioles, (D) Small dermal aeries
Answer is B. One of the earliest responses following tissue injury occurs within the microvasculature at the level of the capillary and postcapillary venule.