Chapter 20.1, Problem 12AYLO

Summary Introduction

To discuss:

The structural differences between muscular venules, medium veins, and large veins.

Introduction:

Veins carry de-oxygenated blood from the organs to the heart. They are also called as capacitance vessels, as they have flaccid and thin walls. When compared to arteries, they accommodate 64% more volume of blood, with only 13% of the blood. The veins have lower blood pressure than arteries and have a steady blood flow. The average blood pressure seen in the arteries is 90 to 100 mm Hg and rises up to 100 mm Hg during systole; in the veins, it is only 10 mm Hg. Unlike arteries, some veins are equipped with valves that ensure a one-way flow of blood. When empty, the veins collapse, get flattened, and form an irregular shape in the histological sections.