Physiology 1020 Lecture 9: Physiology Lecture 9 Circulatory System 2
29 Sep 2017
School
Department
Course
Professor
Document Summary
The total blood volume of an average human being is roughly 5 liters. The largest portion (70%) is contained in the veins. Since they contain the most capacity, the veins are often referred to as the capacitance vessels or blood. Combined, the arteries contain 10% of the tbv, while the heart and lungs contain about 15%. The capillaries, which are the gas exchange vessels, contain the last 5% of the. The arteries have the highest blood pressure and velocity, yet have a very low cross-sectional area. As a consequence, these vessels rapidly distribute the blood throughout the body. The arterioles have a lower blood pressure and velocity, yet the cross-sectional area is higher. These vessels are the site of highest resistance in the circulation and help regulate blood flow to an organ. The blood velocity is lowest in the capillaries while their total cross-sectional area is the highest in the circulation.
