Lymph capillary Capillary bed Tissue cells Venule Lymph duct Arteriole
6. Capacitance Vessel -Systeru veins )Have a large diameter but a thin wall which includes a thin muscle coat >The number is about twice as much as the number of arteries >have an enormous capacity to hold blood
6. Capacitance Vessel – Systemic veins ➢Have a large diameter but a thin wall, which includes a thin muscle coat. ➢The number is about twice as much as the number of arteries, ➢have an enormous capacity to hold blood
Artery Vein Tunica intima (endothelial cells Valve elastin Tunica media (smooth muscle Tr Tunica externa (loose fibrous connective tissue) Serosa (epithelial cells)
Capacitance Vessel-. veins Most of the time veins hold more than half the blood volume the great distensibility of veins makes their capacity adjustable In times of need a considerable amount of blood can be squeezed from the veins to areas where it may be needed
Capacitance Vessel – Systemic veins ➢ Most of the time, veins hold more than half the blood volume . ➢ the great distensibility of veins makes their capacity adjustable. ➢ In times of need, a considerable amount of blood can be squeezed from the veins to areas where it may be needed
Figure 14.4. The distribution of blood within the circulatory system at rest. From Circulation by Bjorn Folkow and Eric Neil. Copyright 1971 by Oxford University Press, Inc. Reprinted by permission Heart 15 8-11% 10 Syst arteries 10-12% Cap 4-5% Systemic veins 60-70% venule les