Cardiovascular physiology: Blood vessels

The vascular system is composed of arteries, arterioles, capillaries, venules and veins.

Arteries and arterioles transport blood from the heart to the tissues. Capillaries are the main site of exchange of gases and metabolites across their thin walls. Venules and veins return blood to the right side of the heart.

Arteries and arterioles

Large arteries act as elastic pulsation-dampening distribution vessels that dampen out oscillations pressure between systole and diastole.

Small arteries and arterioles contain relatively more smooth muscle are the primary controllers of blood flow through to the tissues via vasoconstriction and vasodilation.

Veins

Veins may be considered thin-walled capacitance and return vessels. They have larger diameter lumens than equivalent arteries and provide less resistance. They have thin distensible vessels and contain approximately 70% of total blood volume.

Capillaries and venules

Capillaries are the interface between the arterial and venous systems. They (along with venules) are the sites of exchange and return in the microcirculation