Page 421 - Atlas of Histology with Functional Correlations

Circulatory System

CARDIOVASCULAR SYSTEM

Consists of heart, major arteries, arterioles, capillaries, venules, and veins
Two major circuits are systemic circulation and pulmonary circulation
Systemic circulation takes blood to all systems and back to the heart

Pulmonary circulation takes blood to the lungs for gaseous exchange and
back to the heart

TYPES OF ARTERIES

Elastic Arteries

Are the largest vessels and include aorta, pulmonary trunk, and their major
branches
Wall primarily composed of elastic connective tissue mixed with smooth
muscle fibers

Exhibit resilience and flexibility; walls greatly expand during systole (heart
contraction)
During diastole (heart relaxation), walls recoil and force blood forward

Muscular Arteries, Arterioles, and Capillaries

Most numerous vessels with their walls lined with smooth muscle fibers
Control of blood flow through vasoconstriction or vasodilation of lumina
Smooth muscles in arterial walls controlled by axons from the ANS

Arterioles are the small blood vessels with one to five layers of smooth
muscle
Terminal arterioles deliver blood to the smallest blood vessels, the capillaries
Capillaries are the sites of metabolic exchanges between blood and tissues

Capillaries connect arterioles with venules

420