Flow of Blood Through Blood Vessels

Blood Vessels

Flow of Blood Through Blood Vessels Figure 19.1a Arteries Arterioles Capillaries Venules Veins

Blood Flow

Arteries Function: Carry blood away from the heart Figure 19.2b

Arterioles Function: Deliver blood to capillaries

Capillaries Function: In the lungs – oxygen enters blood, carbon dioxide leaves In the small intestines – receive digested nutrients In endocrine glands – pick up hormones In the kidneys – removal of nitrogenous wastes

Capillaries: Function

Capillaries & Venules Function of Venules: Collect and drain blood into veins A= arteriole B= vein C = nerve

Veins Function: Return blood from capillaries toward the heart

Structure of Blood Vessels 3 layers (tunics) Tunica intima – single layer of epithelial cells Tunica media – sheets of smooth muscle Tunica externa –connective tissue Lumen – central blood-filled space of a vessel

Differences in Structure Between Arteries and Veins Artery walls are thicker Veins have valves Arteries and arterioles are elastic Veins have larger lumens

Differences in Structure Between Arteries and Veins

Structure of Capillaries Have a thin tunica intima (one layer of simple squamous epithelium. No tunica media or externa

Pulmonary Circulation Pulmonary trunk leaves the right ventricle and divides into right and left pulmonary arteries Superior and inferior pulmonary veins carry oxygenated blood into the left atrium

Systemic Circulation

The Aorta

Vena Cavas Superior vena cava returns blood from body regions superior to the diaphragm Inferior vena cava r eturns blood from body regions inferior to the diaphragm

Hepatic Portal System

Cerebral Arterial Circle (Circle of Willis)

Blood Pressure

Sphygmomano- meter Stethoscope

Blood Pressure

Pulse