The Body’s Transport System

Cardiovascular system Heart Blood Vessels – Arteries – Veins – Capillaries Blood

Cardiovascular System The overall function of the circulatory system is to transport materials throughout the body toward and away from particular target organs and tissues. Carries need materials to cells and removes waste from cells.

How the heart works Keeps blood moving through the blood vessels. Large organ composed of Cardiac muscle Two phases 1.The heart muscle relaxes and fills with blood. 2.The heart then contracts and pumps blood forward.

The heart At REST, the heart pumps about 5 QUARTS of blood a minute. During EXTREME EXERTION (exercise) it can pump 40 quarts a minute. Average resting heart beat beats per min beats per min

The heart

Heart Structure Four chambers – Two upper (Atrium) Right Atrium Left Atrium – Two lower (Ventricles) Right Ventricle Left Ventricle -Valves separate Chambers and keep Blood from flowing Backwards.

Key terms Pacemaker Atrium Valve ventricle

Two Loops Pattern of blood flow. In the 1 st loop, blood travels From the heart to the lungs And then back to the heart. -In the 2 nd loop, blood is Pumped from the heart Throughout the body and then Returns again to the heart.

Arteries -Carries blood away from the heart. – Large – Thick-walled, Muscular – Elastic – Oxygenated blood Exception Pulmonary Artery – Carried under great pressure – Steady pulsating Arterioles: smaller vessels, enter tissue

Arteries

Capillaries – Smallest vessel – Microscopic – Walls one cell thick – Nutrients and gases diffuse here

Veins – Carry blood to the heart. – Carries blood that contains waste and CO 2 Exception pulmonary vein – Blood not under much pressure – Valves to prevent much gravity pull

Blood Pressure The force that blood pushes against the walls of blood vessels.