2.2 THE CIRCULATORY SYSTEM

Circulatory System Functions: -transports gases between the lungs and the cells -delivers nutrients to all cells in the body and removes waste products

Anatomy of the Heart Superior Inferior

The Pump - The Heart -drives the circulatory system. -pumps blood to the cells and back to the heart.

The Blood Vessels of the Circulatory system -The main vessels: arteries and veins -The vessels closest to the cells are tiny, and are called capillaries.

Blood Vessels: Arteries Arteries -are thick-walled, -elastic -carry oxygen-rich blood away from the heart to all body cells -When the heart squeezes, a high pressure environment is created in the vessels and pushes blood through them Atherosclerosis -Narrowing and hardening of the arteries due to build up of plaque (cholesterol) -Causes high blood pressure -stroke or heart attack can result if arteries become completely blocked

Blood Vessels: Veins Veins -are thin-walled -inelastic -valves keep blood from flowing backward as it is carried toward the heart -when the heart squeezes, the valves open and close when the heart relaxes

Blood Vessels: Capillaries Capillaries -the smallest vessels in the body -site of oxygen and carbon dioxide exchange between the blood and cells -they connect arteries and veins

Blood flow through the Heart 1.The superior and inferior Vena Cava fills the Right Atrium with Carbon Dioxide rich blood 2.The AV valve opens 3. Right Ventricle fills with the Carbon dioxide rich blood The carbon dioxide rich blood gets pushed through the pulmonary arteries back to the lungs for gas exchange 1.The pulmonary vein delivers oxygen rich blood to the left atrium 2.The AV valve opens 3.Left ventricle fills with Oxygen rich blood that gets pushed through the aorta to all parts of the body 4.Exchange of gases/nutrients/ waste occurs at the capillaries

Heart Sounds “LUB DUB” LUB is the closing of the AV valves DUB is the closing of the Semi Lunar Valves LISTEN to your heart:

Blood Components An adult body holds approximately 5 L of blood, 3L is plasma, the remaining 2L is made up of hematocrit (RBC, WBC, Platlets) Components: 1.Red Blood Cells (RBC) – carry oxygen/carbon dioxide around the body 2.White Blood Cells (WBC) – needed for immune defence 3.Platlets – needed for repair 4.Plasma – fluid portion of the blood

Homework 1.What causes your heart sounds? 2.A murmur is a conditions in which your heart valves do not close properly. How would this affect your heart sounds? 3.What is the difference between an artery and a vein? 4.A) what is the name of the major artery in the body? 5.B) what is the name of the major vein in the body? 6.What is the role of capillaries? 7.What allows red blood cells to carry oxygen? 8.Using the diagram provided on a handout, begin with blood entering the heart at the pulmonary vein and create a flowchart that shows the pathway blood takes through the heart.