The C ardiovascular System

1. The Cardiovascular System

2. Functions • Delivery of needed materials: Blood transports oxygen from your lungs to your other body cells. It also transports the glucose your body cells use to produce energy.

3. Functions • Removing waste products: Blood carries carbon dioxide (a waste product from the break down of glucose) to the lungs so it can be exhaled.

4. Functions • Fighting disease: The cardiovascular system transports cells that attack disease- causing organisms.

5. The cardiovascular system is composed of: • Heart • Arteries • Capillaries • Veins

6. The Heart • The heart is a hollow, muscular organ that pumps blood throughout the body. • The right side of the heart is completely separated from the left side by a wall of tissue called the septum. Each side has two chambers.

7. Each upper chamber is called atrium (plural atria). Blood enters the heat through the atria. • Each lower chamber is called ventricle. Blood leaves the heart through the ventricles. • In the right atrium there is a group of cells called the pacemaker, which sends out signals that make the heart muscle contract.

8. How the heart works • The cardiac muscle relaxes allowing blood to flow into the atria. • Then the atria contract, squeezing blood through the valves and into the ventricles. • Next the ventricles contract, closing the valves between the atria and ventricles and squeezing blood into the large blood vessels.

9. A two loop system • The circulatory system has two loops. • In the first loop, oxygen poor blood travels from the heart to the lungs, then back to the heart as oxygen rich blood. • In the second loop, oxygen rich blood is pumped from the heart throughout the body, then back to the heart as oxygen poor blood.

10. 2. Oxygen poor blood enters the heart through the right atrium • 4. Oxygen rich blood enters the heart through the left atrium • 3. Oxygen poor blood leaves the heart through the right atrium • 1. Oxygen rich blood leaves the heart through the left ventricle

11. Arteries • When blood leaves the heart it travels through arteries. • The walls of the arteries are generally very thick. (3 cell layers: one layer of epithelial cells, one layer of smooth muscle cells and one layer of connective tissue cells) • Arteries regulate blood flow, adjusting the amount of blood sent to different organs

12. Capillaries • Blood flow from small arteries enters the capillaries. • In the capillaries materials are exchanged between the blood and the body’s cells. • Capillary walls are only one cell thick.

13. Veins • After blood moves through the capillaries, it enters larger blood vessels, which carry blood back to the lungs. • The walls of veins are also three cells thick, with muscle in the middle layer. However they are much thinner than arteries.

14. What is blood pressure • Blood pressure is the force blood exerts against the walls of the blood vessel. • Blood pressure is measured using a sphygmomanometer, and is expressed as millimeters of mercury. • The first number is the pressure while the ventricles contract and pump blood into the arteries. • The second number measures blood pressure while the ventricles relax.