Circulatory System

Circulatory System 1. The circulatory system is composed of a group of organs which transport food and oxygen to and remove waste from every cell in the body. An adult human contains about ten pints of blood.

The Heart 2. The heart acts as the pump of the circulatory system. 3. It keeps the blood moving endlessly through the body. There are four main parts of the heart which are divided into two distinct halves-right and left.

Atria 4. Inside each half are two chambers. The top one is the atrium which receives the blood and acts as a tiny reservoir.

Ventricles 5. When the heart relaxes, the blood is pulled into the lower chamber called the ventricle. 6. A one way valve, like a one-way door, keeps the blood from backing up into the atrium.

Ventricles When the heart contracts, the blood is pushed out of the heart. Another valve keeps the blood from running back into the ventricle.

Heartbeat 7.The "heartbeat" that is heard through a stethoscope is the opening and closing of these valves.

Blood through the heart

Arteries & Veins 7.The veins carry blood to the heart and appear to be a darker color because of the lack of oxygen. 8.The arteries carry blood away from the heart and are rich in oxygen from the lungs. Arteries are bright red in color.

Circulatory System 10. After blood completes Its journey through the heart, it is in the left ventricle. 11. From there, it is ready to flow into the aorta for its trip around the body.

Circulatory System 12.Since this trip is so much longer than the round trip to the lungs, the left ventricle must pump much more powerfully than the right. 13. This is why the heartbeat is felt on the left side of the body even though the heart is in the center of the body. 14. The muscles are also much thicker on the left side.

Circulatory System After oxygenated blood reaches the aorta, it flows into branch arteries leading to the head, arms, stomach, intestines, liver, kidneys and all inside organs. Other branches carry blood into the legs and feet.

Capillaries 15. It travels first in large arteries, then smaller ones, and finally into the tiniest blood vessels of all-the capillaries. 16. Here it drops its food and oxygen and picks up waste products from the body cells.

The CAPILLARY Capillaries link Arteries with Veins they exchange materials between the blood and other body cells. the wall of a capillary is only one cell thick The exchange of materials between the blood and the body can only occur through capillaries.

The CAPILLARY A collection of capillaries is known as a capillary bed. artery vein capillaries body cell

Circulatory System It is now deoxygenated blood and is dark red or bluish In color. It passes into tiny veins that lead to larger veins and finally back into the right atrium. This complete trip takes less than a minute to complete.

SUMMARY copy and complete the following; Arteries take blood ______ from the heart. The walls of an artery are made up of thick _________ walls and elastic fibres. Veins carry blood ________ the heart and also have valves. The _________ link arteries and veins, and have a one cell thick wall. away muscular towards capillaries

Map of the Heart Activity

Pulmonary Artery : Artery to Lungs The Heart Pulmonary Artery : Artery to Lungs Artery to Head and Body: Aorta Superior Vena Cava: Vein from Head and Body Pulmonary Vein: Vein from Lungs Right Atrium Left Atrium Mitral valve: Also known as the biscupid valve Tricuspid valve Left Ventricle Right Ventricle Inferior Vena Cava

How the blood flows through the body. STEP ONE blood from the body blood from the lungs 1. The heart beat begins when the heart muscles relax and oxygen-poor blood flows from the body into the atria.

How the blood flows through the body. STEP TWO 2. The atria then contract and the tricuspid valves open to allows the blood to flow into the right ventricle.

3. The tricuspid valves close to stop blood from flowing backwards. How does the Heart work? STEP THREE 3. The tricuspid valves close to stop blood from flowing backwards. The right ventricles contracts forcing the blood to the lungs, where the blood releases waste gases (CO2) and picks up oxygen.

How the blood flows through the body Step 4 4. The newly oxygen- rich blood returns to the heart and enter the left atrium Step 5 5.Blood flows through the left atrium , through the bicupid valve, into the left ventricle. Step 6 6. The left ventricle pumps the oxygen- rich blood to all parts of the body through the aorta.