1. Circulatory System

2. Introduction Imagine turning on a faucet. What happens? Imagine turning on a faucet. What happens? Just as you expect water to flow when you turn on the faucet, your body needs a continuous supply of oxygen and nutrients and a way to remove wastes. Just as you expect water to flow when you turn on the faucet, your body needs a continuous supply of oxygen and nutrients and a way to remove wastes. Materials are moved throughout your body by your cardiovascular system in a similar way. Materials are moved throughout your body by your cardiovascular system in a similar way.

3. Blood vessels carry the blood to every part of your body. Blood vessels carry the blood to every part of your body. Blood moves oxygen and nutrients to cells and carries carbon dioxide and other wastes away from the cells. Blood moves oxygen and nutrients to cells and carries carbon dioxide and other wastes away from the cells. Movement of materials into and out of the cells occurs by diffusion and active transport. Movement of materials into and out of the cells occurs by diffusion and active transport. Diffusion occurs when a material moves from an area where there is more of it to an area where there is less of it. Diffusion occurs when a material moves from an area where there is more of it to an area where there is less of it. Active transport is the opposite of diffusion and requires energy and diffusion does not. Active transport is the opposite of diffusion and requires energy and diffusion does not.

4. The Heart Your heart is an organ made of cardiac muscular tissue. Your heart is an organ made of cardiac muscular tissue. Your heart has 4 chambers: 2 upper chambers are called right and left atriums and the 2 lower chambers are called right and left ventricles. Your heart has 4 chambers: 2 upper chambers are called right and left atriums and the 2 lower chambers are called right and left ventricles.

5. Atria & Ventricles During one heartbeat, both atriums contract at the same time. During one heartbeat, both atriums contract at the same time. Then both ventricles contract at the same time. Then both ventricles contract at the same time. A one way valve separates each atrium from the ventricle below it. A one way valve separates each atrium from the ventricle below it. The blood flows in only one direction from an atrium to a ventricle, then from a ventricle into a blood vessel. The blood flows in only one direction from an atrium to a ventricle, then from a ventricle into a blood vessel. A wall prevents blood from flowing between the two atriums or the two ventricles. This wall keeps blood rich in oxygen separate from blood low in oxygen. If the oxygen-rich blood and oxygen-poor blood were to mix, your body’s cells would not get all the oxygen they need. A wall prevents blood from flowing between the two atriums or the two ventricles. This wall keeps blood rich in oxygen separate from blood low in oxygen. If the oxygen-rich blood and oxygen-poor blood were to mix, your body’s cells would not get all the oxygen they need.

6. 3 Types of Circulation Scientists have divided the circulatory system into 3 sections-coronary, pulmonary, and systemic circulation. Scientists have divided the circulatory system into 3 sections-coronary, pulmonary, and systemic circulation.

7. Coronary Circulation Is the flow of blood to and from the tissues of the heart. Is the flow of blood to and from the tissues of the heart. When the coronary circulation is blocked, oxygen and nutrients cannot reach all the cells of the heart. This can result in a heart attack. When the coronary circulation is blocked, oxygen and nutrients cannot reach all the cells of the heart. This can result in a heart attack.

8. Pulmonary Circulation The flow of blood through the heart to the lungs and back to the heart. The flow of blood through the heart to the lungs and back to the heart. The blood returning from the body through the right side of the heart and to the lungs contains cellular wastes. The blood returning from the body through the right side of the heart and to the lungs contains cellular wastes. In the lungs, these wastes diffuse out of the blood, and oxygen diffuses into the blood. Then the blood returns to the left side of the heart. In the lungs, these wastes diffuse out of the blood, and oxygen diffuses into the blood. Then the blood returns to the left side of the heart. The oxygen-rich blood is pumped from the left ventricle into the aorta, the largest artery in your body. The oxygen-rich blood is pumped from the left ventricle into the aorta, the largest artery in your body. The oxygen-rich blood flows to all parts of your body. The oxygen-rich blood flows to all parts of your body.

9. Systemic Circulation Oxygen-rich blood moves to all of your organs and body tissues, except the heart and lungs, by systemic circulation. Oxygen-rich blood moves to all of your organs and body tissues, except the heart and lungs, by systemic circulation. This is the largest of the 3 sections of your circulatory system. This is the largest of the 3 sections of your circulatory system. Oxygen-rich blood flows from your heart in the arteries of this system. Nutrients and oxygen are then delivered by the blood to your body cells and exchanged for carbon dioxide and wastes. The blood then returns to your heart in the veins of the systemic circulation system. Oxygen-rich blood flows from your heart in the arteries of this system. Nutrients and oxygen are then delivered by the blood to your body cells and exchanged for carbon dioxide and wastes. The blood then returns to your heart in the veins of the systemic circulation system.

10. Blood Vessels Blood moves by the pumping of the heart and flows from arteries to veins. Blood moves by the pumping of the heart and flows from arteries to veins. Capillaries are the connections between arteries and veins. Capillaries are the connections between arteries and veins. All are considered to be blood vessels. All are considered to be blood vessels.

11. Arteries As blood is pumped out of the heart, it travels through arteries, capillaries, then veins. As blood is pumped out of the heart, it travels through arteries, capillaries, then veins. Arteries are blood vessels that carry blood away from the heart. They have thick, elastic walls made of connective tissue and smooth muscle tissue. Arteries are blood vessels that carry blood away from the heart. They have thick, elastic walls made of connective tissue and smooth muscle tissue. Each ventricle of the heart is connected to an artery. Each ventricle of the heart is connected to an artery. The right ventricle is connected to the pulmonary artery. The right ventricle is connected to the pulmonary artery. The left ventricle is connected to the aorta. The left ventricle is connected to the aorta. Every time your heart contracts, blood is moved from your heart into arteries. Every time your heart contracts, blood is moved from your heart into arteries.

12. Veins The blood vessels that carry blood back to the heart are called veins. The blood vessels that carry blood back to the heart are called veins. Veins have one-way valves that keep blood moving toward the heart. If the blood flows backward, the pressure of the blood against the valves cause them to close. Veins have one-way valves that keep blood moving toward the heart. If the blood flows backward, the pressure of the blood against the valves cause them to close. The flow of blood through the veins is also helped by your skeletal muscles. When skeletal muscles contract, the veins in these muscles are squeezed and help blood move toward the heart. The flow of blood through the veins is also helped by your skeletal muscles. When skeletal muscles contract, the veins in these muscles are squeezed and help blood move toward the heart. Two major veins return blood from your body to your heart- superior vena cava returns blood from your head and neck, inferior vena cava returns blood from your abdomen and lower body. Two major veins return blood from your body to your heart- superior vena cava returns blood from your head and neck, inferior vena cava returns blood from your abdomen and lower body.

13. Capillaries Arteries and veins are connected by microscopic blood vessels called capillaries. Arteries and veins are connected by microscopic blood vessels called capillaries. The walls of capillaries are only one cell thick making it easy for nutrients and oxygen to diffuse into body cells and cellular waste to diffuse into capillaries from body cells. The walls of capillaries are only one cell thick making it easy for nutrients and oxygen to diffuse into body cells and cellular waste to diffuse into capillaries from body cells. You can see capillaries when you have a bloodshot eye. They are the tiny red lines you see in the white area of your eye. You can see capillaries when you have a bloodshot eye. They are the tiny red lines you see in the white area of your eye.

14. Blood Pressure Is the force of blood on the walls of the blood vessels. Is the force of blood on the walls of the blood vessels. This pressure is highest in arteries and lowest in veins. This pressure is highest in arteries and lowest in veins. Normal resting pulse rates are 60 to 100 heartbeats per minute for adults and 80 to 100 beats per minute for children. Normal resting pulse rates are 60 to 100 heartbeats per minute for adults and 80 to 100 beats per minute for children. Blood pressure is measured in large arteries and is expressed in two numbers. (120 over 80) Blood pressure is measured in large arteries and is expressed in two numbers. (120 over 80) Systolic pressure is the first number and it is a measure of pressure caused when the ventricles contract and blood is pushed out of the heart. Systolic pressure is the first number and it is a measure of pressure caused when the ventricles contract and blood is pushed out of the heart. The second number is diastolic pressure and it occurs as the ventricles fill with blood just before they contract again. The second number is diastolic pressure and it occurs as the ventricles fill with blood just before they contract again. Your body tries to keep blood pressure normal. Your body tries to keep blood pressure normal.

15. Cardiovascular Disease Atherosclerosis is caused by fatty deposits that build up on arterial walls. Eating foods high in cholesterol and saturated fats can cause these deposits to form. This can occur in any artery of the body, but is especially serious in coronary arteries. Atherosclerosis is caused by fatty deposits that build up on arterial walls. Eating foods high in cholesterol and saturated fats can cause these deposits to form. This can occur in any artery of the body, but is especially serious in coronary arteries. Hypertension or high blood pressure is caused when blood pressure is higher than normal. Most of the time, extra strain is put on the heart and it must work harder to keep blood flowing. Atherosclerosis is one cause of this. Hypertension or high blood pressure is caused when blood pressure is higher than normal. Most of the time, extra strain is put on the heart and it must work harder to keep blood flowing. Atherosclerosis is one cause of this. Heart Failure results when the heart cannot pump blood efficiently. It can be caused when heart tissue is weakened by disease or when heart valves do not work properly. People with heart failure usually are short of breath and tired. They also experience fluid build up in the arms, legs, and lungs. Heart Failure results when the heart cannot pump blood efficiently. It can be caused when heart tissue is weakened by disease or when heart valves do not work properly. People with heart failure usually are short of breath and tired. They also experience fluid build up in the arms, legs, and lungs. Smoking causes blood vessels to contract and makes the heart beat faster and harder. It also increases carbon monoxide levels in the blood. Smoking causes blood vessels to contract and makes the heart beat faster and harder. It also increases carbon monoxide levels in the blood.