Chapter 9 section 2

Circulatory System

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CirculationYour body

resembles a large roadmap, There are routes or “arteries” that take you downtown to the “heart” of the city.

The Body’s Delivery System

• Your cardiovascular system includes the blood, heart, and blood vessels.

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• Your heart controls blood flow through all parts of the body

• 4 chambers ( or compartments )• Left & Right Atrium — upper two chambers• Left & Right Ventricle — lower two chambers

• Blood flows only from an atrium to a ventricle.

• A wall between the two atriums or the two ventricles separates oxygen-rich from oxygen-poor blood.

The Heart

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Types of Circulation

• Circulatory system is divided into three sections

• Coronary• Pulmonary• systemic

Coronary Circulation

• Coronary circulation is the flow of blood to and from the tissues of the heart.

• When blocked, oxygen and nutrients cannot reach the cells of the heart which can cause a heart attack.

Pulmonary Circulation

• In Pulmonary circulation, blood flows through the heart to the lungs, where carbon dioxide and other waste materials diffuse out, oxygen diffuses in, and the blood goes back to the heart.

• The oxygen-rich blood is pumped into the aorta, the largest artery in your body.

Systemic Circulation

• Systemic circulation moves oxygen-rich blood to all the organs and body tissues, except the heart and lungs, and returns oxygen-poor blood to the heart.

• It is the largest of the three sections of your circulatory system.

Blood Vessels

• Blood Vessels carry blood to every part of your body. They resemble very long and skinny tunnels that are all through your body.

3 Types of Blood Vessels

Arteries Capillaries Veins

Arteries

• Arteries are blood vessels that move blood away from the heart.

• They have thick, elastic walls made of connective tissue and smooth muscle tissue

Veins

• Veins carry blood back to the heart.

• They have one-way valves that keep blood moving toward the heart.

• If blood flows backwrad, the pressure of the blood against the valves causes them to close.

Capillaries

• Capillaries are microscopic blood vessels that connect arteries to veins.

• The walls of capillaries are only one cell thick.

Blood Pressure

• Blood pressure is the force of the blood on the walls of the blood vessels.– Blood pressure is highest in arteries and

lowest in veins. A rise and fall of pressure occurs with each heartbeat.

– Your brain tries to keep your blood pressure normal. Your brain sends messages to your heart to raise or lower your blood pressure by speeding up or slowing down your heart rate.

If you listen to your heartbeat, it makes a lub dub

sound.

The lub is when blood is pushed out of the

heart into the body and the dub is the reloading of the heart with more blood ready to push it

out to the body

Cardiovascular Disease

• Any disease that affects the cardiovascular system can seriously affect the health of your entire body.

• The heart, blood vessels, and blood

• Heart disease is the leading cause of death in humans in the United States.

Cardiovascular Diseases

1. Atherosclerosis — fatty deposits build up on arterial walls and clog arteries

• If a coronary artery is blocked then a heart attack can occur

• Open-heart surgery then may be needed to correct the problem

2. Hypertension — high blood pressure• The artery walls no longer contract and dilate easily because

they have lost their elasticity

Prevention:• Follow a healthful diet, exercise, and have regular checkups.• Avoid smoking; it increases carbon monoxide in the blood

making the heart beat faster and harder.

Functions of the Lymphatic System

• The lymphatic system collects tissue fluid and returns it to the blood.1. Lymph–tissue fluid that contains water and

dissolved substances• contains lymphhocytes—type of white blood cell

that helps the body defend itself against disease causing organisms

2. Lymph nodes—bean-shaped organs of varying size found throughout the body; filter out microorganisms and foreign materials from lymphocytes

• Heart Rate can be determined using a Stethoscope

Average Heart Rate of some Mammals

28

200

50 30 970 40

376

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Heart Facts• Hold out your hand and make a fist. If you're a kid, your

heart is about the same size as your fist, and if you're an adult, it's about the same size as two fists.

• Your heart beats about 100,000 times in one day and about 35 million times in a year. During an average lifetime, the human heart will beat more than 2.5 billion times.

• Give a tennis ball a good, hard squeeze. You're using about the same amount of force your heart uses to pump blood out to the body. Even at rest, the muscles of the heart work hard--twice as hard as the leg muscles of a person sprinting.