Getting to the Heart of the

Matter…

The Circulatory

System

The Circulatory System

•Components:– Heart – cardiac muscle, involuntary– blood vessels – lined w/smooth

muscles– Blood – is a tissue

•AKA (also known as) - Cardiovascular System – Cardio – means heart– Vascular – means blood vessels

•The blood vessels of the circulatory system reach throughout the entire body

•Blood flows through these vessels to every organ in the body

•Capillaries reach every cell of the body

Functions of the Circulatory System

• Carries needed materials to the cells– Oxygen from the lungs – Glucose for energy

• Carries waste products away from the cells– Carbon dioxide (CO2)– Other wastes

• Carries cells that fight disease throughout the body (white blood cells)

The Heart• The heart is made up

of four chambers (sections)

• Split into left and right side by a muscular wall (septum)

• The heart works with the lungs to provide oxygen to the body

The Parts of the Heart

• Atrium – the two upper chambers of the heart– Receive blood coming into the heart

• Ventricles – the two lower chambers of the heart– Pump blood out of the heart

• Valve – a flap of tissue that prevents blood from flowing backward– Located between each chamber and in

the veins

Label the heart on your notes

How the Heart Works

• The heart muscle relaxes and the atrium fill with blood

• The atrium contract, pushing blood into the ventricles

• The ventricles contract to pump the blood out of the heart and into the arteries

The Heart Beat

•The sound that your heart makes is the valves between the chambers opening and closing

•lub-dub, lub-dub

Your heart does not work alone

•Your brain tracks the conditions around you—climate, stress, and your level of physical activity—and adjusts your cardiovascular system to meet those needs

Regulation of Heartbeat

• The pacemaker regulates the heart beat.–A group of cells located in the right atrium

–Sends signals that make the heart contract

–Constantly receives internal stimuli about the body’s oxygen needs

Two Loops

• In one loop– blood travels

from the heart to the lungs and back to the heart.

• In the second loop– blood travels

from the heart to the body and back to the heart.

http://www.mikecurtis.org.uk/heart.htm

First Loop – to the lungs and

back

• Blood from the body enters the right atrium

• Through a valve to the right ventricle

• Out of the right ventricle into the pulmonary artery to the lungs where the blood releases waste gases and picks up oxygen

• L & R atria pump together

Do right and left seem backward?

• That's because you're looking at an illustration of somebody else's heart

• To think about how your own heart works, imagine wearing the picture on your chest

Second Loop-to the body and

back

• The newly oxygen-rich blood (shown in red) returns to the heart and enters the left atrium

• Through a valve into the left ventricle

• The left ventricle contracts, pushing the blood into the aorta eventually to all parts of the body

• L &R ventricles pump together

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Three kinds of Blood Vessels

•Arteries – blood vessels that carry blood away from the heart

•Veins – blood vessels that carry blood back to the heart

•Capillaries – tiny blood vessels capable of exchanging substances between the blood and body cells

Three kinds of Blood Vessels

Study Your Notes!!

• You will take a quiz over these notes tomorrow