Mammalian Heart

The Heart

• Consists of TWO pumps, which are separated by a muscular wall called the septum.

• Right pump receives deoxygenated blood.– Pumps this blood to the lungs to pick up

oxygen.

• Left pump receives oxygenated blood.– Pumps this blood through the body.

Anatomy of the Heart

Anatomy of the Heart

• The heart is made up of four chambers– Two Atria– Two Ventricles

• Blood enters the heart into the right and left atria– Systemic system enters the right– Pulmonary system enters the left

• Blood leaves the heart through the right and left ventricles.– Ventricles are very muscular because they

need to pump blood through the body.

Anatomy of the Heart

Blood Flow in the Heart

Two Blood Circuits

• The PULMONARY CIRCUIT consists of blood vessels that bring blood to and from the lungs to pick up oxygen and drop off carbon dioxide.

Two Blood Circuits

• The SYSTEMIC CIRCUIT consists of blood vessels that bring oxygenated blood to the body’s cells and deoxygenated blood back to the heart.

One-Way Street

• Blood only moves in ONE direction through the circulatory system.

• This consistent blood flow is maintained with valves found in the heart and veins.

• These valves prevent blood from flowing backwards.

• There are four important valves in the heart.– 2 Atrioventricular (AV) valves – 2 Semilunar valves

Heart Valves

• 2 Atrioventricular Valves– These valves separate the atria from the

ventricles.– The two AV valves are the Tricuspid Valve

and the Mitral (Bicuspid) Valve.• Tricuspid valve separates the right atrium and

ventricle.• Mitral (bicuspid) valve separates the left atrium and

ventricle.

Heart Valves

• 2 Semilunar Valves– These valves separate the ventricles from the

arteries.– The two semilunar valves are the Pulmonary

Valve and the Aortic Valve.• Pulmonary valve separates the right ventricle from

the pulmonary artery.• Aortic valve separates the left ventricle from the

aorta.

Heart Valves

Important Arteries/Veins of the Heart

• There are several important arteries that take blood away from the heart and important veins that take blood to the heart.– Aorta– Pulmonary Artery & Pulmonary Vein– Coronary Artery– Superior and Inferior Vena Cava

Arteries/Veins of the Heart

Arteries/Veins of the Heart

• Aorta– Largest artery in human body– Blood leaving the left ventricle passes through the

aorta on its way to the bodies other arteries.• Pulmonary Artery & Pulmonary Vein

– Start and end of pulmonary circuit, respectively.– Pulmonary artery takes deoxygenated blood from

the right ventricle and leads it to arterioles and capillaries within the lungs.

– Pulmonary vein takes oxygenated blood from the capillaries and venules within the lungs and leads to the left atrium.

Arteries/Veins of the Heart

• Coronary Artery– Branches off of the aorta.– Supplies the heart’s muscle tissue with the necessary

oxygen.– Blockage of these arteries can lead to angina or heart

attacks.• Superior and Inferior Vena Cava

– Veins that return deoxygenated blood to the heart.– Superior Vena Cava delivers blood from the head and

arms– Inferior Vena Cava delivers blood from the lower

body.

Keeping the Rhythm

• A heart’s rhythm, tempo, or beat rate is controlled by the sinoatrial (SA) node.– This is a bundle of nerves that acts like a pacemaker

for the heart.– Nerve impulses are sent from the SA node to another

node, called the atrioventricular (AV) node.– The AV node then signals the heart muscle tissue to

contract.– The atria contract first, followed by the ventricles

Keeping the Rhythmhttp://a1977.g.akamai.net/f/1977/1448/1d/webmd.download.akamai.com/1448/Anatom-E-Tools/Heart/Heart_Tool.swf

The Functioning Heart

• Here’s a video showing the heart in action and explaining some of it’s anatomy!

• http://www.nhlbi.nih.gov/health/dci/Diseases/hhw/hhw_pumping.html