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
Anatomy of the Heart
• 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.
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 Rhythm
http://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/Disease
s/hhw/hhw_pumping.html