Transcript Structure of the Heart

Cardiac System
Anatomy & Physiology
Mrs. Micalizzi
Functions of the circulatory system
• Heart pumps and circulates blood to all
parts of the body.
• Blood vessels circulate blood between heart
and cells
• Blood carries oxygen and nutrients to cells
and carries away waste.
• Lymph system returns excess fluids from
tissues and makes lymphocytes.
Heart
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The heart is a hollow, muscular, double pump.
The heart is the shape and size of a closed fist
Located in the thoracic cavity.
The organ is located in the mediastinum with two
thirds of mass to the left of midline and one third
to the right.
• Apex of heart lies on diaphragm
Four Chambers of the Heart
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Right atrium
Left atrium
Right ventricle
Left ventricle
Heart Chambers
• Two upper chambers are called atria
(receiving chambers)-right and left atria
• Two lower chambers are called ventricles
(discharging chambers) -right and left
ventricles.
• Septum-Muscular wall separating heart into
two halves.
Heart Valves
• Four valves permit blood flow in only one
direction
• Tricuspid-at the opening of the right atrium into
the right ventricle
• Bicuspid (mitral) valve- at the opening of the left
atrium into the left ventricles
• Pulmonary semilunar valve –at the beginning of
the pulmonary artery
• Aortic semilunar valve- at the beginning of the
aorta
Sinoartial (SA) or Pacemaker
• Sinoatrial (SA) node or pacemaker sends
out an electrical impulse that regulates the
heart. The impulse spreads out over the
atria, making them contract or depolarize.
This causes blood to flow downward from
the upper atrial chambers
• At the same time, the ventricles are relaxed,
allowing them to fill with blood
Atrioventriclular (AV) Node
• The AV node stimulates the contraction of both
ventricles
• From the AV node, the electrical pulse is carried to
the conducting fibers in the septum, called bundle
of HIS or atrioventricle bundle.
• Then the electrical impulse shoots along the
Purkinje fibers to the ventricles causing them to
contract.
Layers of the Heart
• Pericardium-fibrous, double outer layer that has
pericardial fluid between layers.
• Inner layer is called visceral pericardium or
epicardium. Outer layer called parietal
pericardium.
• Myocardium-cardiac muscle tissue: the wall of the
heart.
• Endocardium-Smooth inner lining of the heart.
Structures leading to and from heart
• Superior and inferior vena cava are blood vessels
that brings deoxygenated blood to the right atrium
from all parts of the body.
• Pulmonary artery takes deoxygenated blood from
the right ventricle to the lungs for oxygen.
• Pulmonary vein brings oxygenated blood from
lungs to left atrium.
• Aorta takes blood from left ventricle to the body
Blood Vessels
• Arteries- carry blood away from the heart to
the arterioles.
• Veins- carry blood toward the heart from the
venules.
• Capillaries-caries blood from the arterioles
to the venules
Structure of The Heart
The End
Questions?