Download The Electrocardiogram

The Heart
Chapter
The Heart Is a Double Pump
Delivers Oxygen and nutrients to the
tissues
Removes carbon dioxide and waste from
the tissues
Location and Design
Hollow muscular organ located within the
center of the chest in the mediastinum.
60% is located to the left of midline
5”X3.5” approximately the size of a
clenched fist.
Shape
Oval type shape
Base - is the top of the
heart
Apex - is the bottom
of the heart
•Organ Layers
The heart moves freely and can change its
stroke volume (SV) and twist to eject blood
friction free.
Pericardium
Surrounds:
• Heart
• Great vessels
•3 Layers of the Heart Muscle
Epicardium
The outer most layer. Is contiguous with the visceral
pericardium
Myocardium
The actual muscle of the heart. It is the thickest.
Responsible for contraction (more later)
Endocardium
The inner lining of the heart, made of epithelial cells
In contact with the blood in the chambers.
Myocardial Muscle
Specialized found only in the heart
Striated like skeletal
Electrical properties like smooth muscle
Chambers
Double pump.
Right and left sides.
4 chambers.
2 atria - upper chambers deliver blood to
ventricles.
2 ventricles- lower chambers pump blood out of
the heart.
Valves of the heart
Designed to promote forward flow
Valves close to prevent backflow
Made of fibrous tissue that has grown out of
the walls of the heart
2 types:
Atrioventricular (AV) (separate chambers)
Semilunar (separate chamber/vessel)
AV Valves
The two valves that separate the atrial
chambers are called AV or atrioventricular
valves.
The Bicuspid or Mitral valve is between the
left atrium and ventricle
Tricuspid is between the right atrium and
ventricle
Semilunar valves (half moon)
Both arteries that leave the heart have these
valves separating them from the ventricles
Pulmonary
Aortic
Are between the two ventricular chambers
and the large arteries that carry blood away
from the heart.
They each have 3 leaflets