Download The Pumping Heart

The Pumping Heart
• The heart is enclosed in a double-walled sac
called the pericardium.
• The functions of the pericardium are:
1. Protects the heart
2. Anchors the heart
• The heart is divided into 4 chambers.
1. Right Atria (top)
2. Left Atria (top)
3. Right Ventricle (bottom)
4. Left Ventricle (bottom)
• The beating and rhythm of the heart are
controlled by the sinoatrial node, which is
sometimes called the pacemaker of the heart.
.The SA node is a small mass of tissue in the
upper wall of the right atrium.
.The heart of a healthy adult at rest beats about
70 times a minute.
• The heart has two muscular pumps that
operate side by side.
1. Pulmonary Circulation
The pulmonary pump is on the right
side.
It receives blood from the body and
circulates it to the lungs.
• 2. Systemic Circulation
The systemic pump is located on the
left side of the body.
It receives blood from the lungs and
pumps it to the rest of the body.
• Pulmonary arteries take blood away from the
heart.
• Pulmonary veins take blood to the heart.
• The "lubb" sound is produced when the atrioventricular valves in
the heart close. These valves are between the atria and ventricles
• . The "dupp" sound is created when the semilunar valve closes.
These valves are located between the aorta and pulmonary artery.
These valves are at the top of the heart and lead
to the arteries that carry blood to either the
lungs or the body.
The "lubb" is the first heart sound and softer.
The "dupp" sound is shorter and louder than
the "lubb" sound. This is because the cusps of
the semilunar valves are more rigid than the
atrioventricular valves (mitral and tricuspid).
• An abnormal heart sound is called a murmur.
• Murmurs are caused by backflow of blood
through a damaged valve or flow of blood
through an abnormally narrowed valve.
• Blood with waste products (deoxygenated
blood) returns to the right atrium thorugh the
superior and inferior vena cavae.
• This blood is dull red because it has little
oxygen in it.
When the atrium contracts, the blood moves
through the tricuspid valve into the right
ventricle.
When the ventricle contracts, blood is pumped
through a valve to the pulmonary arteries and
then to the lungs, where it releases carbon
dioxide and picks up oxygen.
• When oxygen enters the blood from the
alveoli, the oxygen binds to the hemoglobin
and the blood turns bright red.
• The blood returns through the pulmonary
veins to the left atrium. It then moves
through the bicuspid valve into the left
ventricle.
• The left ventricle pumps the blood into the aorta
(the heart’s major artery) and the aorta branches
off into the rest of the body.
• No other muscle in the human body has the
strength and endurance of the heart muscle.
• The heart is 1/200 of the bodies weight but
requires 1/29 of the body’s blood to function
because it has a very high metabolic rate.
• The coronary arteries supply the nutrients
necessary to keep the heart beating.
• If these arteries become blocked, a heart
attack may occur.
• Because the blood remains confined in the blood
vessels, humans are said to have a closed
circulatory system.
• Creatures like insects, have an open circulatory
system . Insects blood is sucked into the heart
through small holes in its sides and pumped out
through holes in the front.
• Insects have no true blood vessels and their
blood is mainly used to remove wastes, but
not for oxygenation.
• Heart Problems
A number of things can affect the heart and its
functioning:
Smoking
Air pollution
Stress
Lack of exercise
Advanced aging may result in hardening of the
arteries.
Congestive heart failure occurs when the
pumping ability of the heart is insufficient to
circulate the blood throughout the body.
Congenital heart defects account for a large
percentage of infant deaths.