Download Cardiovascular System

Cardiovascular System
Functions of the Cardiovascular
System
• Supply all body tissues with oxygen and
nutrients
• Transport cellular waste products to the
appropriate organs for removal from the
body
Structures
• Heart
– Hollow muscular organ located between the
lungs and above the diaphragm.
– Is a very efficient pump that furnishes the
power to maintain blood flow throughout both
the pulmonary and systemic circulatory
systems.
– Pulmonary- lungs
– Systemic - the body
Heart Cont’d
• Pericardium
– Double-walled membranous sac that encloses
the heart
– Pericardial Fluid lies between the layers to
prevent friction when the heart beats.
Walls of the heart
• 3 layers
– Epicardium – external layer of the heart and
also is part of the inner layer of the pericardial
sac.
– Myocardium – middle and thickest layer,
consists of cardiac muscle
– Endocardium – the inner lining of the heart,
forms the inner surface that comes in direct
contact with blood being pumped through the
heart.
Blood Supply to the Myocardium
• Myocardium must have a continuous
supply of oxygen & nutrients and the
prompt removal of wastes.
• Coronary Arteries and veins supply the
blood needs of the myocardium. If
blood supply is disrupted, the
myocardium in the affected area dies.
This "myocardial death" is painful and is
known as a ___________________.
Heart Chambers
• Heart is divided into left and right sides
• Each side is divided which forms four chambers
• Atria – the two upper chambers of the heart, are
the receiving chambers. All blood vessels coming
into the heart enter here.
• The atria are separated by the interatrial septum.
A septum is a separating wall or partition.
Heart Chambers Cont’d
• Ventricles – the two lower chambers of the heart.
All vessels leaving the heart emerge from the
ventricles.
• The ventricles are separated by the interventricular
septum.
• The ventricles are the pumping chambers.
• The ventricular walls are thicker than the atrial
walls because the ventricles pump the blood
longer distances.
• The narrow tip of the heart is called the cardiac
apex.
Heart Valves
• Control the flow of blood through the heart.
• Tricuspid valve – controls the opening between
the right atrium and the right ventricle.
• Pulmonary valve – located between the right
ventricle and the pulmonary artery.
• Mitral Valve (bicuspid valve) – located between
the L atrium and the L ventricle.
• Aortic semilunar valve – located between the L
ventricle and the aorta.
Systemic and Pulmonary
Circulation
• Systemic circulation –
includes blood flow to
all parts of the body
except the lungs.
• Pulmonary circulation
– the flow of blood
between the heart and
lungs
Right
Ventricle
pumps deoxygenated
blood to the
lungs
Left
Ventricle
pumps
oxygenated
blood to
body parts
(pulmonary
circulation)
(systemic
circulation)
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Circulation Cont’d
• In systemic circulation, oxygen-rich
blood flows out of the heart from the left
ventricle into the arteries.
• Oxygen-poor blood returns to the heart
through the veins and flows into the right
atrium.
Circulation Cont’d
• In pulmonary circulation, blood flows out of the
heart from the right ventricle and through the
pulmonary arteries to the lungs. This is the only
place in the body where arteries carry oxygenpoor blood.
• In the lungs, waste material (carbon dioxide) from
the body is exchanged for oxygen from the inhaled
air.
• The pulmonary veins carry the oxygen-rich blood
into the left atrium of the heart. This is the only
place in the body where veins carry oxygen-rich
blood.
The Heartbeat
• The rate and regularity of the heartbeat is
determined by electrical impulses from
nerves that stimulate the myocardium of the
chambers of the heart.
• Also known as the conduction system, these
electrical impulses are controlled by the
sinoatrial (S-A) note, atrioventricular (A-V)
node, and bundle of His.
Sinoatrial Node
• Also know as the S-A node, is located in the
posterior wall of the right atrium near the entrance
of the superior vena cava.
• Because it establishes the basic rhythm of the
heartbeat, it is called the natural pacemaker of the
heart.
• Electrical impulses from the S-A node start each
wave of muscle contraction in the heart.
• The impulse in the right atrium spreads over the
muscles of both atria, causing them to contract
simultaneously.
• This contraction forces blood into the ventricles.
Atrioventricular Node
• Impulses from the S-Anode
also travel to the
atrioventricular node.
• Also known and the A-V node,
it is located on the floor of the
right atrium near the interatrial
septum.
• The A-V node transmits the
electric impulses on to the
bundle of His.
Bundle of His
• Located within the
interventricular septum.
• Branches of the bundle of His
carry the impulse to the right
and left ventricles and the
Purkinje fibers.
• The Purkinje fibers, causes the
ventricles to contract
simultaneously forcing blood
into the aorta and pulmonary
arteries.
Heart Sounds
• When listening to the heart with a stethoscope,
two distinct sounds are heard. They are called the
“lub-dub” sounds.
• Heard first is the lub sound. This is caused by the
tricuspid and mitral valves closing between the
atria and the ventricles.
• Heard next is the dub sound, which is shorter and
higher pitched. It is caused by the closing of the
semi lunar valves in the aorta and pulmonary
arteries as blood is pumped out of the heart.
Blood Vessels
• 3 major types of blood vessels:
– Arteries – the large blood vessels that carry blood
away from the heart to all regions of the body. It is the
high oxygen content that gives arterial blood its bright
red color.
• Aorta – the main trunk of the arterial system and
begins from the left ventricle of the heart.
• Coronary artery – branches from the aorta and
supplies blood to the myocardium.
• Arterioles – smaller thinner branches of arteries,
carry blood to the capillaries
Blood Vessels Cont’d
• Capillaries serve as the anatomic units connecting
the arterial and venous circulatory systems. They
are the smallest vessels in the body.
• The slower flow of blood through the capillaries
allows time for the exchange of oxygen, nutrients,
and waste materials between the tissue fluids and
the surrounding cells.
Blood Vessels Cont’d
• Veins – form a low-pressure collecting system to
return the waste-filled blood to the heart.
– Have thinner walls and are less elastic than the arteries.
Contractions of the skeletal muscles cause the blood to
flow through the veins toward the heart.
– Have valves that allow blood to flow toward the heart
but prevent it from flowing away from the heart.
– Venules – are small veins that join to form the larger
veins.
Blood Vessels cont’d
• Venae Cavae (singular, Vena Cava)
– Two large veins that enter the heart.
– The superior vena cava – known as the SVC,
brings blood from the upper portion of the
body.
– Inferior vena cava – know as the IVC, brings
blood from the lower portion of the body.
Pulse and Blood Pressure
• Pulse – the rhythmic expansion and contraction of
an artery produced by the pressure of the blood
moving through the artery.
• Blood pressure – a measure of the amount of
pressure exerted against the walls of vessels.
• Systolic pressure – occurs when the ventricles
contract, is the highest pressure against the walls
of the blood vessels.
• Diastolic pressure – occurs when the ventricles are
at rest, and is the lowest pressure against the walls
of the vessels.
•Blood pressure is recorded as systolic
over diastolic. Normal adult reading is
about 120/80 or a little lower.
Circulatory Song
Circulatory
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