Cardiovas
cular
System
DAY 1 – C H A P T E R 1 5
Overview
Vascular System
blood circulates
inside closed
transport systems
Anatomy of the Heart
General
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Size: approximately the size of a person’s fist
Location: in the mediastinum - the cavity in
the center of the chest
Coverings: Pericardium
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Double layered sac
Contains roughly half an ounce of
pericardial fluid to reduce the friction of the
beating heart
Parietal layer: fibrous membrane; outer
layer
Visceral layer: serous membrane; also called
the epicardium; attached to myocardium
Heart Wall
 Myocardium: heart
muscle; thicker on left
side of the heart
 Endocardium: lining
of heart chambers;
endothelial tissue
continuous with the
lining of the blood
vessels
Chambers of the Heart
Atria
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2 upper chambers of heart; thin walls, smooth inner surface
Responsible for receiving blood
Right atrium receives deoxygenated (oxygen poor) blood from the body
through the superior and inferior vena cava
Left atrium receives oxygenated (oxygen rich) blood from the lungs through
the pulmonary veins
Ventricles
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2 lower chambers of the heart; thicker walls, irregular inner surface
Contain papillary muscles and chordae tendineae (prevent heart valves from
turning inside out when ventricles contract)
Left wall 3x as thick as right wall; forms apex of heart
Responsible for pumping blood away from the heart
Right ventricle sends deoxygenated blood to the lungs via the pulmonary
arteries
Left ventricle sends oxygenated blood to all parts of the body via the aorta
Chambers of the Heart (ctd.)
Accessory
Structures
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Septum: muscular
wall dividing the
heart into right
and left halves
Heart valves:
prevents the
backflow of blood
Papillary muscles
Chordae tendineae
Great Vessels
 Superior and inferior vena cava: receive deoxygenated
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blood from all parts of the body
Coronary sinus: returns deoxygenated blood from the
myocardium to the right atrium
Pulmonary arteries: carry deoxygenated blood to the
lungs from the right ventricle
Pulmonary veins: carry oxygenated blood to the left
atrium from the lungs
Aorta: carries oxygenated blood to distribute to all
parts of the body
Blood Vessels
 Types of Blood Vessels:
 Arteries
 Arterioles
 Capillary
 Venules
 Veins
beds
Anatomy of Blood Vessels
Three coats (tunics):
1. Tunica intima: endothelium
lines the interior of vessels;
decreases friction as blood
flows
2. Tunica media: smooth muscle
& elastic tissue (dilates &
constricts vessels)
3. Tunica externa: fibrous
connective tissue on outside
supports and protects vessels
Arteries
 Carry blood AWAY from the heart
 All BUT pulmonary arteries carry
oxygenated blood
 Aorta: largest artery; 1 inch in diameter
 Arterioles: smallest arteries
 Coronary arteries: most important;
supply blood to the heart muscle
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Left and right main coronary artery
Left coronary artery - left anterior descending, left
circumflex branch
 Right coronary artery - right atrium and right
ventricle
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Veins
 Carry blood TOWARD the
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heart
All BUT pulmonary veins carry
deoxygenated blood
Layers much thinner, less
elastic
Series of internal valves that
work against the flow of gravity
to prevent reflux
Superior and inferior vena
cava: largest veins
Venules: smallest veins
Vericose Veins
 People stand for long
periods of time 
inactivity or pressure on
veins
 Blood pools in feet and
legs
 Valves weaken  veins
become twisted & dilated
 Treatment: compression
stockings, exercise, laser
treatment, surgery
Capillaries
 Tiny, microscopic
vessels
 Walls one cell layer
thick
 Function: to transport
and diffuse essential
materials to and from
the body’s cells and
the blood
Arteries
Capillaries
Veins
• Blood away
from heart
• Thicker walls
• Withstand high
pressure
• Walls 1-cell
thick
• Exchange gases
between blood
and tissue cells
• Blood back to
heart
• Thinner walls
• Low pressure
• Large lumen
• Valves: prevent
blood backflow
• Skeletal muscles
enhance venous
return
Vital Signs
 Pulse: expansion &
recoil of an artery
with each beat of
left ventricle
 Pressure points (eg.
carotid artery, radial
artery)
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Normal resting: 70-76
beats/min
Cardiovascular
System
DAY 2
Cardiovascular Circuits
 Pulmonary circuit: transport of blood from the right
side of the heart to the lungs and then back to the left
side of the heart
 Systemic circuit: transport of blood from the left side
of the heart to all parts of the body and then back to
the right side of the heart
 Coronary circuit: transport blood from the left side of
the heart to the heart tissues and back to the right side
of the heart
Heart Valves
 Tough fibrous tissue between the heart chambers and major
blood vessels of the heart
 Gate-like structures to keep the blood flowing in one
direction and to prevent regurgitation or backflow of blood
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Atrioventricular valves: when ventricles contract, blood is forced
upward and the valves close
Tricuspid valve: between the right atrium and the right ventricle
Bicuspid/mitral valve: between the left atrium and the left ventricle
Semilunar Valves: 3 half moon pockets that catch blood and balloon
out to close the opening
Pulmonary semilunar valve: between the right ventricle and the
pulmonary arteries
Aortic semilunar valve: between the left ventricle and the aortic
arch/aorta
How the Heart Works
 Each heartbeat has two phases, systole when the heart pumps and
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diastole when the heart chambers fill with blood.
Blood enters the right atrium from the body via the vena cava.
It travels through the tricuspid valve into the right ventricle.
A systolic heartbeat sends the blood through the pulmonary valve,
which separates the right ventricle and the pulmonary artery, to the
lung.
In the lung, oxygen is delivered to red blood cells and carbon dioxide, a
waste product of metabolism, is removed.
The oxygenated blood returns to the left atrium where it travels
through the mitral valve into the left ventricle.
The systolic heartbeat also causes the left side of the heart to contract
and send the blood through the aortic valve that separates the left
ventricle and the aorta.
Blood passes through the aorta to the body delivering oxygen to the
body's tissues.
Heart Sounds
 When the AV (atrioventricular) and semilunar valves
close, they make the sound heard as “lub-dub”
(auscultated with stethoscope)
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First sound (S1): ventricles are contracting and forcing blood to
the lungs and entire body (AV valves closing)
Second sound (S2): atria are contracting
and the semilunar valves are closing
 Abnormal heart sounds = murmur;
valve pathology (M1, M2)
Vital Signs
 Blood pressure:
pressure
of blood on inner walls
of blood vessels
 Systolic pressure: peak of
ventricular contraction
 Diastolic pressure:
ventricles relaxed
 Written:
Systolic/Diastolic
 Normal: 100-140;
60-90
Homeostatic Imbalances
 Hypertension: high blood pressure (>140/90)
 Circulatory shock: acute hypotension
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Blood loss
– artery walls thicken due to fatty
deposits (plaques)
 Atherosclerosis
Bypass Surgery
 One of the most common
surgeries performed
 During surgery, a blood
vessel is removed or
redirected from one area of
the body and placed
around the area or areas of
narrowing in order to
"bypass" the blockages and
restore blood flow to the
heart muscle.
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This vessel is called a graft.
These substitute blood vessels
can come from your chest,
legs, or arms.
Stent Procedure
 A stent is a wire mesh
stainless steel tube that
holds an artery open
and keeps it from
closing again.
 It becomes a permanent
part of the artery.
How is it Done?
 The doctor will insert a tiny, flexible plastic tube called
a catheter through an artery in the groin, leg, or arm.
 A special dye is injected so blood flow through the
arteries is visible on monitors.
 The doctor moves a balloon catheter, and then a stent,
to the site of the blockage.
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The balloon is inflated and stretched wide against the artery
walls, which opens the blockage.
Then the balloon is deflated and taken out, leaving the stent in
place.
Congenital Heart Disease
 Defects in the heart that occurred during embryologic
and fetal development
 Involves defective communication between the
chambers, malformation of valves, and malformation
of septa
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Cyanotic: inability of individual to get adequate blood
oxygenation due to extensive cardiac abnormalities that cause
blood to be shunted away from lungs
 Some association with pregnant
mother having German measles
(rubella)
Congestive Heart Failure
 Progressive weakening of heart
 Low heart efficiency 
circulation inadequate to meet
tissue needs
 Caused by:
 Coronary atherosclerosis
 Persistent high blood pressure
 Multiple heart attacks – scar
tissue