Transcript The Cardiovascular System {The Heart}

The Cardiovascular
System
{The Heart}
Chapter 13
Cardiovascular System
a/k/a Circulatory System
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Heart
 Pumps blood
Blood
 Fluid of system
Blood vessels
 Pathway of tubules for blood
 Veins (venules): capillaries  heart
 Vena cava = largest veins
 Arteries (arterioles): heart  capillaries
 Aorta = largest artery
Terminology
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Cardiology: study of the structure, function, &
diseases of the heart
Electrocardiogram (ECG): recording of electrical
changes that accompany heart beat
Cardiac cycle: one heart beat
Systole: contraction of heart muscle
Diastole: relaxation of heart muscle
Stroke volume: the amount of blood pumped out
per beat
Septum: divider
About the heart…
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Located in the mediastinum between lungs
2/3 to the left of midline
Approx. the size of a fist
Apex (tip) points downward
Heart muscle = myocardium
Tissues of the heart
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Membranes (serous fluid in between layers)
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Parietal pericardium: makes up a tough, fibrous cavity that the
heart sits in
Visceral pericardium: covers surface of the heart
**Inflammation of the pericardial membranes = pericarditis
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Muscle
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Epicardium: covers the exterior surface of the heart
Myocardium: bulk of heart muscle
Endocardium: lines the interior cavities of the heart
Cardiopulmonary Resuscitation (CPR)
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Rhythmic compression of the heart
Coupled with artificial respiration it can be
life saving
Works because the heart is sandwiched
between 2 firm surfaces
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Anteriorly, the sternum
Posteriorly, the body of the vertebrae
Conditions/Disorders/Diseases
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Angina pectoris: chest pain (usually precursor to heart
attack)
Myocardial infarction: heart attack; caused by
insufficient blood flow to myocardium; therefore tissue
dies
Heart murmur: valve disorder; causes backflow of blood
Palpitation: irregular heart beat
Phlebitis: Inflammation of a vein
Hypertension: high blood pressure
Cardiovascular Disease
5 types of circulation
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Systemic: blood pumping to body (system)
Pulmonary: blood pumping to the lungs
Coronary: blood pumping to the heart itself
Fetal: circulation of blood to and from the
placenta
Hepatic: blood going through liver to be
filtered and detoxified
Electricity of the Heart
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Sinoatrial (SA) node: the heart’s natural
pacemaker; initiates action potentials;
located in atrial wall
Atrioventricular (AV) node: the heart’s
“back up” pacemaker
Bundle of His & Purkinje fibers carry
impulse throughout heart
When SA node initiates…
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1st: atria contract simultaneously while
ventricles are relaxing
2nd: atria relax while ventricles
simultaneously contract
**This simultaneous contraction and
relaxation results in a lubb-dupp sound
The lubb-dupp of your heart…
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Results from closing of heart valves
Lubb = quiet; systole of atria; diastole of ventricles
(AV valves closing)
Dupp= loud; systole of ventricles; diastole of atria
(semilunar valves closing)
1 heart beat (cardiac cycle) takes about 0.8
seconds
Average resting heart rate = 75 bpm (beats per
minute)
Average stroke volume = 70mL
Components of heart
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Chambers
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Upper
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Vessels
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Right atrium
Left atrium
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Right ventricle
Left ventricle
Pulmonary artery
 Right & left branches
Lower
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Pulmonary
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Pulmonary veins
 2 right & 2 left
branches
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Systemic
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Superior vena cava
Inferior vena cava
aorta
Valves of the heart
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Function: to prevent backflow of blood
Held in place by papillary muscle (in base of chamber) &
chordae tendineae
Lessens chance of oxygenated & deoxygenated blood
mixing
Right AV valve (tricuspid): b/w right atrium & ventricle
Left AV valve (bicuspid/mitral): b/w left atrium & ventricle
Pulmonary semilunar valve: b/w right ventricle &
pulmonary artery
Aortic semilunar valve: b/w left ventricle & aorta
Blood Flow Through Heart
{Pulmonary Circulation}
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Superior vena cava (from upper body) & inferior vena cava
(from lower body) carry deoxygenated blood  right atrium
When right atrium fills, it contracts and forces blood through
the right AV valve (tricuspid)  right ventricle
When right ventricle fills, it contracts and forces blood
through the pulmonary semilunar valve  pulmonary artery
(trunk)
The trunk of the pulmonary artery divides into right and left
pulmonary branches  right and left lungs
In lungs: oxygen and carbon dioxide are exchanged
Blood Flow Through Heart
{Systemic Circulation}
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Pulmonary veins carry oxygenated blood  left
atrium
When the left atrium fills, it contracts and forces
blood through the left AV valve (bicuspid, mitral)
 left ventricle
When the left ventricle fills, it contracts and forces
blood through the aortic semilunar valve  aorta
(ascending, arch, & descending)
Aorta  entire body
Blood Flow Through Heart
{Coronary Circulation}
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Aorta
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Ascending (1st inch)
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Arch (curve)
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Coronary vessels branch off here
Go back to myocardium
3 branches: services left arm, head & neck, and right arm
Descending (remainder)
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Thoracic aorta
Abdominal aorta  iliac arteries in legs
Overview
Superior & inferior vena cava  right atrium
 right AV valve (tricuspid)  right
ventricle  pulmonary semilunar valve 
pulmonary artery (& branches)  lungs
(drop off CO2, pick up O2)  pulmonary
veins  left atrium  left AV valve
(bicuspid, mitral)  left ventricle  aortic
semilunar valve  aorta  body (drop off
O2, pick up CO2)
The Double Pump
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Although we describe the flow of blood as
linear, it is truly a double pump
Both atria contract together
Both ventricles contract together
Myocardium in the right side of the heart is
thinner as it is pumping to the nearby lungs
Myocardium in the left side of the heart is
thicker as it is pumping all over the body
Exceptions to the rule…
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Most of the time
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Veins carry deoxygenated blood (dark reddish
purple blood)
Arteries carry oxygenated blood (bright red
blood)
However,
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Pulmonary arteries & umbilical arteries carry
deO2 blood
Pulmonary veins & umbilical veins carry O2 blood
You must know…
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The flow of blood through the heart
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4 chambers
5 vessels
4 valves (all names)