Download The Cardiovascular System

The Cardiovascular System
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Organization of the Cardiovascular System: Circuits
Pulmonary Circuit
Systemic Circuit
Carries blood to &
Carries blood to &
from the lungs
from the body
Right side of heart →
Left side of heart →
pumps blood to lungs
pumps blood to body
Blood alternates between
pulmonary circuit &
systemic circuit
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Location of the Heart
Muscular organ ~ size of fist
Thoracic cavity
Apex → points toward left side of body
Base → points toward right shoulder
Medial to R/L lungs
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Major Functions of the Heart
• keeps oxygen poor blood separate from oxygen rich blood
• keeps blood flowing in one direction
• generates blood pressure
• moves blood throughout body
• serves as an endocrine gland (ANP/ANH → BP
regulation)
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Layers of Heart Wall
Endocardium – innermost layer → simple squamous epithelium (endothelium)
Myocardium – thickest layer → cardiac muscle
Epicardium – outermost layer → also part of the pericardium
epicardium
myocardium
(heart wall)
endocardium
heart chamber
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Pericardium
Fibrous pericardium – outermost layer
• anchors & protects heart
Serous pericardium – 2 layers
• parietal layer
“heart”
pericardium
• visceral layer = epicardium
Pericardial cavity – fluid reduces friction
fibrous pericardium
serous
pericardium
parietal layer
pericardial cavity
visceral layer
(epicardium)
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Chambers of the Heart
Four Chambers
• Two Atria → superior
• divided by interatrial septum
• receiving chambers
• Two Ventricles → inferior
• divided by interventricular
L
A
R
A
septum
• pump blood out of heart
R
V
L
V
interventricular septum
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Valves of the Heart
Four Valves → ensure 1-way flow of blood
• Two Atrioventricular Valves
• separate atria from ventricles
• Two Semilunar Valves
• separate ventricles from major
arteries
Which valves are the AV valves? SL valves?
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Valves of the Heart
Atrioventricular Valves
1) Right AV valve (tricuspid valve)
2) Left AV valve (bicuspid, mitral valve)
Semilunar Valves
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3) Pulmonary SL valve
4) Aortic SL valve
4
2
1
2
1
4
3
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Pathway of Blood Through the Heart Chambers & Valves
R atrium
1
L atrium
R (AV) valve
L (AV) valve
R ventricle
L ventricle
3
3
2
2
Pulmonary
SL valve
Aortic
SL valve
lungs
body
4
4
1
(pulmonary circuit) (systemic circuit)
http://www.mayoclinic.com/health/circulatory-system/MM00636
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Pulmonary Circuit
Systemic Circuit
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Heart Sounds
Heart sounds (“lub-dup”)
• 1st sound - AV valves closing (louder/stronger sound)
• 2nd sound - SL valves closing (shorter/sharper sound)
• Can distinguish sounds of 4 valves
Heart murmurs
• ineffective, “leaky”
valves
• allows backflow of blood
• clicking/swishing sound
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Great Vessels of the Heart
Aorta
Superior Vena Cava
Arteries
Pulmonary
trunk
• Pulmonary trunk
• carries O2 poor blood to lungs
• Aorta
• carries O2 rich blood to body
Pulmonary
Veins
Veins
• Superior/Inferior Vena Cavae
• carry O2 poor blood to heart
• Pulmonary veins
• carry O2 rich blood to heart
Inferior Vena Cava
Why is the pulmonary trunk an artery? Why is it blue?
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Pathway of Blood
Right atrium → tricuspid
1
valve → right ventricle
3
Right ventricle → pulmonary2semilunar valve → pulmonary trunk → lungs
4
Lungs → pulmonary
veins → left atrium
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Left atrium → bicuspid
valve → left ventricle
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Left ventricle → aortic semilunar
valve → aorta
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Aorta → systemic
circulation
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Group question: Why is the left ventricle larger than the right ventricle?
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