Heart
THE HEART IS TWO PUMPS: LEFT AND RIGHT
LEFT PUMP:From lungs to bodyRIGHT PUMP: From body to lungs
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The Pulmonary and Systemic Circuits
Figure 18.13
Heart Chambers• Each pump has two types of chambers:
ATRIUM and VENTRICLE
Left Atrium
Left Ventricle
Right Atrium
Right Ventricle
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Blood Flow• Deoxygenated blood from body enters
the RA through the superior and inferior vena cava.
• It pours through the TRICUSPID (RIGHT AV) VALVE into the right ventricle.
• Right atrium contracts, pushes blood into the right ventricle ventricle expands, then contracts with force.
• To prevent the blood from going back up into the atrium, need a valve.
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Blood Flow• Blood comes from the superior or inferior vena cava, into the right
atrium, past the tricuspid valve, into the right ventricle. It then goes past the pulmonary semilunar valve, and into the pulmonary arteries.
IVC
Pulmonary arteriesSVC
RA
RV
Tricuspid valve
Pulmonary Semilunar valve
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VALVES
• Valves are like a swinging door that can only open one direction. But you can push against this door, since it’s only tissue.
• But if you tie a rope to the doorknob, it won’t be able to go the wrong way. The ropes are called CHORDAE TENDONAE, (“heart strings”) which are anchored to pieces of myocardium called PAPILLARY MUSCLES.
• The contraction of the papillary muscles pulls on the chordae tendonae to close the valves, preventing a PROLAPSED VALVE (turned inside out).
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Figure 18.9a
Valves
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Function of the Atrioventricular Valves
Figure 18.9b9
Heart Valves – Valve Structure
Figure 18.8a10
Trabeculae carneae (spongy meat)
• Trabeculae carnae are masses of irregular spongy tissues which project from the inner surface of the right and left ventricles.
• The purpose of the trabeculae carneae is to prevent suction that would occur with a flat surface and thus impair the heart's ability to pump efficiently.
• The trabeculae carneae also serve a similar function to papillary muscles in that their contraction pulls on the chordae tendineae, preventing prolapsed mitral (bicuspid) and tricuspid valves.
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Trabecula Carnae
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What is an artery?
• An artery is a vessel that carries blood AWAY from the heart. It does not matter if it is oxygenated or deoxygenated blood.
• A vein is a vessel that carries blood TOWARD the heart. It does not matter if it is oxygenated or deoxygenated blood.
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Blood FlowWith the ventricular contraction, blood can go only one way: into the PULMONARY ARTERY (one of the few arteries with deoxy blood). When the ventricles relax, the PULMONARY SEMILUNAR VALVE closes to prevent blood from going from the pulmonary artery back into the right ventricle.
IVC
Pulmonary arteries
Pulmonary veins
SVC
RA
RV
Tricuspid valve
Pulmonary semilunar valve
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Function of the Semilunar Valves
Figure 18.10a, b15
Blood Flow
• When the ventricles relax, the PULMONARY SEMILUNAR VALVE closes to prevent blood from going from the pulmonary artery back into the right ventricle.
• Do the semilunar valves have a chordae tendonae?
• No; the blood is not being forced back (with a contraction), it just falls back with gravity, so there’s not as much pressure.
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Blood Flow• Blood then goes into lungs, gets oxygenated, and returns on the left
side through the PULMONARY VEINS (one of the few veins with oxy blood), into the LEFT ATRIUM.
LA
LV
Pulmonary arteries
Pulmonary veins
Tricuspid valveBicuspid (mitral) valve
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Lungs
Blood FlowFrom the LEFT ATRIUM, it goes through the MITRAL VALVE (BICUSPID VALVE) into the LEFT VENTRICLE(there are also chordae tendonae here), which contracts. Therefore, the left ventricle is the chamber which is responsible for generating the largest pressure upon contraction.
LA
LV
Pulmonary arteries
Pulmonary veins
Tricuspid valveBicuspid (mitral) valve
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Lungs
Mitral Valve
• The mitral valve gets its name from being the shape of a Bishop’s hat, called a mitre.
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Blood Flow• The blood then goes past the AORTIC SEMILUNAR VALVE, into
the AORTA, and out to the body.
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LA
LV
IVC
Pulmonary arteries
Aorta
Pulmonary veins
SVC
RA
RV
Tricuspid valveBicuspid valve
Pulmonary semilunar valve
The semilunar valves are located between the ventricles and the great arteries.
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VALVES: “Try before you Buy”
• TRICUSPID VALVE• BICUSPID VALVE (MITRAL VALVE) • PULMONARY SEMILUNAR VALVE • AORTIC SEMILUNAR VALVE
• Structures associated with tricuspid and bicuspid valves– CHORDAE TENDONAE– PAPILLARY MUSCLES
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Blood FlowDeoxy blood sup/inf vena cava R atrium tricuspid valve R ventricle pulmonary semilunar valve pulmonary artery lungs pulmonary veins Left atrium mitral (bicuspid) valve Left ventricle aortic semilunar valve aorta rest of body.
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LA
LVIVC
Pulmonary arteries
Aorta
Pulmonary veins
SVC
RA
RV
Tricuspid valveBicuspid valve
Pulmonary semilunar valve
Aortic semilunar valve
STRUCTURES TO KNOW ON THE SHEEP HEART • A. myocardium• B. endocardium• C. visceral pericardium • 1. apex • 2. interventricular septum (IV septum)• 3. left ventricle • 4. right ventricle • 5. right atrium • 6. left atrium • 7. chordae tendinae • 8. papillary muscles • 9. tricuspid valve • 10. bicuspid (mitral) valve • 11. trabeculae carni• 12. aortic semilunar valve
Apex
Myocardium (meaty areas of brown muscle
Endocardium (inside all chambers where blood touches)
Visceral pericardium (outer shiny surface of heart)
What LAYER of tissue is this?
Apex
What CHAMBER is this? Right ventricle
What CHAMBER is this? Right atrium
What CHAMBER is this? Left atrium
What CHAMBER is this? Left ventricle
Apex
Atrial septum
Interventricular Interventricular septumseptum
Mitral (bicuspid) valve
Apex
Tricuspid valve
Mitral Mitral (bicuspid) (bicuspid) valvevalve
Cordae Cordae tendonaetendonae
Papillary Papillary musclesmuscles
Aortic Aortic semilunar semilunar
valvevalve
Trabeculae Trabeculae carnaecarnae
Aorta
Superior vena cava
Pulmonary artery
STRUCTURES TO KNOW ON THE HUMAN HEART
• A. myocardium• B. endocardium• C. visceral pericardium • D. pulmonary trunk• E. pulmonary veins (there are four) • F. pulmonary arteries • G. right coronary artery • H. left coronary artery • I. Circumflex artery• J. posterior interventricular artery • K. anterior interventricular artery
L. Right brachiocephalicM. Right subclavianN. Right common carotidO. Left common carotidP. Left subclavian
Visceral pericardium (outer shiny surface)
Myocardium
Endocardium
STRUCTURES TO KNOW ON THE HUMAN HEART • 1. apex • 2. Interventricular septum (IV septum)• 3. left ventricle • 4. right ventricle • 5. right atrium • 6. left atrium • 7. atrial septum • 8. chordae tendinae • 9. papillary muscles • 10. trabeculae carni• 11. mitral valve (bicuspid valve) • 12. tricuspid valve • 13. aortic semilunar valve• 14. pulmonary semilunar valve • 15. aorta • 16. superior vena cava • 17. inferior vena cava
Pulmonary trunk
Left coronary artery
Right coronary
artery
Superior vena cavae
Aorta
Right Atrium
Left Atrium
L. Pulmonary artery
Apex
Right Auricle (ear shaped)
Posterior view of heart
Superior vena cavae
Inferior vena cavae
Trachea
Aorta
Right Atrium
Left Atrium
Pulmonary veins
Pulmonary veins
Posterior interventricular artery
Coronary sinus
Anterior interventricular artery
Left Atrium
Left Ventricle
Interventricular septum
Right Atrium
Right Ventricle
Atrial septum
Right Auricle (ear shaped)
Pulmonary semilunar valve
Papillary muscles
Cordae tendonae
Trabeculae carnae
Mitral (bicuspid) valve
Tricuspid valveAortic semilunar valve (look deep under here)
Look up here to see aortic semilunar valve
Pulmonary semilunar valve
R. Coronary artery
Pulmonary veins
L. Coronary artery
Anterior interventricular artery
Circumflex artery
Aorta
Pulmonary trunk
Left subclavian artery
Left common carotid artery
R. Brachiocephalic artery
R. common carotid artery
L. Pulmonary artery
R. subclavian artery
Superior vena cava
Trachea
EsophagusInferior vena cava
Fetal Circulation
FETAL CIRCULATION
• Umbilical vein carries oxygenated blood from the placenta; it is the VESSEL where blood is most highly oxygenated.
• Right atrium is the CHAMBER where blood is most highly oxygenated
• Foramen ovale is the hole between the fetal atria
• Ductus arteriosus is the connection between the pulmonary artery and the aorta
Fetal Circulation
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