ANATOMY and Physiology Case Pre

7/29/2019 ANATOMY and Physiology Case Pre

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ANATOMY AND PHYSIOLOGY

HEART

1. Right Coronary2. Left Anterior Descending3. Left Circumflex4. Superior Vena Cava5. Inferior Vena Cava6. Aorta7. Pulmonary Artery8. Pulmonary Vein

9. Right Atrium10. Right Ventricle11. Left Atrium12. Left Ventricle13. Papillary Muscles14. Chordae Tendineae15. Tricuspid Valve16. Mitral Valve17. Pulmonary Valve

Aortic Valve

Superior Vena Cava

The superior vena cava is one of the two main veins bringing de-oxygenated blood fromthe body to the heart. Veins from the head and upper body feed into the superior venacava, which empties into the right atrium of the heart.

Inferior Vena Cava

The inferior vena cava is one of the two main veins bringing de-oxygenated blood fromthe body to the heart. Veins from the legs and lower torso feed into the inferior venacava, which empties into the right atrium of the heart.

Aorta

The aorta is the largest single blood vessel in the body. It is approximately the diameterof your thumb. This vessel carries oxygen-rich blood from the left ventricle to the variousparts of the body.

Pulmonary Artery

The pulmonary artery is the vessel transporting de-oxygenated blood from the rightventricle to the lungs. A common misconception is that all arteries carry oxygen-richblood. It is more appropriate to classify arteries as vessels carrying blood away from theheart.

Pulmonary Vein

The pulmonary vein is the vessel transporting oxygen-rich blood from the lungs to the

left atrium. A common misconception is that all veins carry de-oxygenated blood. It is
http://www.cardioconsult.com/Anatomy/#Coronary%20Arterieshttp://www.cardioconsult.com/Anatomy/#Coronary%20Arterieshttp://www.cardioconsult.com/Anatomy/#Coronary%20Arterieshttp://www.cardioconsult.com/Anatomy/#Superior%20Vena%20Cavahttp://www.cardioconsult.com/Anatomy/#Inferior%20Vena%20Cavahttp://www.cardioconsult.com/Anatomy/#Aortahttp://www.cardioconsult.com/Anatomy/#Pulmonary%20Arteryhttp://www.cardioconsult.com/Anatomy/#Pulmonary%20Veinhttp://www.cardioconsult.com/Anatomy/#Right%20Atriumhttp://www.cardioconsult.com/Anatomy/#Right%20Ventriclehttp://www.cardioconsult.com/Anatomy/#Left%20Atriumhttp://www.cardioconsult.com/Anatomy/#Left%20Ventriclehttp://www.cardioconsult.com/Anatomy/#Papillary%20Muscleshttp://www.cardioconsult.com/Anatomy/#Chordae%20Tendineaehttp://www.cardioconsult.com/Anatomy/#Tricuspid%20Valvehttp://www.cardioconsult.com/Anatomy/#Mitral%20Valuehttp://www.cardioconsult.com/Anatomy/#Pulmonary%20Valvehttp://www.cardioconsult.com/Anatomy/#Aortic%20Valvehttp://www.cardioconsult.com/Anatomy/#Aortic%20Valvehttp://www.cardioconsult.com/Anatomy/#Pulmonary%20Valvehttp://www.cardioconsult.com/Anatomy/#Mitral%20Valuehttp://www.cardioconsult.com/Anatomy/#Tricuspid%20Valvehttp://www.cardioconsult.com/Anatomy/#Chordae%20Tendineaehttp://www.cardioconsult.com/Anatomy/#Papillary%20Muscleshttp://www.cardioconsult.com/Anatomy/#Left%20Ventriclehttp://www.cardioconsult.com/Anatomy/#Left%20Atriumhttp://www.cardioconsult.com/Anatomy/#Right%20Ventriclehttp://www.cardioconsult.com/Anatomy/#Right%20Atriumhttp://www.cardioconsult.com/Anatomy/#Pulmonary%20Veinhttp://www.cardioconsult.com/Anatomy/#Pulmonary%20Arteryhttp://www.cardioconsult.com/Anatomy/#Aortahttp://www.cardioconsult.com/Anatomy/#Inferior%20Vena%20Cavahttp://www.cardioconsult.com/Anatomy/#Superior%20Vena%20Cavahttp://www.cardioconsult.com/Anatomy/#Coronary%20Arterieshttp://www.cardioconsult.com/Anatomy/#Coronary%20Arterieshttp://www.cardioconsult.com/Anatomy/#Coronary%20Arteries


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more appropriate to classify veins as vessels carrying blood to the heart.

Right Atrium

The right atrium receives de-oxygenated blood from the body through the superior vena

cava (head and upper body) and inferior vena cava (legs and lower torso). Thesinoatrial node sends an impulse that causes the cardiac muscle tissue of the atrium tocontract in a coordinated, wave-like manner. The tricuspid valve, which separates theright atrium from the right ventricle, opens to allow the de-oxygenated blood collected inthe right atrium to flow into the right ventricle.

Right Ventricle

The right ventricle receives de-oxygenated blood as the right atrium contracts. Thepulmonary valve leading into the pulmonary artery is closed, allowing the ventricle to fillwith blood. Once the ventricles are full, they contract. As the right ventricle contracts,

the tricuspid valve closes and the pulmonary valve opens. The closure of the tricuspidvalve prevents blood from backing into the right atrium and the opening of thepulmonary valve allows the blood to flow into the pulmonary artery toward the lungs.

Left Atrium

The left atrium receives oxygenated blood from the lungs through the pulmonary vein.As the contraction triggered by the sinoatrial node progresses through the atria, theblood passes through the mitral valve into the left ventricle.

Left Ventricle

The left ventricle receives oxygenated blood as the left atrium contracts. The bloodpasses through the mitral valve into the left ventricle. The aortic valve leading into theaorta is closed, allowing the ventricle to fill with blood. Once the ventricles are full, theycontract. As the left ventricle contracts, the mitral valve closes and the aortic valveopens. The closure of the mitral valve prevents blood from backing into the left atriumand the opening of the aortic valve allows the blood to flow into the aorta and flowthroughout the body.

Papillary Muscles

The papillary muscles attach to the lower portion of the interior wall of the ventricles.They connect to the chordae tendineae, which attach to the tricuspid valve in the rightventricle and the mitral valve in the left ventricle. The contraction of the papillarymuscles closes these valves. When the papillary muscles relax, the valves open.

Chordae Tendineae

The chordae tendineae are tendons linking the papillary muscles to the tricuspid valvein the right ventricle and the mitral valve in the left ventricle. As the papillary musclescontract and relax, the chordae tendineae transmit the resulting increase and decreasein tension to the respective valves, causing them to open and close. The chordae

tendineae are string-like in appearance and are sometimes referred to as "heartstrings."

Tricuspid Valve

The tricuspid valve separates the right atrium from the right ventricle. It opens to allowthe de-oxygenated blood collected in the right atrium to flow into the right ventricle. Itcloses as the right ventricle contracts, preventing blood from returning to the rightatrium; thereby, forcing it to exit through the pulmonary valve into the pulmonary artery.

Mitral Value

The mitral valve separates the left atrium from the left ventricle. It opens to allow the


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oxygenated blood collected in the left atrium to flow into the left ventricle. It closes asthe left ventricle contracts, preventing blood from returning to the left atrium; thereby,forcing it to exit through the aortic valve into the aorta.

Pulmonary Valve

The pulmonary valve separates the right ventricle from the pulmonary artery. As theventricles contract, it opens to allow the de-oxygenated blood collected in the rightventricle to flow to the lungs. It closes as the ventricles relax, preventing blood fromreturning to the heart.

Aortic Valve

The aortic valve separates the left ventricle from the aorta. As the ventricles contract, it

opens to allow the oxygenated blood collected in the left ventricle to flow throughout thebody. It closes as the ventricles relax, preventing blood from returning to the heart.

The four abnormalities that make up the tetralogy of Fallot include:

Pulmonary valve stenosis. This is a narrowing of the pulmonary valve, the flapthat separates the right ventricle of the heart from the pulmonary artery, the mainblood vessel leading to the lungs. Constriction of the pulmonary valve reducesblood flow to the lungs. The narrowing may also affect the muscle beneath thepulmonary valve. The major issue with tetralogy of Fallot is the degree ofpulmonary valve stenosis, since VSD is always present. If the stenosis is mild,minimal cyanosis occurs, since blood still mostly travels to the lungs. However, ifthe PS is moderate to severe, a smaller amount of blood reaches the lungs,since most is shunted right-to-left through the VSD.


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Ventricular septal defect. This is a hole in the wall that separates the two lowerchambers (ventricles) of the heart. The hole allows deoxygenated blood in theright ventricle blood that has circulated through the body and is en route tothe lungs to replenish its oxygen supply to flow into the left ventricle and mix

with oxygenated blood fresh from the lungs. Blood from the left ventricle alsoflows back to the right ventricle in an inefficient manner. This ability for blood toflow through the ventricular septal defect dilutes the supply of oxygenated bloodto the body and eventually can weaken the heart. This lack of oxygen in theblood causes cyanosis.

Overriding aorta. Normally the aorta, the main artery leading out to the body,branches off the left ventricle. In tetralogy of Fallot, the aorta is shifted slightly tothe right and lies directly above the ventricular septal defect. In this position theaorta receives blood from both the right and left ventricles, mixing the oxygen-poor blood from the right ventricle with the oxygen-rich blood from the left

ventricle.

Right ventricular hypertrophy. This defect occurs if the right ventricle thickensbecause the heart has to pump harder than it should to move blood through thenarrowed pulmonary valve. This restriction to blood outflow causes an increasein right ventricular work and pressure, leading to right ventricular thickening orhypertrophy.

Rarely, some babies who have tetralogy of Fallot will have a hole between their heart'supper chambers (atrial septal defect), as well. When this occurs, the condition is knownas pentalogy of Fallot.

Together, these four defects mean that not enough blood is able to reach the lungs toget oxygen, and oxygen-poor blood flows out to the body.

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ANATOMY and Physiology Case Pre