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What is the purpose of the heart?
to pump blood either to the lungs through pulmonary circuit or through the body via the systemic circuit
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Heart....
1. Size?
2. Weight?
3. begins beating how many days after conception?
4. Located where?
- 1. size of your fist
- 2. weighs less than a pound
- 3. 22 days
- 4. thoracic cavity
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What are the 4 points of the perimeter of the heart in order to distinguish a normal size heart from an enlarge heart?
superior left point-at costal cartilage of second rib about an inch lateral to sternum
inferior left point-fifth intercostals space at midclavicar line
superior right point-costal cartilage of third rib connects to sternum
inferior right point-costal cartilage of sixth rib about an inch lateral to sternum
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What is the heart enclosed by?
a serous membrane that has 3 layers (fibrous, parietal, & visceral pericardium)
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What is fibrous pericardium?
outer layer that adheres to the diaphragm & holds the heart in place
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What is parietal pericardium?
adheres to the inner surface of fibrous pericardium & forms parietal cavity that is filled with serous fluid
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What is visceral pericardium?
also called epicardium and lies just above myocardium
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What are the 3 layers of the heart wall?
Epicardium -superficial, comes in contact with epicardium & holds fat
Myocardium - middle muscular layer that contracts to move blood
Endocardium - deepest layer composed of endothelial cells that line the chambers & make the valves
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What are the heart chambers divided into left and right sides by interiorly?
interatrial septum or inventricular septum
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1. Exteriorly, the seperation of atria of ventricles is indicated by what?
2. Ventricle seperation is indicated by what?
- 1. coronary sulcus (crown)
- 2. anterior & posterior interventricular sulcus
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What is the right atrium?
- - top right chamber that has the right auricle
- - receives blood low in oxygen coming from upper & lower body via the superior & inferior vena cava & coronary sinus
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What does the right atrium open into ventricle through?
the right atrioventricular valve (tricuspid)
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What is fossa ovalis?
indicated the area at which the fetal heart had an opening
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What is the right ventricle?
- - a lower right chamber
- - receives blood from right atrium
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When the ventricle contracts, what happens?
it sends blood out to the lungs, first through pulmonary semilunar valve then via the pulmonary artery
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What is the left atrium?
- - upper left chamber
- - receives oxygenated blood coming from the lungs via the pulmonary vein
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What does the left atrium open into the ventricles through?
left atrioventricular valve (mitral/bicuspid valve)
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What is the left ventricle?
- - lower left chamber
- - receives blood from left atrium & forms the apex of the heart with the same cheracteristics as the right ventricle
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What forms the apex of the heart?
left ventricle
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When the left ventricle contracts, what happens?
blood flows through the aortic semilunar valve & then to system circulation via the aorta
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What is the path that the blood takes as it travels through the pulmonary & systemic circulatory paths?
- Blood empties into...
- right atrium
- through...
- SVC, IVC, Coronary Sinus
- Right Atrium
- slightly contracts & blood moves past...
- Tricuspid valve
- into...
- Right ventricle
- right ventricle fills with blood & contracts sending blood out of the heart as it passes through....
- pulmonary semilunar valve
- to the....
- pulmonary trunk
- into the...
- right and left pulmonary artery
- pulmonary arteries
- carry the blood into the...
- lungs
- and heads towards the heart via the...
- right and left pulmonary veins
- blood empties into the...
- left atrium
- filling the chamber slightly contracting as blood passes through the...
- mitral valve
- leaving the chamber
- left ventricle
- filles with blood & powerfully contracts to send blood past the...
- aortic semilunar valve
- into the...
- aortic arch
- aorta
- branches sending blood into all areas of the....
- body (systemic curculation)
- then starts over again...
- back to the heart SVC, IVC, Coronary sinus
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1. What is heart beat?
2. What is the resting heart rate?
- 1. sequence of atrial & ventricular contraction
- 2. 60-80 beats per minute
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What is systole and what is diastole?
Systole - when the heart contracts
Diastole - when the heart relaxes
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What is the endocardium designed to do?
prevent back flow of blood into the chambers
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Each valve has how many cusps?
two or three cusps
- *RAV (tricuspid valve)-3 cusps
- *LAV (bicuspid/mitral valve)-2 cusps
- *Aortic semilunar valve-3 cuspids
- *Pulmonary semilunar valve-3 cuspids
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What are the jobs of the atrioventricular valves?
prevent blood from flowing back into the atria when the ventricles contract
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What is the job of the semilunar valves?
prevent blood from flowing back into the ventricles
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What does closing of the valves cause?
vibrations that can be interpreted as sounds (lub-dub)
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What is the lub and what is the dub?
- lub - closing of AV valves
- dub - produced by closing of semilunar valves
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To listen to each valve, what is used to place at different locations when checking for heart beat?
stethoscope
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Dense connective tissue lies throughout the heart and serves the following functions...
- 1. Anchors valves
- 2. prevents over dialation of valves
- 3. serves as insertion points for cardiac muscle
- 4. prevents direct electrical impulse travel from atria to ventricles
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1. How does the heart generates electrical impulse and conduct rhytmic contractions?
2. what are the components?
- 1. by the conduncting system:
- cardiac muscles generate impulses that signal rhythmic contractions independent of nervous control controlling the sequence at which the chambers contract-thus stablishing the basic heart rate
2. sinoatrial node, internodal fibers, atrioventricular node, atrioventricular bundle (bundle of his), bundle branches, purkinje fibers
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What is the sinoatrial node?
starting point, pace maker, sends out 70-80 impulses per minute
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What are internodal fibers?
fibers that transmit the impulse between SA and AV node
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What is the atrioventricular (AV) node?
heart cells where signal is delayed so ventricles fill. When the SN stops working, AV node takes over.
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What is the atrioventricular bundle (bundle of his)?
heart cells that carry an impulse to the interventricular septum
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What are bundle branches?
heart cells that carry an impulse from interventricular septum & become pirkinje fibers
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What are purkinje fibers?
long barrel like muscle cells specialized for conduction
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What the innervation of the heart?
heart is altered by nervous system control where the nerve fibers that reach the heart are parasympathetic & sympathetic fibers
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What is the heart blood supply?
heart muscles require its own set of blood vessels to nourish the cardiac tissue
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What is coronary artery disease?
caused by atherosclerosis (accumulation of fatty deposits) with the arteries supplying the heart muscle becoming clogged causing chest pain
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Howe does a heart attack occur?
when the cardiac cells die (myocardial infarction)
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What is coronary bypass surgery?
restores blood supply to heart tissue
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What is silent ischemia?
painless silent fatal heart attack
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What is heart failure?
weakening of the heart because it cannot pump at a rate adequate enough to keep up with the body's oxygen demand resulting from a heart attack, improper filling of ventricles, or congestive heart failure
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What is congestive heart failure?
enlargement of the heart causing pumping ineffiency with the right ventricle somtimes enarging due to hgih pressure in the pulmonary circuit
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What are the disorders of the conduction system?
ventricular fibrillation - random firing of electrical impulses allow for improper filling of ventricles, can cause cardiac arrest
atrial fibrillation-random stimulation of AV node signals by multiple signals in atrial myocardium ventrals causing ventricles to contract quickly & irregurly potentially forming blood clots & the blood clots can cause strokes
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