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68 Cards in this Set
- Front
- Back
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How many chambers does a mammalian heart have? |
4 |
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What are the 4 chambers of the heart? |
The right atrium, the right ventricle, the left ventricle, and the left atrium |
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What are the atrioventricular (AV) valves of the heart? |
On the right, the tricuspid valve. On the left, the bicuspid valve. |
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Where are the semi-lunar valves located? |
They are found between the ventricles and their respective arteries |
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Where is the aortic semi-lunar valve located? |
Near the left ventricle and the aorta |
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Where is the pulmonary semi-lunar valve located? |
Near the right ventricle and the pulmonary trunk |
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What is the first step of the 2 step pump? |
The atrial chambers contract simultaneously |
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What is the second step of the 2 step pump? |
The ventricular chambers contract simultaneously |
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How is systole defined? |
It is a period of time in which contraction is occurring |
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What is atrial systole? |
When the atrial chambers contract |
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What is ventricular systole? |
When the ventricular chambers contract |
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How is diastole defined? |
It is a period in which relaxation is occuring |
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What is atrial diastole? |
When the atrial chambers relax |
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What is ventricular diastole? |
When the ventricular chambers relax |
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What is the cardiac cycle? |
All the mechanical and electrical events in one heart beat |
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In the cardiac cycle, what event is considered the first step? |
Ventricular filling |
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What occurs during ventricular filling? |
Blood is going down into the ventricle |
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When does ventricular filling occur? |
During ventricular diastole |
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During ventricular filling, what valves are closed and which are open? |
During ventricular filling, the atrioventricular valves are open and the semi-lunar valves are closed |
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Why are both semi-lunar valves closed during ventricular filling? |
Because the blood pressure in the arteries is higher than the blood pressure in the ventricles |
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What is atrial systole? |
The period of time when both atrial chambers are contracting simultaneously |
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During atrial systole, the atrioventricular valves continue to stay open. Why is this? |
Because the blood pressure in the atria is higher than the blood pressure present in the ventricles |
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During this period of time, what percentage of blood fills into the ventricles? |
The remaining 30% |
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What is isovolumetric ventricular systole? |
It is the period of time during ventricular systole when the ventricles are starting to contract and blood cannot enter or leave the ventricles. |
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During isovolumetric ventricular systole, what can be said about the AV and semi-lunar valves? |
They are both closed |
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What is ventricular ejection? |
The period of time during ventricular systole when blood is ejected from ventricular chambers to the arteries |
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Halfway through ventricular ejection... |
...blood pressure begins to drop |
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What is isovolumetric ventricular diastole? |
The period of time during ventricular diastole when the ventricles are starting to relax and blood cannot enter or leave the ventricles |
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What does the first heart sound correlate to? |
Closure of the AV valves |
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What does the second heart sound correlate to? |
Closure of the semi-lunar valves |
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What is the function of the sinoatrial (SA) node? |
It is responsible for the rhythmic generation of cardiac action potentials. Therefore, it controls cardiac rate |
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Where is the sinoatrial (SA) node located? |
It the wall of the right atrium, right below the superior vena cava |
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What is the function of the atrioventricular (AV) bundle? |
It slows down the velocity action potentials coming from the SA node prior to entering the AV node. Primarily responsible for ventricular contraction. |
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Where is the atrioventricular (AV) bundle located? |
In the posterior septal wall of the right atrium |
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What is the function of the AV node? |
It transmits cardiac action potentials to the Perkinje Fibers |
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What is the function of the Perkinje Fibers? |
They transmit cardiac action potentials directly to the ventricular muscle tissue |
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What does the P-wave correlate to? |
The period of time when atrial depolarization is occuring |
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What does the QRS complex correlate to? |
The period of time when ventricular depolarization is occuring |
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What does the T-wave correlate to? |
The period of time when ventricular repolarization is occuring |
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What does the PQ interval correlate to? |
The period of time between the end of atrial depolarization and the onset of ventricular delpolarization |
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What does the PQ segment correlate to? |
The period of time from the end of ventricular depolarization to the onset of ventricular depolarization |
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What does the ST segment correlate to? |
The period of time from the end of ventricular depolarization to the onset of ventricular repolarization |
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How is Bradycardia characterized? |
By a slower than average heart beat (< 60 bpm) |
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How is Trachycardia characterized? |
By a faster than average heart beat (> 100 bpm) |
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What do atrioventricular blocks interfere with? |
The AV node |
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How is a primary block characterized? |
The cardiac action potentials are slowed further than normal |
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How is a secondary block characterized? |
The cardiac action potentials cannot make it through the AV node |
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What characterizes a tertiary block? |
Zero cardiac potentials get through and they are generated elsewhere in the heart |
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What is fibrillation? |
When different myocardial cells generate action potentials at different intervals |
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What is an ectopic focus? |
A group of myocardial cells other than the SA node generate cardiac action potentials |
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What is atrial fibrillation? |
Loss of coordinated pumping in the atrial chambers (loss of a P-wave) |
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Is atrial fibrillation fatal? |
No |
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What is ventricular fibrillation? |
The loss of coordinated pumping in the ventricular chambers |
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Can ventricular fibrillation be fatal? |
Yes |
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What is the average cardiac output? |
5250 mL/min |
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What is the stroke volume? |
The volume of blood ejected from the ventricles per contraction |
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What is stroke volume equal to? |
60-70 mL/contraction |
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What is heart rate? |
The number of ventricular contractions per minute |
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What is the average heart rate? |
71-75 contractions/min |
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What is cardiac output equal to? |
Stroke Vol x Heart Rate |
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What is end-diastolic volume? |
The volume of blood present in the ventricle prior to ejection |
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An increase in end-diastolic volume results in... |
...an increase in stroke volume, which cause an increase in cardiac output |
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A decrease in venous return results in... |
...a decrease in ventricular filling, which results in a decrease in end-diastolic volume |
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An increase in the length of diastole results in... |
...an increase in ventricular filling, which results in an increase in end-diastolic volume |
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What is end-systolic volume (ESV)? |
The volume of blood present in the ventricle after ejection |
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An increase in ESV results in... |
...a decrease in stroke volume, which results in a decrease in cardiac output |
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An increase in strength of contraction results in... |
..an increase in ventricular emptying, which decreases ESV, which increases stroke vol |
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What does the Frank-Starling Law of the Heart state? |
That if stretch on a cardiac muscle/cell increases, the force of contraction will also increase |
