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40 Cards in this Set
- Front
- Back
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What is the significance of the Auricles of the atria? |
This is where clots are more likely to occur due to stagnant blood or arrhythmias |
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What is the electrical conduction pathway thru the heart? |
1)AP in SA node 2) Atria Depol (Bachmans) 3) AV node delays conduction to allow atria to contract/ventricles to fill 4) Bundle of his 5) Bundle Branches 6) Purkinje fibers |
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How much blood does the atria pump? |
Roughly 15-20% |
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Electrical activity and ECG reading
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P wave - Atrial Depol QRS - Ventricular Contraction T wave - ventricular depolarization |
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What valves are open during the P wave |
Tricuspid and mitral valve to allow ventricle filling |
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What valves are open during the QRS wave
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Aortic and pulmonary valves are open to decrease movement of blood into the atria and inc movement of blood into the aorta and pulmonary artery |
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What valves are open during the T wave |
Tricuspid and mitral valves are opening and aortic and pulmonary valves are closing |
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The coronary arteries receive most of their blood during the __________ phase of the cardiac cycle. |
Diastolic |
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Location and supply of the right coronary artery
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Arises from the R AL surface of the aorta and passes between the auricular appendage of the right atrium and pulmonary trunk. Supplies: R Atrium, Ventricle, bottom of left ventricle and back of septum |
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Location and supply of the left coronary artery |
Originates from the L AL aspect of the aorta and spilts into two branches: left anterior descending and circumflex arteries. LAD Supplies: front and bottom of the left ventricle and front of septum CFA Suppies: Left atrium and the side and back of the left ventricle |
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What artery blockage may cause arrhythmias and affect the SA Node? |
Right Coronary Artery |
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Why is the LAD artery the "Widow Maker" |
Because the body relies heavily on that artery to supply blood to the entire body |
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Where are the baroreceptors located and their purpose? |
Aortic arch and Carotids They sense stretch and when they hit a certain amount of pressure they push blood flow to the head |
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What happens in regards to baroreceptors with bed rest? |
The BR are not stretching and the threshold level lowers. The BR stretch less and when you stand you get less blood to the head because it rushes down toward your feet |
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What happens in regards to baroreceptors with Long standing HBP? |
With HBP the BR adjust to that BP and stretch. Once placed on medication, pt may start to feel light headed because the adjusted threshold of stretch is too high for their new lower BP |
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When baro receptors sense a drop in BP how should the body respond? |
Stimulate sympathetic fibers which will increase HR, SV and cause vasoconstriction |
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Baroreceptor response to HBP |
Parasympathetic response --> HR lowered and peripheral vasodilation |
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Baroreceptor response to LBP |
Sympathetic response --> HR Inc and peripheral vasoconstriction |
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What is the most prominent type of adrenoceptor in the heart? |
Beta 1 |
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What is the most prominent type of adrenoceptor in the lungs? |
Beta 2 |
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Where are Alpha receptors found? |
Primarily in the periphery |
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What happens when you block beta receptors? |
You will get a net result of parasympathetic activation which will then result in decreased HR |
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How is HR regulated? |
-SA node (60-100 BPM) -Symp and Parasymp fibers can alter the SA node rate and contractility -Chronotropic effect (alters rate) + will inc hr // - will decrease hr -Ionotropic (alters contractility) + Inc contractility // - dec contractility |
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Describe the Ionotropic effect on HR |
Stimulation acts on Beta receptors in the myocardium Pos Ionotropic = Sympathetic Stimulation which will vasodilate the coronary artery and inc contractility (promote influx of Ca available to sarcomeres) Neg Ionotropic = Parasympathetic Stimulation which will vasoconstrict the coronary artery and decrease contractility |
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Describe Parasympathetic |
Input from R and L vagus nerve Vagus nerve stimulation is from acetylcholine and is cardio inhibitory --Dec HR --Dec BP |
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Describe Sympathetic |
Arises from the sympathetic trunk in the neck Releases catecholamines (epi and norepi) which interact with B-adrenergic receptors on the cardiac cell membrane Sympathetic stimulation is cardio excitatory --Inc HR --Inc BP --Inc Contractility |
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What would Aortic Valve regurgitation cause? |
Decrease CO Blood flows back into the left ventricle causing the ventricle to work harder to pump the blood out which can lead to ventricular hypertrophy Dec blood to coronary arteries |
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What would a mitral valve stenosis cause? |
Decreased Cardiac output Left ventricle receives less blood Blood can back up to the lungs after pooling in the atria |
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Transmural infarction vs non transmural
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Transmural goes thru all three layers -Endocardium -Myocardium -Pericardium |
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What are the 4 areas to listen to the heart sounds? |
Aortic Area - R 2nd intercostal space, lateral to sternum Tricuspid Area - Inf L Sternal margin Pulm Area - Left 2nd intercostal space just lateral to sternum Mitral Area - 5th intercostal space, mid-calvicular line (apex beat) |
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What are the S1 and S2 heart sounds? |
S1 - Closure of Mitral and Tricuspid S2 - Closure of Pulmonic and Aortic |
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Cardiac Output = |
Stroke Volume x HR |
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Describe normal CO
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Resting: 5.5 L/min Avg blood volume is 5.5L Exercise: 25-30L/min in healthy active individuals |
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Describe elements that effect Stroke Volume |
Preload - fluid returning the the heart Contracility - force of contraction/speed/ volume Afterload - resistance ventrice must overcome to move blood --R Pulmonary Vascular Resistance --L Systemic Vascular Resistance |
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Chart on Slide 25 |
Regulation of Cardiac Output |
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Thoracic pressure and venous return during inhalation? |
Thoracic pressure decreases as the diaphragm moves down, creating more space Venous return increases |
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What is Ejection Fraction? |
Percentage of blood that leaves the v entricle compared to total volume that enters Normal is 55-70% HF is 40% or less (systolic heart failure) |
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What are the determinants of Myocardial Oxygen demand |
Factors that affect work on the heart and therefore the amount of O2 the heart needs to perform work HR Systolic BP HR x Syst BP = Rate Pressure Product Wall tension Ventricular volume |
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Blood flow to muscles during exercise |
Blood flow patterns change as a result of aympathetic nervous system action During exercise released of norepinephrine vasoconstricts blood to GI/kidneys and redirects to skeletal muscle |
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Ways to monitor cardiac function? |
Lab/blood work Chest Xray ECG Holter monitor Stress testing MR imaging Cardiac cath Vital Signs |
