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Med Surg exam #2
Question | Answer |
---|---|
Blood flow pattern: | R atria receives blood from periphery via the inferior & superior vena cava Blood flows into RV then to the PA and the lungs for O2 O2 blood flows back to the left side of the heart via the PV O2 blood flows thru the LA and LV and outbody via the aor |
Left & right coronary arteries | provide oxygenated blood to the myocardium |
Atrioventricular valves: | (separate the atria and the ventricles) tricuspid right mitral left |
Semilunar valves: | pulmonic between RV and PA aortic between LV and aorta |
Depolarization myocardial contraction | Sodium ions enter cells altering permeability of cell membrane to calcium Calcium enters cells and is released from intracellular stores |
Repolarization | cells returning to resting state myocardial relaxation K comes back in |
Stroke volume | amount of blood ejected from the ventricle per heartbeat |
Cardiac output | the amount of blood ejected per minute |
Factors affecting heart rate | activity, SA node function, adrenal & thyroid function, baroreceptors in aortic arch & carotids that respond to hyper/hypotensive events |
Factors affecting stroke volume | preload, afterload, diureses, vasodilators, contractility, ejection fraction (pushed out from the heart) |
Preload | Degree of stretch in cardiac muscle at end of diastole |
Afterload | Degree of resistance the heart is pumping against Systemic vascular resistance (SVR)- pressure left ventricle contracts against Pulmonary vascular resistance (PVR)- pressure the right ventricle contracts against |
Contractility | force generated by the myocardium Decreased by hypoxemia, acidosis, beta adrenergic blocking agents Tenormin (atenolol), Lopressor (metoprolol) Enhanced by circulating catecholamines, sympathetic stimulation, medications Digoxin, dopamine, dobutamine |
S/S of Cardiac problems | Chest pain or pressure Shortness of breath (not enough 02, fluid in lungs) Edema and weight gain (HF) Palpitations(abnormal heart rythm),(racing, butterflies) Fatigue (heart pumps harder tires more easy) Dizziness or Syncope |
Physical Assessment | Skin Blood pressure (perfusion) Pulses Heart inspection, palpation, percussion, and auscultation Inspection of extremities(edema, perfusion, ulcers,) Lung assessment Abdominal assessment |
Closure of the mitral and tricuspid valves creates | the first heart sound (S1) |
Closing of the aortic and pulmonic valves produces | the second heart sound (S2 |
Cardiac enzymes | CK elevation indicates muscle involvement LDH rises & peaks later than CK |
CK-MB specific for MI | Relative Index (RI)= percentage of CK-MB per CK |
Myoglobin (cardiac marker) | Small molecular weight protein Released from damaged cardiac muscle Rises within 1-3 hours after MI Elevation may occur with other muscle damage |
Troponin I & T: proteins found only in cardiac muscle (cardiac marker) | Highly specific for myocardial injury |
Diagnostic tests | Chest x-ray and fluoroscopy (shows HF, enlarged) Electrocardiography |
Diagnostic tests con't | Cardiac stress testing (chemical, meds, treadmill) (NPO4Hr, no caffeine, B-blockers) Echocardiography(chambers, valves) Radionuclide Imaging Cardiac Catheterization Angiography Electrophysiologic testing |