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Heart Physiology. Cardiac muscle characteristics. Conduction system of the heart. irritability. contractility. self-exciting. rhythmic. Conduction system of the heart. Medulla oblongata of brainstem and autonomic nervous system control heart rate. Control of the heart.
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Cardiac muscle characteristics Conduction system of the heart irritability contractility self-exciting rhythmic
Conduction system of the heart Medulla oblongata of brainstem and autonomic nervous system control heart rate Control of the heart Intrinsic control- SA node- cardiac muscle cells in RA, stimulated by neurons, stimulate other cardiac muscle cells
Conduction system of the heart SA node (in RA)- “pacemaker” of cardiac cycle, sends impulses in atria to stimulate AV node Control of the heart AV node- (in RA) stimulates AV bundle (between ventricles), Purkinje fibers and ventricles
Cardiac Cycle Cardiac cycle= 1 complete heartbeat = .8 sec “Atrial systole with simultaneous ventricular diastole, then atrial diastole with simultaneous ventricular systole” Systole- contraction Diastole- relaxation
Heart sounds- LUBB DUPP Cardiac cycle “LUBB”- AV valves (tricuspid and bicuspid) closing after atrial systole “DUPP”- semilunar valves (pulmonary and aortic) closing after ventricular systole
Diagnostic technique EKG/ECG http://video.about.com/heartdisease/Electrocardiogram.htm
Think back to nerve impulses and polarization, depolarization, repolarization P wave QRS complex T wave
EKG/ECG flatlining
Practical applicationsArtificial pacemaker If SA node is defective, then electronic device is implanted into heart to take SA node’s place
CO= volume of blood pumped by LV per minute ml/min Practical applicationsCardiac output CO= stroke volume (SV) x heart rate (HR) SV= volume of blood pumped from LV per beat ml/beat HR= heart beats per minute b/min
CO= amt of blood in body, because each drop of blood takes 1 minute to circulate through body Cardiac output sample problem Approx. 5 Liters= 5000ml Average fitness CO= SV x HR 5000ml/min = 67 ml/min x 75 b/min
Cardiac output sample problems If a person is a couch potato….. resting CO of 5000ml/min Then 5000 ml/min= 50 ml/min x 100 b/min If they begin to exercise and are now of average fitness…… then resting CO= 5000ml/min = 67 ml/min x 75 b/min
Cardiac output sample problems If they become even more fit or active and resting CO= 5000ml/min = Then 5000ml/min= 83 ml/min x 60 b/min As person becomes more fit- heart becomes more fit at rest, pumps less beats per min., but more blood per beat
Regulation of SV and HR- can be affected by exercise and fitness level Cardiac output Exercise and fitness level- as a person’s fitness level increases, their HR decreases, SV increases, but resting CO can stay the same unless they have more or less blood
Angina pectoris- chest pain, can be symptom of MI Homeostatic imbalances Heart attack (myocardial infarction)- due to blocked coronary artery
Pain areas in red Angina Pectoris treatment
Myocardial infarction anticoagulants
Homeostatic imbalances Murmurs- occurs if valves don’t close correctly or leak Fibrillation- if atria or ventricles don’t contract simultaneously
Ventricular fibrillation Can lead to death because ventricles tremble, but don’t contract, so n0 blood flow
Shocks heart to “reset” it Defibrillator Defibrillator
MVP- bicuspid valve leaks, blood flows backwards Homeostatic imbalances Pericarditis- inflammation of pericardium around heart
Cardiac arrhythmia- irregular heart beat, due to fibrillation or SA node problems Homeostatic imbalances CAD- plaque/cholesterol in coronary arteries
Cardiac arrhythmia Irregular heart beat
Of coronary arteries Coronary artery disease HDL’s- good cholesterol LDL’s- bad cholesterol- clogs arteries
Coronary artery disease Catheterization is a treatment, not a cure, because if one doesn’t change eating habits then it will just happen again
Homeostatic imbalances CHF- heart weakening, not necessarily stoppage
Due to: MI Atherosclerosis Hypertension CAD Other heart diseases CHF-congestive heart failure