cardiovascular system heart. location – mediastinum pericardial sac pericardial cavity pericardial...
TRANSCRIPT
Cardiovascular System
Heart
Heart
• Location – Mediastinum
• Pericardial Sac
• Pericardial Cavity
• Pericardial Fluid
• Parietal Pericardium
Heart Wall
• Epicardium = Visceral Pericardium
• Myocardium– Trabeculae carneae
• Endocardium
Heart Chambers
• Atria (Atrium)
• Auricles
• Interatrial septum
Heart Chambers
• Ventricles
• Interventricular septum
• Coronary sulcus
Valves
• Atrioventricular (Tricuspid & Bicuspid)– Chordae tendineae– Papillary muscles
• Semilunar– Pulmonary– Aortic
Vessels
• Superior Vena Cava
• Inferior Vena Cava
• Pulmonary Trunk (Arteries)
• Pulmonary Veins
• Aorta
Coronary Circulation
• Aorta
• Coronary arteries
• Myocardium
• Cardiac veins
• Coronary sinus
• Right atrium
Cardiac Muscle physiology
• Myocardium
• Automated excitement
• No graded responses
• No tetany
• No anaerobic metabolism
Cardiac Muscle
• Striated, Involuntary
• Intercalated discs
• Refractory period prevents tetany
• Energy– ATP – aerobic metabolism– Coronary circulation providing O2
Excitation of cardiac muscle
• Depolarization to threshold is spontaneous due to decreased outflow of K+
• Sinoatrial node (SA)– Depolarizes every .8 sec. At rest– Depolarizes due to change in permeability– Pacemaker
Conduction
• Spread to both atria
• AV node (.1 sec. Delay)
• AV Bundle (Bundle of His)
• Purkinje = Conduction fibers
• Myocardial cells of ventricle
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Cardiac Cycle
• Systole
• RV = 30 mm Hg
• LV = 120 mm Hg
Cardiac Cycle
• Diastole
Time for cardiac cycle
• Entire cycle is .8 sec.
• Atrial systole .1 sec
• Atrial diastole .7 sec
• Ventricular systole .3 sec
• Ventricular diastole .5 sec
Pressure Curves
• Atrium
• Ventricle
• Aortic
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Heart Sounds
• S1 = AV valves closing
• S2 = Semilunar valves closing
CARDIAC OUTPUT
• CO = HR x SV
• 5-6 liters/minute
• 70 beats/minute x 80 mls/beat
Cardiac Reserve
• Difference between maximum CO and resting CO
• Can increase 700%!!
Heart Rate Control
• Sympathetic Stimulation
• Parasympathetic Stimulation
Stroke Volume Control
• SV = End-diastolic volume – End-systolic volume
• End-diastolic volume– Length of diastole– Venous Return
Stroke Volume Control
• End-systolic volume– Frank-Starling Law– Sympathetic Nervous System– Parasympathetic Nervous System
Factors influencing Cardiac Function
• Cardiac Center in Brainstem
• Exercise,Temperature
• Ions (K, Ca, Na)
• Sex
• Age
Electrocardiogram
• EKG, ECG
• Leads
• P wave – atrial depolarization
• QRS complex – ventricular depolarization
• T wave - ventricular repolarization