Transcript Cardiovascular System

Cardiovascular System
Heart
Heart
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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
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Superior Vena Cava
Inferior Vena Cava
Pulmonary Trunk (Arteries)
Pulmonary Veins
Aorta
Coronary Circulation
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Aorta
Coronary arteries
Myocardium
Cardiac veins
Coronary sinus
Right atrium
Cardiac Muscle physiology
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Myocardium
Automated excitement
No graded responses
No tetany
No anaerobic metabolism
Cardiac Muscle
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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
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Spread to both atria
AV node (.1 sec. Delay)
AV Bundle (Bundle of His)
Purkinje = Conduction fibers
Myocardial cells of ventricle
Cardiac Cycle
• Systole
• RV = 30 mm Hg
• LV = 120 mm Hg
Cardiac Cycle
• Diastole
Time for cardiac cycle
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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
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
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Cardiac Center in Brainstem
Exercise,Temperature
Ions (K, Ca, Na)
Sex
Age
Electrocardiogram
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EKG, ECG
Leads
P wave – atrial depolarization
QRS complex – ventricular depolarization
T wave - ventricular repolarization