Download 8/31 Lecture 5

Blood and Heart
Heart Position
Heart Layers
Chambers of the Heart
Heart Valves
The Two Circulations
Movie
Marieb 18
Serous Pericardium
Cardiac Muscles are Arranged in Bundles
Fibrous Skeleton of
the Heart
Elastin and Collagen
Support/Anchor
Atria and Ventricles
Valves and Blood Flow
Papillary Muscles Pull on “Safety Lines”
Chordae tendineae
Papillary muscle
contracts before
ventricles
The Two Circulations
Pulmonary
Systemic
The Two Circulations
Pulmonary- low
volume, low
resistance, low
pressure
Systemic- high
volume, high
resistance, high
pressure
The Cardiac Cycle
Wiggers Diagram
Cardiac Muscle drives the Cardiac Cycle
Pacemaker
Conducting
Contracting
Automaticity/Pacemaker Function of Heart
Pacemaker Cells of the Heart
Modified
myocardium
Intrinsic Firing
Pattern
Set heart rate
Normal Heart Contractions and the SA Node
Sinoatrial Node
Intrinsic 100bpm
Vagal Tone
Internodal Pathway
AV Node
Atrioventricular node
Intrinsic 50bpm
Conduction very slow
(Atria contract)
Bundle of His/Atrioventricular Bundles
Surrounded by
fibrous skeleton
Quick
Splits R/L Branch
Purkinje Fibers
Very Fast
Activate cardiac
bundles in a fixed
pattern
Sinus Rhythm
1) SA sets the pace
1) 60-100bpm
1) Proper conduction
pattern
Timing in the Heart
Conduction Velocities
Atria 1m/sec
AV node 0.01-0.05 m/sec
His/Purkinje 2-4 m/sec