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Copyright © 2009 Pearson Education, Inc.
Figure 8.6a The heart.
Blood Pathway Through the Heart & Lungs
Figure 17.5
Copyright © 2009 Pearson Education, Inc.
Figure 8.7 A view of the heart showing major blood vessels, chambers, and valves.
Superior vena cava
Pulmonarysemilunar valveRight atrium
Right AV valveRight ventricle
Inferior vena cava
Pulmonary trunk
Left pulmonary veins
Left atrium
Left AV valve
Aortic semilunar valve
Chordae tendineae
Papillary muscles
Left ventricle
Septum
Right pulmonary artery
Left pulmonary artery
Aorta
External Heart: Posterior View
Figure 17.4d
•The auricle is a part of each atrium. A small, cone-shaped, muscular pouch that projects from each atrium, located at the receiving end of the atria. Visually, they look like wrinkled pouch-like structures.
•Auricles help their respective atria hold more blood. •They are called auricles because they were thought to resemble dog's ears.
•In older references, “auricle” was used to describe the entire atrium.
Alternate names for AV valves
Right
Tricuspid
Left
Bicuspid
Mitral
Heart Valves
Figure 17.8a, b
Semilunar Valve Function
Figure 17.10
Atrioventricular Valve Function
Figure 17.9
Copyright © 2009 Pearson Education, Inc.
Figure 8.12 Heart valves.
Heart Valves
Figure 17.8c, d
Copyright © 2009 Pearson Education, Inc.
Figure 8.10 Blood vessels of the heart.
Copyright © 2009 Pearson Education, Inc.
Figure 8.18 A coronary angiogram.
Copyright © 2009 Pearson Education, Inc.
Figure 8.19 Coronary artery bypass grafts.
Sequence of Excitation
Figure 17.14a
Heart Physiology: Sequence of Excitation
• Sinoatrial (SA) node in right atrium generates impulses about 75 times/minute; dominant autorythmic cells; nervous system may regulate
• Atrioventricular (AV) node delays the impulse approximately 0.1 second
• Impulse passes from atria to ventricles via the atrioventricular bundle (AV bundle)
• AV bundle splits into two bundle branches in the interventricular septum
• Bundle branches carry the impulse toward the apex of the heart
• Purkinje fibers carry the impulse from the heart apex to the ventricular walls
Cardiac Cycle
• Cardiac cycle refers to all events associated with blood flow through the heart; electrical events, valve activity, heart sounds, chamber contractions and changes in blood pressure– Systole – contraction of heart muscle– Diastole – relaxation of heart muscle
Heart Sounds
• Heart sounds (lub-dup) are associated with closing of heart valves– First sound occurs as AV valves close and
signifies beginning of systole– Second sound occurs when SL valves close
at the beginning of ventricular diastole
• Heart murmurs-obstruction in the flow of blood, valve irregularity
Cardiac Conditioning
• Exercise will increase cardiac muscle mass
• Increased cardiac muscle mass increases the strength of contraction
• Heart beats less and rests more