Figure 8.6a The heart.

Blood Pathway Through the Heart & Lungs Figure 17.5

Right pulmonary artery Pulmonary trunk Figure 8.7 A view of the heart showing major blood vessels, chambers, and valves. Aorta Superior vena cava Left pulmonary artery Right pulmonary artery Pulmonary trunk Left pulmonary veins Left atrium Pulmonary semilunar valve Aortic semilunar valve Left AV valve Right atrium Left ventricle Right AV valve Chordae tendineae Right ventricle Papillary muscles Septum Inferior vena cava

External Heart: Posterior View Figure 17.4d

The auricle is a part of each atrium 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

Figure 8.12 Heart valves.

Heart Valves Figure 17.8c, d

Figure 8.10 Blood vessels of the heart.

Figure 8.18 A coronary angiogram.

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