Unit 1: The Heart, part A

Fibrous pericardium

outer protective layer

Protects, Anchors the heart, Prevents overfilling

Serous Pericardium

two layers: parietal layer and visceral layer

Visceral layer of serous pericardium

epicardium

parietal layer

lines the inside of the fibrous pericardium.

visceral layer

sits directly on the external surface of the heart.

The Pericardial Cavity

Between the parietal and visceral layers.

contains fluid to decrease friction.

myocardium

'“the muscular layer of the heart.” contains spiral bundles of cardiac muscle cells.

myocardium also contains/supports

fibrous skeleton of the heart

The fibrous skeleton of the heart

• anchors cardiac muscle fibers

• supports the great vessels and valves

• limits the spread of action potentials to specific paths

endocardium

is continuous with the endothelial lining of blood vessels.

right side of the heart

handles the pulmonary circuit.

That's the circuit between:

Heart → lungs → heart

Its job is to send blood to the lungs.

left side of the heart

handles the systemic circuit.

That's:

Heart → body → heart

Its job is to send blood to the body's tissues.

Coronary sulcus (atrioventricular groove)

encircles the junction of the atria and ventricles

Auricles

increase atrial volume

right atrium receives blood from

1. Superior vena cava

2. Inferior vena cava

3. Coronary sinus

The left atrium receives blood from

Right and left pulmonary veins.

Blood leaves the right ventricle through the:

Pulmonary trunk, which ultimately carries blood toward the lungs.

Blood leaves the left ventricle through the:

Aorta, which carries blood toward the systemic circulation.

walls of the atria are ridged by

pectinate muscles

walls of the ventricles are ridged by

trabeculae carnae

Papillary muscles project into the

ventricular cavities

Equal volumes of blood are pumped

to the pulmonary and systemic circuits

Pulmonary circuit

a short, low-pressure circulation

Systemic circuit

blood encounters much resistance in the long pathways

Coronary Circulation Arteries

Right and left coronary (in atrioventricular

groove), marginal, circumflex, and anterior

interventricular arteries

Coronary Circulation Veins

Small cardiac, anterior cardiac, and great

cardiac veins

Angina pectoris

Thoracic pain caused by a fleeting deficiency in blood delivery to the myocardium

Cells are weakened

Myocardial infarction (heart attack)

Prolonged coronary blockage

Areas of cell death are repaired with noncontractile scar tissue

Atrioventricular (AV) valves

Prevent backflow into the atria when ventricles

contract

Chordae tendineae

anchor AV valve cusps to papillary muscles

Semilunar (SL) valves

Prevent backflow into the ventricles when ventricles relax