I.                Chapter 21:  The Heart

A.               General organization

1.                Pulmonary and Systemic circuits (Fig 21.1)

B.               Location (Fig 21.2a, 21.2b, 21.2c, 21.2d)

1.                Lies in mediastinum

2.                Apex points anteriorly and left

3.                Trapezoidal shape

C.               Structure of the Heart

1.                Coverings (Fig 21.2b, 21.3ab, 21.3de)

a)                Pericardium

(1)             Fibrous pericardium

(2)             Parietal layer of serous pericardium

(3)             Visceral layer of serous pericardium

2.                The Heart Wall (Fig 21.3b)

a)                Epicardium (visceral serous pericardium)

b)               Myocardium (cardiac muscle)

(1)             Intercalated discs

(2)             Gap junctions & desmosomes

c)                Endocardium (endothelium on CT & small amt of areolar CT)

D.              Fibrous Skeleton (Fig 21.7a)

1.                Functions

a)                Anchor valves

b)               Prevention of dilatation of valve openings

c)                Directs spread of excitation through heart

E.               Superficial Anatomy of Heart (Fig 21.4, 21.5a, 21.5b)

1.                Borders

2.                Sulci: coronary sulcus, anterior & post. interventricular sulci.

F.               Heart Chambers (Fig 21.6a, 21.6cd)

1.                Right atrium

a)                Vena cavae

b)               Coronary sinus

c)                External auricle

d)               Pectinate muscles

e)                Fossa ovalis (closure of formen ovale)

2.                Right ventricle

a)                Pulmonary trunk

b)               Trabeculae carneae

c)                Papillary muscles

3.                Left atrium

a)                Pulmonary veins

b)               External left auricle

4.                Left ventricle

a)                Pumps into aorta

b)               Trabeculae carneae

c)                Papillary muscles

5.                Differences in ventricular walls (Fig 21.6)

G.              Heart Valves (Fig 21.7a, 21.7b)

1.                Structure

a)                Atrioventricular valves (Fig 21.6a, 21.7)

(1)             Right (tricuspid)

(2)             Left (bicuspid [mitral])

b)               Semilunars – three half-moon shaped cusps (Fig 21.7)

(1)             Aortic

(2)             Pulmonary

2.                Function – prevent backflow of blood (Fig 21.7)

a)                Chordae tendinae and papillary muscles prevent prolapse (backflow through everted valves)

H.              Auscultation: Heart sounds (Fig 21.8)

1.                Normal – “Lub – Dup”

2.                Abnormal - Murmurs

a)                Incompetent valves

b)               Stenotic valves

I.                 Coronary Vasculature (Fig 21.9a, 21.9b)

1.                Arteries

a)                Left Coronary a.

b)               Anterior Interventricular a.

c)                Circumflex a.

d)               Right Coronary a.

e)                Marginal a.

f)                Posterior Inverventricular a.

2.                Veins

a)                Coronary Sinus

b)               Great Cardiac v.

c)                Middle Cardiac v.

d)               Small Cardiac v.

J.                Conducting System (Fig 21.12)

1.                Sinoatrial node

2.                Atrioventricular node

3.                Atrioventricular bundle (bundle of His)

4.                Right and left bundle branches

5.                Purkinje fibers

K.              Autonomic Innervation (Fig 21.14)

1.                Sympathetic (C₆-T₄) and Parasympathetic (Vagus, CN X) innervation