Nourishing the Heart:
The heart is nourished by the coronary circulation which supplies blood and nutrients to the
heart. Just by looking at the heart we cannot see the bulk of the coronary system. Most of
coronary system is deep. Each person has a different coronary system unique to their body. The
blood within the heart does not supply oxygen and other nutrients to the cells of the heart.
Cardiac Myocytes - 40% is made of mitochondria - enables large production of ATP
50% is made of the filaments
Heart - abundance of myoglobin stores limited amounts of O2 within the
Ostia - Large opening, whole
Coronary Sinus - Larger opening (example: nasal sinus)
Coronary circulation: Coronary Ostia - Coronary arteries - Cardiac Veins - Coronary sinus -
Major Coronary Arteries: Both transverse the epicardium and branch several times
• Right Coronary Artery
• Left Coronary Artery
A person is either 70% right dominant, 10% left dominant, or 20% Co-dominant.
Other Arteries and Veins:
Left main Coronary
• Circumflex - Travels in coronary sulcus to left atrium and the lateral wall of left ventricle
• Left anterior descending - Vary in size. Delivers to left and right ventricles, and septum;
It travels down the anterior surface of the septum to the apex of the heart.
• The Conus - upper right ventricle
• The Right Marginal Branch - down right side to Apex of heart
• Posterior Descending Branch - Along coronary sulcus provides blood to posterior side of
left and right ventricle.
Collateral arteries: bi-directional
• Protection function
• native system for coronary by-pass
• Support flow in either direction
• collateral growth from decreased ischemia which increases sheer stress...collateral
Coronary arteries not open under resting or normal healthy conditions. The increase in pressure
allows the coronary arteries to open and the blood flow follows. Coronary Capillaries: 3300 capillaries per square mm - one capillary per muscle cell.
Cardiac Muscles: Alterations dramatically affect blood flow in the capillaries. Ventricular
hypertrophy, stenotic or regurgitant, the capillary network does not expand along with muscle
fiber size. The same number of capillaries must now perfuse a larger area. But this cannot
happen for a long period of time.
Coronary Veins: Travels alongside the arteries.
• Coronary sinus
• Heart receives most of blood flow during diastole
• Systole, the