Species range in size from the hefty Common Raven (Corvus corax), at 1.5 kg (3 lb 5 oz) and 70 cm (2 ft 3 in), to the diminutive Short-tailed Pygmy Tyrant (Myiornis ecaudatus), at just 4.2 g (0.14 oz) and 6.5 cm (2 Â½ in).
The heart receives its own supply of blood from the coronary arteries. Two major coronary arteries branch off from the aorta near the point where the aorta and the left ventricle meet. These arteries and their branches supply all parts of the heart muscle with blood.hen the coronary arteries narrow to the point that blood flow to the heart muscle is limited (coronary artery disease), collateral vessels may enlarge and become active.
Arteries and veins carry blood around your body. Arteries take blood away from your heart, delivering it to your organs and muscles. Veins bring blood back to your heart from those same organs and muscles. Your main arteries include the coronary arteries of your heart, the carotid and cerebral arteries of your brain, and the peripheral arteries, which stretch out into your limbs.