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.
The heart and the coronary arteries. Coronary arteries are blood vessels that provide oxygen-rich blood and other nutrients to the heart muscle. The coronary arteries attach to and wrap around the heart's surface. The left coronary artery branches off into smaller arteries. The most prominent ones are the: Left anterior descending artery, which supplies blood to the front of the heart. Left circumflex artery, which encircles the ..