how many arteries we have?
481049
There are 2 main arteries that supply the heart:\n\n1. Right coronary artery\nBranches:\na. Marginal \nb. Posterior interventricular\nc. Some small branches (nodal, infundibular, terminal)\n\n2. Left coronary artery\nBranches:\na. Anterior interventricular\nb. Some small branches (left atrial, pulmonary, terminal)\n\nOthers are collateral circulations.
604046
1.Closed circulatory system with 5 aortic arches \n2.Complete specialized digestive tract\n3.Regeneration of lost parts
309458
One?  There are at least two - birth and death.  If you mean the one most important, it's the one in between, the living part.
44789
cardiac, smooth, and skeletal.
249298
All arteries carry oxygenated blood and all veins carry unoxygenated blood except for in the pulmonary circuit, where the pulmonary arteries carry unoxygenated blood from the heart to the lungs, and the pulmonary veins carry oxygenated blood from the lungs back to the heart.
682856
Common animal (including human) organs include the heart, lungs, brain, eye, stomach, spleen, pancreas, kidneys, liver, intestines, skin, uterus, and bladder.\n\nBlood vessels exist in varying calibers:\n\nArteries \nAorta (the largest artery, carries blood out of the heart) \nBranches of the aorta, such as the carotid artery, the subclavian artery, the celiac trunk, the mesenteric arteries, the renal artery and the ileac artery. \nArterioles \nCapillaries (the smallest blood vessels) \nVenules \nVeins \nLarge collecting vessels, such as the subclavian vein, the jugular vein, the renal vein and the iliac vein. \nVenae cavae (the 2 largest veins, carry blood into the heart)
273358
It has approximately 6 quarts (or 5.6 liters) of blood.3\n\nsome quick facts for you to chew on.\n\nIn one day, your blood travels nearly 12,000 miles. \nYour heart beats around 35 million times per year. \nYour heart pumps a million barrels of blood during the average lifetime -- enough to fill three supertankers.
136322
The cardiovascular system is a closed system, meaning that blood remains inside the vessels no matter how small they are.  The process of diffusion drives oxygen, carbon dioxide, wastes and nutrients between the tissues and the blood inside the blood vessels-blood just goes around the body.  Humans have a 4-chambered heart: 2 ventricles and 2 atria (sing: atrium).  The atria receive blood and the ventricles "expel" the blood (pumps the blood away from the heart).  You can partition the heart into two sides (left and right), each with its own ventricle and atrium.   One side is for the systemic circulation (to the body) and the other is for the pulmonary circulation (to the lungs).  Blood (deoxygenated) from the body collects in the right atrium, which passes the blood to the right ventricle, which relays the blood to the pulmonary arteries (arteries to the lungs) to get oxygen and expel carbon dioxide.  Once the blood in the lungs acquires oxygen, it passes to the pulmonary veins and into the left atrium.  Then, the blood goes into the left ventricle and is pumped into the aorta (think of it as the largest artery in the body or like in the water supply, the main tube of water where all of the other tubes originate). From the aorta it goes to the arteries and then to the arterioles and the capillary networks (where gas exchange occurs).  After being depleted of oxygen, it goes to the venules to the veins then to the vena cavae and back into the right atrium and it goes around again. :-)
846065
Vasculature is regulated by your autonomic nervous system if that is what you mean.  Theres a lot more to the parsympathetic, sympathetic stuff and it would take awhile to explain without you asking about a specific part of it.
800384
I believe your answers are right, except that 6 is false.  The pulmonary artery carries deoxygenated blood away from the heart to the lungs.  It is the only artery, which carry blood away from the heart, that contains deoxy blood.
1021658
no they dont ..  the septum devides the heart into two major parts
678231
I think you are asking if it is possible to know how many damaged veins in the heart without exploratory surgery.  Yes, except it would be about the coronary (heart) arteries, not veins.  The arteries are the size of fairly large veins, in fact, leg veins are used when bypass surgery is done to the coronary arteries.  To find out how many and how badly the arteries are damaged by calcium and plaque (cholesterol) build-up, an Angiogram can be done, consisting of a tiny camera at the end of very thin fine tubing inserted into an artery at the groin, and slowly moved up and into the heart arteries.  An Angiogram would be done only in the event of heart disease symptoms, because the procedure itself carries some risk.
80241
There are two major arteries in the leg....the Femoral which extends from above the knee through the top of the thigh and the Tibial which extends from the femoral through the lower leg....and there are three major veins in the leg and foot...the Tibial which runs from the feet to the thigh..the Saphenous and Femoral which both run from knee to pelivs through the thigh.
530920
we have four limbs, being two hands and two legs. That's just how we evolved.
285600
Hmmm, good question.  I guess I automatically assumed capillaries, but they might not be small enough to be considered capillaries.  On second thought, I'd go with arterioles because these vessels have oxygenated blood in them (meaning they came from the heart), are too small to be arteries but not small enough to be capillaries, and are obviously not viens.
144833
They are the ribs.  Though technically only 7 of them go completely around to surround the heart and lungs.
1156327
How many gears do you have?