2.Valves are only in veins so they can stop the blood from moving backwards. Arteries do not need valves because muscles put a lot of pressure on the blood to stop it from moving in the wrong direction
3.two events that occur within the body that aid in venous returns is the respiratory pump and the muscular pump.
4.Walls in arteries are much more thicker because they need to withstand the direct pressure of the pumping heart. And there is not direct pressure on our veins
6.The cerebral arterial circles function is protection. It provides alternative pathways for blood to reach the brain tissues in case of arterial occlusion of impaired bloodflow
7.The anterior and middle cerebral arteries arise from the INTERNAL CAROTID ARTERY.
They serve the CEREBRUM of the brain.
8.Subclavian artery, vertebral artery, basilar artery, posterior cerebral artery.
10.a. radial,brachial, axillary, left subclavian vien, brachiocephalic vein, superior vena cava, right atrium, right ventrice, pulmonary trunk, pulmonary artery, lobar artery, pulmonary cappilaries, pulmonary veins, left atrium, left ventricles, aorta, brachiocephalic artery, subclavian artery, axillary, brachial, radial
b. bicuspid valve,left ventricle of heart,aortic valve,ascending aorta, aortic arch, thoracic aorta, abdominal aorta, right common iliac artery and /or left common iliac artery, right external iliac artery, right femoral artery, right popliteal artery, right anterior tibial artery, right dorsal pedis artery, right arcuate artery, right