epithelial, cardiac muscle, connective tissue

epithelial, smooth muscle, connective tissue

connective tissue, nervous tissue, smooth muscle

epithelial, nervous, connective tissue

because veins are transporting blood from the heart to the rest of the body

because the internal size of veins is so much smaller than arteries

because veins are so much more elastic than arteries

because veins have lower blood pressures than arteries

right ventricle --> left ventricle --> right atrium --> left atrium

right atrium --> right ventricle --> left atrium --> left ventricle

left ventricle --> right atrium --> left atrium --> right ventricle

left atrium --> left ventricle --> right atrium --> right ventricle

it needs to get rid of CO2 and get more oxygen

it doesn't need to - only some blood goes to the lungs, while some other blood goes straight back to the body

it needs to get rid of all the oxygen in it before it goes to the rest of the body

the lungs help to push the blood through the body, so it needs to go there to increase its pressure

it has lymph nodes throughout the body, which filter blood to generate urine/waste

it connects the heart to the lungs, so that gas exchange can occur

it collects fluid from surrounding tissue, filters it, and returns it to the circulatory system

it filters the blood to remove impurities and waste products

it creates blood cells to add to the circulatory system