EVERYDAY SCIENCE

Detailed explanation-1: -Arteries carry blood away from the heart and veins carry blood back to the heart.

Detailed explanation-2: -The great vessels of the heart include your aorta, pulmonary trunk, pulmonary veins and vena cava (superior and inferior). They connect directly to your heart and play a vital role in your circulatory system.

Detailed explanation-3: -There are five classes of blood vessels: arteries and arterioles (the arterial system), veins and venules (the venous system), and capillaries (the smallest bloods vessels, linking arterioles and venules through networks within organs and tissues) (Fig 1).

Detailed explanation-4: -Blood comes into the right atrium from the body, moves into the right ventricle and is pushed into the pulmonary arteries in the lungs. After picking up oxygen, the blood travels back to the heart through the pulmonary veins into the left atrium, to the left ventricle and out to the body’s tissues through the aorta.

Detailed explanation-5: -Blood flows in the same direction as the decreasing pressure gradient: arteries to capillaries to veins. The rate, or velocity, of blood flow varies inversely with the total cross-sectional area of the blood vessels. As the total cross-sectional area of the vessels increases, the velocity of flow decreases.