[Name of writer appears here] [Course name appears here] [Professor ‘s name appears here] [Date appears here] The Heart The cardiovascular system includes the heart and the blood vessels , and the respiratory system contains those organs which are responsible for carrying oxygen from the air to the blood stream and expelling the waste product of carbon dioxide . Blood is that sticky , red fluid that circulates throughout our bodies in veins and arteries . The heart pumps oxygen into the blood and collects carbon dioxide from it to be expelled through the lungs . The blood vessels lining the air sacs carry the oxygen-containing blood to the left side of the heart from whence it is pumped via the arteries to all parts of the body . When the tissues have used the oxygen to carry out the metabolic processes , carbon dioxide is produced which like oxygen is dissolved in the blood . The carbon dioxide is carried back to the lungs via the veins and the right side of the heart . The cardiovascular and respiratory systems are basic to life and breathing , like the beat of one ‘s heart , is an automatic function which is controlled by the brain (Michael D . Johnson , 2005 ) Blood vessels in body are in the form of arteries , veins and their branches and further divisions . The distribution of the arteries is like a highly branched tree , the common trunk of which , formed by the aorta ,starts at the left ventricle , while the smallest branches termed ,arterioles and the terminal branches , termed capillaries extend to the peripheral parts of the body and different organs . Arteries are found in all parts of the body , except in the hairs , nails , epidermis ,cartilages , and cornea the larger trunks usually occupy the most protected situations , running , in the limbs , along the flexor surfaces ,where they are less exposed to injury (Mary Jones and Geoff Jones ,2004 ) A branch of an artery is smaller than the trunk from which it arises .The arteries , in their distribution , communicate with one another ,forming what are called anastomoses , and these communications are very free between the large as well as between the smaller branches . The anastomosis between trunks of equal size is found where great activity of the circulation is requisite , like brain and in abdomen within gut arteries . In the limbs the anastomoses are most numerous and of largest size around the joints , the branches of an artery above uniting with branches from the vessels below . These anastomoses are of considerable interest to the surgeons (Mary Jones and Geoff Jones , 2004 )The smaller branches of arteries anastomose more frequently than the larger and between the smallest twigs these anastomoses become as numerous as to constitute a close supply network that pervades nearly every tissue of the body . In the fingers , palms , ear lobes of humans and the paws , ears and some other tissues of animals there are short channels that connect arterioles to venules , by passing the capillaries .These arteriovenous anastomose or shunts have thick muscular walls…
