The cardiovascular system is a part of the larger circulatory system, which circulates fluids all through the physique. The circulatory system consists of both the cardiovascular system and the lymphatic system. The cardiovascular system moves blood all through the physique, and the lymphatic system moves lymph, which is a clear fluid that’s just like the plasma in blood.
Blood comprises vitamins from the meals you eat and oxygen from the air you breathe. It additionally accommodates hormones and cells that struggle an infection. The blood additionally transports waste merchandise to varied locations that then promptly take away the waste from the physique.
The parts of the cardiovascular system include the heart, which is the organ that pumps the blood, and a network of blood vessels:
Arteries: The blood vessels that take blood away from the heart
Veins: Blood vessels that return blood to the heart
Capillaries: Very small vessels that lie between the arteries and veins
The portal vein and its tributaries carry blood from parts of the digestive system to the liver before reaching the heart.
The heart is a muscular pump with four chambers inside: the right and left atria and the right and left ventricles. Those four chambers allow the heart to pump blood through the following two circulatory pathways:
Systemic circulation: Takes oxygen-rich blood to the tissues and organs of the body
Pulmonary circulation: Takes oxygen-depleted blood to the lungs and oxygen-rich blood back to the heart again
Here’s the pathway taken by the blood while it’s in systemic circulation, delivering oxygen-rich blood throughout the body:
The left ventricle of the heart receives oxygenated blood from the left atrium.Blood is ejected from the left ventricle into the aorta, a large artery.The ascending aorta sends blood to the upper thorax, upper extremities, neck, and head.The descending aorta sends blood to the lower thorax, the abdomen, the pelvis, and the lower extremities.The blood leaves the ascending and descending parts of the aorta and enters a network of systemic arteries that run to all places of the body.Blood passes from the smallest arteries (called arterioles) into the capillary beds. In the capillary beds, blood exchanges oxygen, nutrients, and waste products with the tissues.The oxygen-poor blood leaves the capillary beds via small veins (called venules) and drains into a network of systemic veins that eventually lead to the venae cavae (either of the two large veins leading into the heart).The superior vena cava receives blood from the upper thorax, head, neck, and upper extremities.The inferior vena cava receives blood from the lower thorax, the abdomen, the pelvis, and the lower extremities.The venae cavae empty the oxygen-poor blood into the right atrium of the heart.
After systemic circulation, the blood in the right atrium is depleted of oxygen, so it needs to go to the lungs to exchange carbon dioxide for oxygen. The pathway from the heart to the lungs and back to the heart is called pulmonary circulation, and it takes the following path:
The right ventricle receives the oxygen-depleted blood from the right atrium.The blood leaves the right ventricle and enters the pulmonary trunk, which splits into two pulmonary arteries.The pulmonary arteries lead to the lungs, where exchange of gases takes place. Carbon dioxide is removed from the blood, and oxygen enters the blood.Blood leaves the lungs via the pulmonary veins.The pulmonary veins carry freshly oxygenated blood to the heart while the systemic veins carry oxygen-poor blood to the heart.The oxygenated blood enters the left atrium of the heart.The blood in the left atrium moves into the left ventricle and enters the systemic circulation.
Heart attacks (myocardial infarcts) occur when blood flow to some part of the heart is blocked, causing damage to part of the heart. Arrhythmia is a problem with the heart rhythm; the heart may beat too slow, too fast, or irregularly.
Cardiovascular disease can affect the brain as well. Ischemic strokes happen when a blood vessel in the brain is blocked. Hemorrhagic strokes occur when a blood vessel in the brain breaks open. Either type of stroke can result in damage to a part of the brain.
