File Name: circulatory system parts and function .zip
Organs of the Circulation
The circulatory system , also called the cardiovascular system or the vascular system , is an organ system that permits blood to circulate and transport nutrients such as amino acids and electrolytes , oxygen , carbon dioxide , hormones , and blood cells to and from the cells in the body to provide nourishment and help in fighting diseases , stabilize temperature and pH , and maintain homeostasis.
The circulatory system includes the lymphatic system , which circulates lymph. Lymph is essentially recycled excess blood plasma after it has been filtered from the interstitial fluid between cells and returned to the lymphatic system. The cardiovascular from Latin words meaning "heart" and "vessel" system comprises the blood, heart, and blood vessels. The circulatory system of the blood is seen as having two components, a systemic circulation and a pulmonary circulation.
While humans, as well as other vertebrates , have a closed cardiovascular system meaning that the blood never leaves the network of arteries , veins and capillaries , some invertebrate groups have an open cardiovascular system.
The lymphatic system, on the other hand, is an open system providing an accessory route for excess interstitial fluid to be returned to the blood. Many diseases affect the circulatory system. This includes cardiovascular disease , affecting the cardiovascular system, and lymphatic disease affecting the lymphatic system.
Cardiologists are medical professionals which specialise in the heart, and cardiothoracic surgeons specialise in operating on the heart and its surrounding areas. Vascular surgeons focus on other parts of the circulatory system. The essential components of the human cardiovascular system are the heart , blood and blood vessels.
The systemic circulation can also be seen to function in two parts — a macrocirculation and a microcirculation. An average adult contains five to six quarts roughly 4.
Also, the digestive system works with the circulatory system to provide the nutrients the system needs to keep the heart pumping. The cardiovascular systems of humans are closed, meaning that the blood never leaves the network of blood vessels.
In contrast, oxygen and nutrients diffuse across the blood vessel layers and enter interstitial fluid , which carries oxygen and nutrients to the target cells, and carbon dioxide and wastes in the opposite direction. The other component of the circulatory system, the lymphatic system , is open.
Oxygenated blood enters the systemic circulation when leaving the left ventricle , through the aortic semilunar valve.
The first part of the systemic circulation is the aorta , a massive and thick-walled artery. The aorta arches and gives branches supplying the upper part of the body after passing through the aortic opening of the diaphragm at the level of thoracic ten vertebra, it enters the abdomen. Later it descends down and supplies branches to abdomen, pelvis, perineum and the lower limbs.
The walls of aorta are elastic. This elasticity helps to maintain the blood pressure throughout the body. When the aorta receives almost five litres of blood from the heart, it recoils and is responsible for pulsating blood pressure.
Moreover, as aorta branches into smaller arteries, their elasticity goes on decreasing and their compliance goes on increasing. Arteries branch into small passages called arterioles and then into the capillaries. Capillaries merge into venules , which merge into veins.
The venous system feeds into the two major veins: the superior vena cava — which mainly drains tissues above the heart — and the inferior vena cava — which mainly drains tissues below the heart. These two large veins empty into the right atrium of the heart. The general rule is that arteries from the heart branch out into capillaries, which collect into veins leading back to the heart.
Portal veins are a slight exception to this. In humans the only significant example is the hepatic portal vein which combines from capillaries around the gastrointestinal tract where the blood absorbs the various products of digestion; rather than leading directly back to the heart, the hepatic portal vein branches into a second capillary system in the liver.
The heart pumps oxygenated blood to the body and deoxygenated blood to the lungs. In the human heart there is one atrium and one ventricle for each circulation, and with both a systemic and a pulmonary circulation there are four chambers in total: left atrium , left ventricle , right atrium and right ventricle. The right atrium is the upper chamber of the right side of the heart. The blood that is returned to the right atrium is deoxygenated poor in oxygen and passed into the right ventricle to be pumped through the pulmonary artery to the lungs for re-oxygenation and removal of carbon dioxide.
The left atrium receives newly oxygenated blood from the lungs as well as the pulmonary vein which is passed into the strong left ventricle to be pumped through the aorta to the different organs of the body. The heart itself is supplied with oxygen and nutrients through a small "loop" of the systemic circulation and derives very little from the blood contained within the four chambers. The coronary circulation system provides a blood supply to the heart muscle itself.
The coronary circulation begins near the origin of the aorta by two coronary arteries : the right coronary artery and the left coronary artery. After nourishing the heart muscle, blood returns through the coronary veins into the coronary sinus and from this one into the right atrium.
Back flow of blood through its opening during atrial systole is prevented by Thebesian valve. The smallest cardiac veins drain directly into the heart chambers. The circulatory system of the lungs is the portion of the cardiovascular system in which oxygen -depleted blood is pumped away from the heart, via the pulmonary artery , to the lungs and returned, oxygenated, to the heart via the pulmonary vein.
Oxygen deprived blood from the superior and inferior vena cava enters the right atrium of the heart and flows through the tricuspid valve right atrioventricular valve into the right ventricle, from which it is then pumped through the pulmonary semilunar valve into the pulmonary artery to the lungs.
Gas exchange occurs in the lungs, whereby CO 2 is released from the blood, and oxygen is absorbed. The pulmonary vein returns the now oxygen-rich blood to the left atrium.
A separate system known as the bronchial circulation supplies blood to the tissue of the larger airways of the lung. Systemic circulation is the portion of the cardiovascular system which transports oxygenated blood away from the heart through the aorta from the left ventricle where the blood has been previously deposited from pulmonary circulation, to the rest of the body, and returns oxygen-depleted blood back to the heart.
The brain has a dual blood supply that comes from arteries at its front and back. These are called the "anterior" and "posterior" circulation respectively.
The anterior circulation arises from the internal carotid arteries and supplies the front of the brain. The posterior circulation arises from the vertebral arteries , and supplies the back of the brain and brainstem. The circulation from the front and the back join together anastomise at the Circle of Willis. It branches from the abdominal aorta and returns blood to the ascending vena cava. It is the blood supply to the kidneys , and contains many specialized blood vessels.
The lymphatic system is part of the circulatory system in many complex animals such as mammals and birds. It is a network of lymphatic vessels and lymph capillaries , lymph nodes and organs , and lymphatic tissues and circulating lymph.
One of its major functions is to carry the lymph, draining and returning interstitial fluid back towards the heart for return to the cardiovascular system, by emptying into the lymphatic ducts. Its other main function is in the adaptive immune system. The development of the circulatory system starts with vasculogenesis in the embryo.
The human arterial and venous systems develop from different areas in the embryo. The arterial system develops mainly from the aortic arches , six pairs of arches which develop on the upper part of the embryo. Fetal circulation begins within the 8th week of development.
Fetal circulation does not include the lungs, which are bypassed via the truncus arteriosus. Before birth the fetus obtains oxygen and nutrients from the mother through the placenta and the umbilical cord. The human arterial system originates from the aortic arches and from the dorsal aortae starting from week 4 of embryonic life. The first and second aortic arches regress and forms only the maxillary arteries and stapedial arteries respectively.
The arterial system itself arises from aortic arches 3, 4 and 6 aortic arch 5 completely regresses. The dorsal aortae, present on the dorsal side of the embryo, are initially present on both sides of the embryo. They later fuse to form the basis for the aorta itself.
Approximately thirty smaller arteries branch from this at the back and sides. These branches form the intercostal arteries , arteries of the arms and legs, lumbar arteries and the lateral sacral arteries. Branches to the sides of the aorta will form the definitive renal , suprarenal and gonadal arteries. Finally, branches at the front of the aorta consist of the vitelline arteries and umbilical arteries. The vitelline arteries form the celiac , superior and inferior mesenteric arteries of the gastrointestinal tract.
After birth, the umbilical arteries will form the internal iliac arteries. The human venous system develops mainly from the vitelline veins , the umbilical veins and the cardinal veins , all of which empty into the sinus venosus. About About 1. The hemoglobin molecule is the primary transporter of oxygen in mammals and many other species. These include a number of cardiovascular diseases , affecting the cardiovascular system, and lymphatic diseases affecting the lymphatic system.
Diseases affecting the cardiovascular system are called cardiovascular disease. Many of these diseases are called " lifestyle diseases " because they develop over time and are related to a person's exercise habits, diet, whether they smoke, and other lifestyle choices a person makes.
Atherosclerosis is the precursor to many of these diseases. It is where small atheromatous plaques build up in the walls of medium and large arteries. This may eventually grow or rupture to occlude the arteries. It is also a risk factor for acute coronary syndromes , which are diseases that are characterised by a sudden deficit of oxygenated blood to the heart tissue.
Atherosclerosis is also associated with problems such as aneurysm formation or splitting "dissection" of arteries. Another major cardiovascular disease involves the creation of a clot, called a "thrombus". These can originate in veins or arteries. Deep venous thrombosis , which mostly occurs in the legs, is one cause of clots in the veins of the legs, particularly when a person has been stationary for a long time.
These clots may embolise , meaning travel to another location in the body. The results of this may include pulmonary embolus , transient ischaemic attacks , or stroke. Cardiovascular diseases may also be congenital in nature, such as heart defects or persistent fetal circulation , where the circulatory changes that are supposed to happen after birth do not.
Not all congenital changes to the circulatory system are associated with diseases, a large number are anatomical variations. The function and health of the circulatory system and its parts are measured in a variety of manual and automated ways.
These include simple methods such as those that are part of the cardiovascular examination , including the taking of a person's pulse as an indicator of a person's heart rate , the taking of blood pressure through a sphygmomanometer or the use of a stethoscope to listen to the heart for murmurs which may indicate problems with the heart's valves.
Cardiovascular system (heart) anatomy
The circulatory system consists of three independent systems that work together: the heart cardiovascular , lungs pulmonary , and arteries, veins, coronary and portal vessels systemic. The system is responsible for the flow of blood, nutrients, oxygen and other gases, and as well as hormones to and from cells. An average adult has 5 to 6 quarts 4. The heart is a muscular organ with four chambers. Located just behind and slightly left of the breastbone, it pumps blood through the network of arteries and veins called the cardiovas- cular system. The systemic circulation is a major portion of the circulatory system.
This page has been produced in consultation with and approved by: use. A person with amyloidosis produces aggregates of insoluble protein that cannot be eliminated from the body. When a person is anaemic, the red blood cells have to work harder to get oxygen around the body. An aneurysm may have no symptoms until it is either very large or it ruptures. Aortic stenosis may be congenital present from before birth , but is often diagnosed during teenage years. Bleeding may be minor or it may be a life-threatening medical emergency.
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The cardiovascular system can be thought of as the transport system of the body. This system has three main components: the heart , the blood vessel and the blood itself. Blood can be thought of as a fluid which contains the oxygen and nutrients the body needs and carries the wastes which need to be removed.
The organs of the circulation angiologia include the bloodvascular system and the lymphatic system.
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