Explain human circulatory system
Answers
Answer:
The circulatory system consists of three independent systems that work together: the heart (cardiovascular), lungs (pulmonary), and arteries, veins, coronary and portal vessels (systemic). ... Arteries carry oxygen-rich blood from the heart through the body. Veins carry oxygen-poor blood back to the heart.
Answer:
The circulatory system is responsible for transport of various substances in human beings. It is composed of the heart, arteries, veins and blood capillaries. Blood plays the role of the carrier of substances.
Heart: Heart is a muscular organ; which is composed of cardiac muscles. It is so small that it can fit inside and adult’s fist. The heart is a pumping organ which pumps the blood. The human heart is composed of four chambers, viz. right auricle, right ventricle, left auricle and left ventricle. Systole is the Contraction of cardiac muscles is called systole. Diastole is the Relaxation of cardiac muscles is called diastole.
Arteries are thick-walled blood vessels which carry oxygenated blood from the heart to different organs. Pulmonary arteries are exceptions because they carry deoxygenated blood from the heart to lungs; where oxygenation of blood takes place. Veins are thin-walled blood vessels which carry deoxygenated blood from different organs to the heart. Pulmonary veins are exceptions because they carry oxygenated blood from lungs to the heart. Valves are present in veins to prevent back flow of blood. Capillaries are the blood vessels which have single-celled walls.
Blood: Blood is a connective tissue which plays the role of the carrier for various substances in the body. Blood is composed of plasma, blood cells and platelets. Blood plasma is a pale colored liquid which is mostly composed of water. Blood plasma forms the matrix of blood.
Blood Cells are of two types of blood cells, viz. Red Blood Cells (RBCs) and White Blood Cells (WBCs). Red Blood Corpuscles (RBCs) are red in color because of the presence of hemoglobin which is a pigment. Hemoglobin readily combines with oxygen and carbon dioxide. The transport of oxygen happens through hemoglobin. Some part of carbon dioxide is also transported through hemoglobin. White Blood Corpuscles (WBCs) have a pale white color. They play important role in the immunity. Platelets are responsible for blood coagulation. Blood coagulation is a defense mechanism which prevents excess loss of blood; in case of an injury.
Lymph: Lymph is similar to blood but RBCs are absent in lymph. Lymph is formed from the fluid which leaks from blood capillaries and goes to the intercellular spaces in the tissues. This fluid is collected through lymph vessels and finally returns to the blood capillaries. Lymph also plays an important role in the immune system.
Double Circulation: In the human heart, blood passes through the heart twice in one cardiac cycle. This type of circulation is called double circulation. One complete heart beat in which all the chambers of the heart contract and relax once is called cardiac cycle. The heart beats about 72 times per minute in a normal adult. In one cardiac cycle, the heart pumps out 70 mL blood and thus about 4900 mL blood in a minute. Double circulation ensures complete segregation of oxygenated and deoxygenated blood which is necessary for optimum energy production in warm-blooded animals.
Explanation:
