Heart and Blood Circulation
• Animals need food, water and oxygen for their survival. They need to transport all these substances to various parts of their body.
• The circulatory system transports food, water and oxygen from one place to another in the body of an organism. In human beings, transportation is performed by the circulatory system, which is made up of:
• Heart: Itserves as a pump.
• Blood: Itserves as a medium.
• Blood vessels: They serve as tubes.
• Human heart is a muscular organ situated between the lungs in the chest cavity.
• Heart remains enclosed by a double walled sac called pericardium and pericardial fluid is present between both the walls, which protects the heart from shocks and injuries.
• Human heart is a muscular, pumping organ which has four chambers, i.e., right auricle, left auricle, right ventricle and left ventricle.
• Atria or auricles are thin-walled upper chambers, whileventriclesare thick-walled lower chambers.
• Atria receive blood from different organs of the body and pump it into the ventricles. On the other hand, ventricles pump the blood received from the heart to different organs of the body.
• Septum is the partition present between the chambers of the heart that helps to avoid the mixing up of oxygen rich blood with the blood rich in carbon dioxide.
• Valves present between atria and ventricles guard the openings between auricles and ventricles, and allow flow of blood only in one direction.
• There are four valves present inside the heart, which are:
• Tricuspid valve
• Pulmonary semilunar valve
• Bicuspid valve
• Aortic semilunar valve
• Blood vessels are of three types i.e., arteries, veins and capillaries.Two types of blood circulation occur in humans:
• Pulmonary circulation: It is the blood flow from heart to the lungs and then back to the heart.
• Systemic circulation: It is the back and forth flow of blood between the heart and other organs of the body.
• Double circulation is when the blood passes through the heart twice in one cycle of circulation.
• Cardiac cycle is the sequence of events that take place in the heart between two heart beats.
• There are two phases of cardiac cycle:
• Contraction phase or systole, which involves the pumping of blood to various body parts.
• Relaxation phase or diastole in which the heart receives blood from various body parts.
• Rhythmic occurrence of two phases together constitute the cardiac cycle.
• Hepatic portal circulation is the circulation of food laden blood from small intestine to the liver and then to the heart.
• Pulse is the number of times heart beats in one second.
• Blood pressure is the pressure exerted by the blood on the walls of the arteries.
• Sphygmomanometer is an instrument used for the monitoring of blood pressure.
• The two types of abnormal blood pressure arehypotensionand hypertension.
• Other heart related problems include heart palpitations and cardiac arrest.
• Lymphatic system works in union with the circulatory system and consists of lymph vessels and lymph nodes.
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Human heart has ____chambers.Marks:1
Human heart has four chambers; two atria, which are the upper chambers and two ventricles, which are the lower chambers.
The size of human ____is similar to a clenched fist.Marks:1
The size of human heart is similar to your clenched fist and it is slightly tilted to the left.
___is a muscular, pumping organ located on the left side of the chest.Marks:1
Heart is a muscular, pumping organ located on the left side of the chest. It helps in pumping of the blood.
Transportation is performed in humans by _____.Marks:1
In humans, transportation is performed by the circulatory system, which is made up of heart, blood and blood vessels.
Which of the following processes helps to transport the materials from one place to another via some means of transport?Marks:1
Transportation is the process by which materials are transported from one place to another via some means of transport. Food, water and oxygen are necessary for survival and supplied to the various parts of body through transportation.