Notes, Exercises, Videos, Tests and Things to Remember on Heart
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It is the major pumping organ associated with the circulatory system. Human heart contains four chambers, upper two are called Auricles and are divided by an auricular septum into left and right and lower two are called ventricles divided into two by the ventricular septum into left and right. In mammalian heart right side is responsible for collecting impure blood and left side is responsible for collecting pure blood.
One thin membrane covers the heart externally that is called pericardial membrane. The cavity between this membrane and heart wall is called pericardial cavity that is filled with thick, gelatinous fluid called pericardial fluid. Pericardial fluid protects the heart from external injury, keeps heart moist and makes movement heart frictionless.
Wall of right atrium contains natural pacemaker from where the waves of contraction of the heart start. The heart pumps blood with the help of regular contraction and relaxation. During circulation blood flows following route:
Impure blood in right auricle ----- >Right ventricle ( by opening of Tricuspid valve) ------> Pulmonary artery (by the opening of pulmonary valve) -------> Lungs ( Oxygenation) -------> Pulmonary vein ------> Left auricle ------> Left ventricle ( by opening of bicuspid valve) -------> Aorta ( by opening of Aortic valve) -------> tissues of body (exchange of gases and waste products) --------> Vena cava -------> Right auricle
One function of right ventricle is: It pumps deoxygenated blood through pulmonary artery to the lungs for oxygenation (purification). One function of left ventricle is: It pumps the oxygenated blood through pulmonary arteries to different parts of the body to supply oxygen for respiration.
Left ventricle needs to pump blood to all parts of the body whereas right ventricle needs to pump the blood only to the lungs for oxygenation. As the left side needs to pump the blood to a further distance it has thicker and more muscular wall to exert high pressure.
Contraction and relaxation of heart muscles in order to receive and pump blood one is called a heartbeat. A healthy adult's heart beats for about 60-100 times per minute. Heartbeat varies from person to person. The factors that affect the heartbeats are- age, sex, occupation, physical work, mental tension, etc.
The right part of the heart receives the impure blood whereas the left part of the heart receives the pure blood.
Aortic valve lies between the aorta and left ventricle. When the left ventricle squeezes, the valve shuts down and the blood flows forward. But if the valve is not present, the blood flows backward and its absence stops the blood circulation.
The heart is surrounded by two delicate membranes called pericardial membranes. Between these membranes, there is a fluid which is called pericardial fluid.
The functions of pericardial fluid are as follows: -
|Tricuspid valve||Bicuspid valve|
Right auricle collects the large amount of impure blood from different parts of the body through superior venacava and inferior venacava. In the left auricle, the less amount of pure blood is collected from the lungs through pulmonary vein. So, right auricle is bigger than left auricle.
The right ventricle has to pump blood for short distance i.e. from heart to the lungs. But the left ventricle has to pump blood for a very long distance inside our body, for which great pressure is required. Due to it, the wall of left ventricle is thicker than that of right ventricle.
Veins contain valves which open toward heart. Valves are present in there to prevent back flow of blood. Thus, the blood does not flow in the wrong direction.
Which carry oxygenated blood from lungs to the left auricle of the heart?
Which cavity first receives deoxygenated blood from the vena cava?
The wall that divides the heart in two is called ______.
______ transports deoxygenated blood from different parts of the body into the right auricle of the heart.
______ carries pure oxygenated blood from the left ventricle of the heart.