Question

Write a long note on Human heart.​

Answer 1

Answer:

$\huge\boxed{ \mathfrak \red{ \underline{ \underline{ \underline{ \underline{Human \: Heart}}}}}}$

• Heart is a muscular organ responsible for pumping blood through blood vessels by repeated contractions. The term "cardiac" means "related to the heart". The bulk of the walls of heart chambers is made of cardiac muscle.

• In human body, heart is situated between lungs, in the middle of chest cavity (thorax) under breastbone.

• Heart is enclosed ina sac known as pericardium. There is a fiuid, known as pericardium fluid, between pericardium and heart walls. It reduces friction between pericardium and heart, during heart contractions.

• Human heart consists of four chambers, like the heart of birds and other mammals. The upper thin-walled chambers are called left and right artia (singular 'atrium and the lower thick-walled chambers are called left and right ventricles. Left ventricle is the largest and strongest chamber in heart.

• Human heart works as a double pump. It receives deoxygenated (with less oxygen blood from body and pumps it to lungs. At the same time, it receives oxygenated (with more oxygen) blood from lungs and pumps it to all body. Inside heart chambers, the deoxygenated and oxygenated bloods are kept separated. Here is a brief description of the circulation of blood inside heart to show its double-pump mechanism.

• Right atrium receives deoxygenated blood from body via main veins i.e. superior and inferior vena cavae. When/ right atrium contracts it passes the deoxygenated blood to right ventricle. The opening between right atrium and right ventricle is guarded by a valve known as tricuspid valve i(because it has 3 flaps). When right ventricle contracts , the blood is passed to pulmonary trunk, which carries blood to lungs. Tricuspid valve prevents the backflow of blood from right ventricle to right atrium. At the base of pulmonary trunk, pulmonary semilunar valve is present which prevents the backflow of blood from pulmonary trunk to right ventricle.

• The oxygenated blood from lungs is brought by puimonary veins to left artium. Left atrium contracts and pumps this blood to left ventricle.The opening between left atrium and left ventricle is guarded bya valve known as bicuspid valve(because it has two flaps). When left ventricle contracts, it pumps the oxygenated blood in aorta, which carries blood to all parts of body (except lungs). Bicuspid valve prevents the backflow of blood from left ventricle to left atrium. At the base of aorta, aortic semilunar valve is present which prevents the backilow of blood from aorta to left ventricle.

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