structure of heart explain
Answers
Explanation:
The human heart is a four-chambered muscular organ, shaped and sized roughly like a man's closed fist with two-thirds of the mass to the left of midline. The heart is enclosed in a pericardial sac that is lined with the parietal layers of a serous membrane.
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Answer:
Explanation:
The human heart is a pumping organ and has four chambers.The two upper ones are called right and left atria.............. The left atrium is smaller than right atrium..
Each atrium has an appendage called auricle. The auricle increases the atrium's surface area.
The two lower chambers are called right and left ventricles.
All four chambers have strong muscular walls. The walls of the two auricles are thinner than those of ventricles as they have to force blood into the two ventricles.The wall of right ventricle is thick as it as to force blood into lungs which are located close to heart. The walls of left ventricle are much thicker because it has to pump blood to all parts of the body.
There is a muscular partition in the middle of the heart called septum which divides it into right and left half, two halves having no connection with each other.
The two auricles are separated by intraauricular septum, similarly two ventricles are separated by intraventricular septum.
The walls of the four chambers of heart are composed of a special type of muscle called cardiac muscle or myocardium which contracts rhythmically and are involuntary. These are striated and are constructed of many small fibres called myofibrils
The Valves Of the Heart---
Tricuspid Valve ---
The opening between the right auricle and right ventricle is guarded by Tricuspid Valve which is made of three flaps of connective tissue.When the ventricle becomes filled with blood the flaps of the valve close the aperture between the auricle and ventricle to prevent the back flow of blood when ventricle contracts.
Bicuspid Valve ---
The valve between the left auricle and the left ventricle is called the bicuspid valve and has only two flaps.It functions same as the tricuspid valve. It allows one way flow of blood from left auricle into left ventricle.