Question

explain heart structure

Answer 1

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.

Answer 2

$\huge\mathfrak\red{Answer :}$


$\underline{\textbf{Structure :}}$

→ Heart is a hollow, muscular organ present in between two lungs in the thoraric cavity. It's size is about one's fist. It is 12 cm long and 6 cm wide.

→ It's weight in male is 300 gm and 250 gm in female. It's is reddish brown in colour. 

→ It's upper broad part is known as base and lower part is known as Apex. 

→ It's is protected by a double members called pericardium, comprising inner visceral pericardium and outer parietal pericardium.

→ Between these layers there is a fluid called pericardium fluid. This fluid provides moisture to the heart and reduce the friction between heart wall and surrounding tissue.

→ A human heart is four chambered. Two upper; smaller chambers called atria and the lower; longer chambers called ventricle.

→ The atrium and ventricle of the same side are separated by atrio-ventricular septum.

→ Atrial septum separates the left and right atria. Inter ventricular septum separates the left and right ventricles.

→ The opening between right atrium and ventricle is guarded by a valve called Tricupsid valve.

→ And the opening between left atrium and ventricle is guarded by a Bicuspid valve.

→ Valves prevent the backward flow of blood and allow the blood to flow in one direction only.

$\underline{\textbf{Function :}}$

→ It's main function is pumping the blood.

→ It contains two types of blood i.e. Oxygenated and Deoxygenated.

* Oxygenated is send to all parts of the body.

* Deoxygenated is send to lungs to purify it.
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