Internal anatomy of the human Heart (Explanation of four heart chambers)
There are four heart chambers,they are
- Right atrium
- Right ventricle
- Left atrium
- Left ventricle
Right Atrium
Right atrium receives venous blood from
mainly two source
- The
systemic circuit
- From
the heart muscle itself.
Three major veins empty into the right atrium:
Superior vena cava (SVC) drains venous blood from the head, upper limbs, and superior
regions of the trunk.
Inferior vena cava (IVC) drains blood from the lower limbs and trunk.
Coronary sinus drains blood from the heart wall.
The interatrial septum forms a
wall between the right and left atria.
Right Atrioventricular (AV) Valve
These valve separates the right atrium
from the right ventricle.It is also called as tricuspid valve,and it has three
triangular flaps.Venous blood flows from the right atrium pass through the
valve into the right ventricle. When the right ventricle begins to contract
tricuspid valve closes and it prevent bloodbackflow into the right atrium.
Right Ventricle
Right Ventricle receives deoxygenated
venous blood from the right atrium.The right and left ventricles are separated
by an interventricular septum .
Papillary muscles are present on
the internal wall surface,thsese are cone-shaped, muscular projections and
anchor chordae tendineae ,they are attached to the cusp of the right
atrioventricular valve and prevent everting and flipping of valve into
the right atrium when contracting.
Pulmonary Trunk
At its superior end pulmonary trunk
narrows into a smooth-walled, conical region called the conus arteriosus. The
pulmonary semilunar valve is situated at junction between the end of the right
ventricle and the entrance into the pulmonary trunk.Pulmonary trunk divides
into right and left pulmonary arteries it carry deoxygenated blood to the lungs.
Semilunar Valves
Located within the walls of both
ventricles,seen immediately before the connection of the ventricle to the
pulmonary trunk and aorta.The semilunar valve is composed of three thin,
pocketlike semilunar cusps.When blood is pumped into the arterial trunks, it
pushes against the cusps and forces the valves open. This valve prevent
backward flow of blood into the ventricles,when ventricular contraction ceases.
Left Atrium
Left atrium recieves the oxygenated
blood from the pulmonary veins to the left atrium.
The smooth posterior wall of the left
atrium has openings for approximately four pulmonary veins.
Two left pulmonary veins.
Two right pulmonary veins.
Left Atrioventricular (AV) Valve
Thses valve separates the left atrium
from the left ventricle. This is called as bicuspid valve or the mitral valve.
Left AV valve has chordae tendineae similar to that present in right AV
valve.Oxygenated blood flows from the left atrium into the left ventricle. When
the left ventricle begins to contract the AV valve Is forced closed .They
prevents blood backflow into the left atrium.
Left Ventricle
Left ventricle is largest of the four
heart chambers.Its wall is three times thicker than the right ventricular
wall.The main purpose of thick walls is to generate enough pressure to force
the oxygenated blood from the lungs into the aorta and then through the entire
systemic circuit.The right ventricle only has to pump blood to the nearby
lungs. Trabeculae carneae in the left ventricle are more prominent.There are
two large papillary muscles which attach to the chordae tendineae that help to
support the left AV valve. The aortic semilunar valve is situated at the
junction between the end of the left ventricle and the entrance into the aorta.