Structure of Human Heart | Anatomy of Heart | Biology

Internal and external structure of human heart : anatomical structure of heart is explained in this video describing the location and function of a human heart along with the flow of blood and importance of valves in maintaining the direction of blood flow
What is the structure of a human heart?

Have you ever felt pumping sound in your chest? We hope so because it’s a real life saver.
What are we talking about?

Your heart of course!

Heart forms a circulatory system or blood vascular system along with a network of closed branching blood vessels and blood.

The heart is a mesodermally derived organ, situated in the thoracic cavity, in between the two lungs, slightly tilted to the left. It has the size of a clenched fist and it is protected by a double-walled membranous bag called pericardium which encloses the pericardial fluid. Our heart has four chambers, two relatively small upper chambers called atria and two larger lower chambers called ventricles. A thin, muscular wall called the interatrial septum separates the right and the left atria.
Whereas a thick-walled, the inter-ventricular septum, separates the left and the right ventricles.
The atrium and the ventricle of the same side are also separated by a thick fibrous tissue called the atrioventricular septum.
However, each of these septa are provided with an opening through which the two chambers of the same side are connected. The opening between the right atrium and the right ventricle is guarded by a valve formed of three muscular flaps or cusps called tricuspid valve. Whereas a bicuspid or mitral valve guards the opening between the left atrium and the left ventricle. The openings of the right and the left ventricles into the pulmonary artery and the aorta respectively are provided with the semilunar valves. The valves in the heart allow the flow of blood only in one direction it means they prevent any backward flow.
The entire heart is made of cardiac muscles. The walls of ventricles are much thicker than that of the atria. A specialised cardiac musculature called the nodal tissue is also distributed in the heart.
A patch of this tissue is present in the right upper corner of the right atrium called the sino-atrial node (SAN). Another mass of this tissue is also present in the lower left corner of the right atrium close to the atrioventricular septum called the atrioventricular node (AVN). A bundle of nodal fibres, atrioventricular bundle (AV bundle) continues from the AVN which passes through the atrioventricular septa to emerge on the top of the interventricular septum and immediately divides into a right and left bundle.

These branches give rise to minute fibres throughout the ventricular musculature of the respective sides and are called Purkinje fibres. These fibres along with right and left bundles are known as the bundle of His. The nodal musculature has the ability to generate action potentials without any external stimuli it means it is auto-excitable. However, the number of action potentials that could be generated in a minute vary at different parts of the nodal system. The SAN can generate the maximum number of action potentials which is 70-75 per minute and is responsible for initiating and maintaining the rhythmic contractile activity of the heart.

Therefore, it is called pacemaker.
Our heart normally beats 70-75 times in a minute (average 72 beats per minute).
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Видео Structure of Human Heart | Anatomy of Heart | Biology канала Extraclass Official