Question

Draw a schematic diagram of human heart.

Answer 1

schematic diagram of human heart.

Answer 2

${\blue{\underline {\underline{ \mathtt{\pink{diagram \: of \: heart:-}}}}}}$

${\blue{\fbox{\green{\boxed{\orange{\underline {\underline{\mathcal \purple{Heart \: }}}}}}}}}$

Human Circulatory System

• Humans have a closed circulatory system: Blood pumped by the heart always flows through a closed network of blood vessels.

• Human circulatory system consists of:

• Muscular, four-chambered heart.

• A network of closed, branching blood vessels − veins, arteries and capillaries.

• Blood.

__________________________

• Location: Thoracic cavity in between the lungs; slightly tilted to the left

• Protected by a double-walled pericardium, enclosing the pericardial fluid

• Has 4 chambers: 2 upper chambers − right and left atria
• 2 lower chambers − right and left ventricles

• Inter-atrial septum: Separates the right and the left atria

• Inter-ventricular septum: Separates the right and the left ventricles

• Atrio-ventricular septum: Separates the atria and the ventricles of the same sides

• Septa have openings through which the two chambers on the same sides are connected.

• Tricuspid valve: Present between the right atria and the right ventricle

• Bicuspid (mitral) valve: Present between the left atria and the left ventricle

• Semilunar valves: Guard the openings of the right and the left ventricles into the pulmonary artery and the aorta respectively.

• Special cardiac musculature called nodal tissue is distributed throughout the heart.

• Sinoatrial node (SAN): Present at the upper right corner of the right atrium

• Atrio-ventricular node (AVN): Present at the lower left corner of the right atrium.

AV bundle (a bundle of nodal fibres) continues from the AVN and passes through the atrio-ventricular septa to reach the inter-ventricular septum.

There, it divides immediately into right and left bundles. From these branches, minute fibres arise throughout the ventricular musculature. These fibres are called purkinje fibres.

• Right and left bundles + Purkinje fibres = Bundle of His.

• Significance of nodal musculature: Auto-excitable; generates and maintains action potential to sustain the rhythmic contraction activity of the heart.

• Pacemaker of the heart − Sino-atrial node (SAN).

• Heart beats 70−75 times/min.