Question

9. During ventricular ejection: e. What is happening to the contractile myocardial cells of the ventricles?

Answer 1

the heart pumps blood through the body by its conduction system:

ventriculer ejection is the part of the pumping of yhe blood.

​​​​​here we start the explanation of the conduction system:

• This is accomplished by contractions and relaxation of the cardial muscle tissue in the myocardium layer.
• Intercalated discs allow impulses to travel rapidly between adjacent cells so they function as one or rather than individual cells

Cardiac Muscle Tissue ted

EVENTS OF CARDIAC CYCLEA

1. Atrial events

2. ventricular events

phases of the cardiac cycle

phase 1:- atrial contraction

phase 2;- isovolumetric contraction

phase 3:- rapid ejection

phase 4:- reduced ejection

phase 5:- isovolumetric relexation

phase 6 :- repid filling

phase 7 :-reduced filling

in this question,

In the phase 3, repid ejection of the ventricular's explanation is below ....

• ​This phase represents intial, rapid ejection of blood into the arota and pulmonary arteries from the left ventricles, respectively
• ejection begins when the intraventricular pressure exceed the pressure within the arota and pulmonary artery, which causes the arotic and pulmonic valves to open.
• Arotic and pulmonary valves open;
• Av valves remain closed.
• No heart sounde are ordinarily noted during ejection because the opening of healthy valves is silent
• Left atrial pressure initially decrease as the atrial base is pulled downward, expanding the atrial chamber by myocardial cells.
• blood continues to flow into the atria frok their respective venous inflow tracts and the atrial pressure being to rise

​​​​​​here, pahse 4 is start ..

..During this pahse

• cells in the AV node conduct impulses more slowly , so there is a delay as implues travel through the node.
• This allows time for atria to finish contraction befor ventricles begun contracting
• ​​

​​​​​​​

Left Atrium Sinoatrial Node (SAN) Right Atrium Atrioventricular Node (AVN) HIS Bundle Left Bundle Branch (LBB) Left Posterior Fascicle (LPS) Right Bundle Branch (RBB) Left Ventricle Left Anterior Fascicle (LAÐ Right Ventricle Purkinje Fibers (PF Septum Cardiac Conduction System

• "BUNDLE OF HIS"
• from THE av nodes impulses travel through to the right and left bundle branches
• These beaches extended to the right and left sides of the septum and bottom of the heart.
• These branch a lot to from the purkinje fibers that transmit the implues to the myocardium
• The bundle of his, bundle branches and purkinje fibers transmit quickly and cause both ventricle to contract at the same time like a phone trees
• As the ventricular contract blood is forced out through the semilunar valves into the pulmonary trunk and the aorta.
• After ventricular complete thier contraction phase, they relax and the SA node initiates another impulse to start cardiac cycle