Search results
Results from the WOW.Com Content Network
Myocardial contractility represents the innate ability of the heart muscle (cardiac muscle or myocardium) to contract.It is the maximum attainable value for the force of contraction of a given heart.
The mechanisms of contraction in these muscle tissues are similar to those in skeletal muscle tissues. Muscle contraction can also be described in terms of two variables: length and tension. [ 1 ] In natural movements that underlie locomotor activity , muscle contractions are multifaceted as they are able to produce changes in length and ...
T-tubules (transverse tubules) are extensions of the cell membrane that penetrate into the center of skeletal and cardiac muscle cells.With membranes that contain large concentrations of ion channels, transporters, and pumps, T-tubules permit rapid transmission of the action potential into the cell, and also play an important role in regulating cellular calcium concentration.
This protein is found as a pentamer and is a major substrate for the cAMP-dependent protein kinase in cardiac muscle.In the unphosphorylated state, phospholamban is an inhibitor of cardiac muscle sarcoplasmic reticulum Ca 2+-ATPase [7] which transports calcium from cytosol into the sarcoplasmic reticulum.
Cardiac excitation-contraction coupling (Cardiac EC coupling) describes the series of events, from the production of an electrical impulse (action potential) to the contraction of muscles in the heart. [1] This process is of vital importance as it allows for the heart to beat in a controlled manner, without the need for conscious input.
Contraction that squeezes blood towards the exit is more efficient than a simple squeeze from all directions. Although the ventricular stimulus originates from the AV node in the wall separating the atria and ventricles, the Bundle of His conducts the signal to the apex. Depolarization propagates through cardiac muscle very rapidly.
The action potential passes along the cell membrane causing the cell to contract, therefore the activity of the sinoatrial node results in a resting heart rate of roughly 60–100 beats per minute. All cardiac muscle cells are electrically linked to one another, by intercalated discs which allow the action potential to pass from one cell to the ...
As a larger volume of blood flows into the ventricle, the blood stretches cardiac muscle, leading to an increase in the force of contraction. The Frank-Starling mechanism allows the cardiac output to be synchronized with the venous return, arterial blood supply and humoral length, [2] without depending upon external regulation to make ...