Answer: involuntary contraction
Muscle contractions can be described based on two variables: force and length. Force itself can be differentiated as either tension or load. Muscle tension is the force exerted by the muscle on an object whereas a load is the force exerted by an object on the muscle . When muscle tension changes without any corresponding changes in muscle length the muscle contraction is described as isometric.
Cardiac muscle contracts in a similar manner to skeletal muscle although with some important differences.Electrical stimulation in the form of an action potential triggers the release of calcium from the cell’s internal calcium store the sarcoplasmic reticulum.The rise in calcium causes the cell’s myofilaments to slide past each other in a process called excitation contraction coupling.
Cardiac physiology – Wikipedia
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. This process is of vital importance as it allows for the heart to beat in a controlled manner without the need for conscious input. EC coupling results in the sequential contraction of the …
Cardiac muscle cells or cardiomyocytes (also known as myocardiocytes or cardiac myocytes) are the muscle cells that make up the cardiac muscle (heart muscle ). Each myocardial cell contains myofibrils which are specialized organelles consisting of long chains of sarcomeres the fundamental contractile units of muscle cells.
Cardiac muscle tissue has autorhythmicity the unique ability to initiate a cardiac action potential at a fixed rate – spreading the impulse rapidly from cell to cell to trigger t…