Use Of Heart Cells In The Studies Of Cardiac Function

摘要

The heart is a muscular organ responsible for propelling blood throughout the body. The contraction of heart delivers nutrients to and removes wastes from each organ. The heart also provides for the transport of hormones, neurotransmitters, and other messengers between various regions of the body. Heart muscle impairment therefore links to higher stroke risk. The heart cell, also called cardiac myocyte, is the functional unit of heart. Compared with other muscle cells (i.e., skeletal and smooth muscle cells), cardiac muscle cells have their own very unique characteristics. Neither the initiation nor conduction of the signal that activates the heart involves nervous tissue. Instead, some specialized heart cells initiate an electrical signal which is then propagated throughout the heart by other myocardial cells that are specialized for conduction. The contraction, conduction and excitation of heart cells are controlled by different ion channels in the cell membrane. The opening of these channels is orchestrated in response to the electrical signal generated from the specialized heart cells. When the precise balance of ion channels is disturbed for some reasons (e.g. in a heart attack), arrhythmias occur. This disrupts synchronization of cardiac muscle. In patients suffering from myocardial infarction or heart failure, cardiac arrhythmias and the uncoordinated contraction are the major causes of mortality.