Cardiac Muscle Cell

Cardiac Muscle Cells (cardiomyocytes)

Classified under the Skeletal Muscle Tissue

Function:
In the heart there are two types of cells, cardiomyocytes and the cardiac pacemaker cells. the cardiomyocytes make up the valves in the heart such as the atria and the ventricles and are responsible for the contracting and expanding of the heart. They are crucial in the proper beating and pumping of blood that the heart is responsible for. The cardiac pacemaker cells carry the electrical impulses that control the frequency of the beating of the heart.

Structure:
The cardiac cells are striated (striped) and contain a single nucleus and multiple mitochondria. The cardiac muscles cells have a unique branched shape that allows them to be in constant contact with 3-4 other cardiac muscle cells. At the end of each of the cardiac muscle cells are membranes called the intercalated disks. These form tight unions with the neighboring cells so that the cardiac muscle cells do not separate when pumping the blood. Inside the cardiac muscle cell there are thick dark filaments of myosin that are layered upon thin filaments of a light colored protein called actin. When the muscle fibers contract the myosin pulls together the actin fibers and contracts the cell.




sources:
https://en.wikipedia.org/wiki/Cardiac_muscle_cell

http://www.innerbody.com/image_musc01/musc71.html

https://upload.wikimedia.org/wikipedia/commons/7/7e/1020_Cardiac_Muscle.jpg

http://www.getbodysmart.com/ap/circulatorysystem/heart/anatomy/cardiac_muscle/tutorial.html