Cardiac Muscle Tissue and It’s Function
There are different types of muscle tissue in the body. I will be focusing on cardiac muscle tissue and its functions. Cardiac muscle is located in the heart wall and its major function is to pump blood throughout the body. If you were to put cardiac muscle and skeletal side by side you would see that cardiac muscle fibers are shorter in length and less circular. They are described as: “Branched striated fibers with usually only one centrally located nucleus (occasionally two). (Jenkins&Tortora,(2012) p. 132)
Cardiac muscle fibers connect to each other by intercalated discs. Intercalated disc are “Transverse thickenings of plasma membrane called intercalated disc which contain desmosomes and gap junctions.” (Jenkins&Tortora,(2012) p. 132) Desmosomes are the glue of the cardiac muscle they hold it together even through constant athletic movement. For example exercise, if there were no desmosomes in the cardiac muscle it would simple fall apart then minute you jumped on a treadmill or began and exercise routine. “Desmsomes strengthen tissues and hold fibers together during vigorous contractions.” (Jenkins&Tortora,(2012) p. 132) Gap junctions make it possible for action potentials to move through one muscle fiber to the next. “Gap junctions provide route for quick conduction of electrical signals throughout heart.” (Jenkins&Tortora,(2012) p. 132) We don’t have to tell our cardiac muscle to contract it does this all by itself it is called an involuntary muscle. “Cardiac muscle is involuntary and its contractions are not consciously controlled.” (Jenkins&Tortora,(2012) p. 132) For example, could you imagine have to actively tell your heart to beat 24 hours a day? What if you forgot or someone broke your concentration? Your heart muscle would stop beating and you could die depending on how long it took you to actively give your heart the next command. This type of muscle is what keeps us going without us having to consciously think about it. In order for cardiac muscle to contract, myosin pulls the actin filaments together to shrink the muscle cell and make it contract. For example, think of it as an accordion. While each cell is not very strong by itself, millions of cardiac muscle cells working together can easily pump blood in the body through the heart in less than a minute.
Contractions of the heart muscle cells help send blood out to lungs and circulatory systems through the atria and the ventricles. Cardiac muscle cells heavily rely on blood and electrical supply to deliver nutrients and oxygen as well as the removal of waste products like carbon dioxide. The coronary arteries also aid heavily in this function. Cardiac muscle tissue involuntary keeps our heats beating everyday so in many respects it one if not the most important muscle tissue in the human body.

References
Jenkins, G. W. & Tortora, G.J.(2012). Anatomy and Physiology from Science to Life (Third Edition). New Jersey: Wiley.