StudentShare
Contact Us
Sign In / Sign Up for FREE
Search
Go to advanced search...
Free

Discuss the events of one cardiac cycle (electrical and mechenical events) - Essay Example

Cite this document
Summary
The cardiac cycle refers to the flow of blood or blood pressure that begins with one heart beat to the next, and is coordinated by a sequence of impulses that are either mechanical or electrical. From a mechanical perspective, the cardiac cycle is due to movement of blood. The…
Download full paper File format: .doc, available for editing
GRAB THE BEST PAPER92.2% of users find it useful
Discuss the events of one cardiac cycle (electrical and mechenical events)
Read Text Preview

Extract of sample "Discuss the events of one cardiac cycle (electrical and mechenical events)"

The Cardiac Cycle The cardiac cycle refers to the flow of blood or blood pressure that begins with one heart beat to the next, and is coordinated by a sequence of impulses that are either mechanical or electrical. From a mechanical perspective, the cardiac cycle is due to movement of blood. The frequency of the contraction and relaxation of the cardiac muscles is referred to as the heart beat. The cardiac is a special muscle that contracts continually without taking a break, and the importance of the cycle is to maintain blood flow to an individual and supply blood pressure to ensure adequate circulation.

Cardiac muscles are myogenic, which means that their contractions are started by the muscle itself, the action beginning from the sino-atriol node. The first stage of the cardiac cycle is known as the ventricular filling, which involves the flow of blood from the atria to the ventricles. The other stages include the movement of blood from the right ventricle through the pulmonary artery and the left ventricle through the aorta (Guyton and Hall, 2006). The contraction of the heart muscles on the left and right atria, which contract at the same time, is known as the atria systole (Klabunde, 2012).

The events begin with the electrical current, which stimulates the myocardium contracts the heart chambers. This is then followed by the mechanical events. The electrical currents of the heart begin at the Sino atria node where action potential is generated (Williams, 2001). In the Sino-atria node, there is a rich supply of cells, capillaries and nervous supply, and the electrical current travels across the right and left atria. The atria are separated from the ventricles by a non-conducting band of connective tissues.

Between the cardiac muscles are disc called gap junctions that provide electrical resistance at a low rate. The stimulation of each muscle fiber causes an electrical current to pass over the whole heart hence no external stimulus is required. The wave reaches the atrio-ventricular nodes in the lower right atrium, where it delays for a short period of time before conduction to the ventricles through the bundles up the purkinje fibers (Klabunde, 2004). Delaying at the atrio-ventricular node allows enough time for blood in the atria to get into the right ventricles.

The atrio-ventricular node may act as a pace maker, which makes the action potential slow and unstable, depolarization occurs constantly due to the fall of calcium and potassium ions and this effect on the resting potential affects the heart rate.The mechanical sequences of the cardiac cycle are brought on by the rhythmic changes in the cardiac muscles, which include the relaxation and contraction of the muscle (Waxman, 2006). The mechanical events of the cardiac cycle in the left side of the heart include changes in pressure in the aorta and in the left ventricle, heart sounds and change in blood volume.

Contractions begin when the ventricles are excited and cause an increase in the pressure in the ventricles, after which the atria ventricular valves close causing a heart sound. The chambers of the ventricles then become closed, after which there is iso-volumetric contraction where the pressure increases rapidly becoming more than the pressure in the pulmonary artery and aorta, hence opening the semi lunar valve. ReferencesGuyton, A.C. and Hall, J. E. 2006. Textbook of Medical Physiology. Philadelphia: Elsevier.

Klabunde, R. 2004. Cardiovascular Physiology Concepts. Boston: Lippincott Williams & Wilkins.Klabunde, R. 2012. Cardiac Cycle. [Online]. Available Waxman, S. 2009. Clinical Neuroanatomy. Boston: McGraw-Hill Medical. Williams, G. 2001. Advanced Biology for You. New York: Nelson Thornes.

Read More
Cite this document
  • APA
  • MLA
  • CHICAGO
(“Discuss the events of one cardiac cycle (electrical and mechenical Essay”, n.d.)
Retrieved from https://studentshare.org/biology/1598524-discuss-the-events-of-one-cardiac-cycle-electrical-and-mechenical-events
(Discuss the Events of One Cardiac Cycle (electrical and Mechenical Essay)
https://studentshare.org/biology/1598524-discuss-the-events-of-one-cardiac-cycle-electrical-and-mechenical-events.
“Discuss the Events of One Cardiac Cycle (electrical and Mechenical Essay”, n.d. https://studentshare.org/biology/1598524-discuss-the-events-of-one-cardiac-cycle-electrical-and-mechenical-events.
  • Cited: 0 times

CHECK THESE SAMPLES OF Discuss the events of one cardiac cycle (electrical and mechenical events)

Action Potentials and the Cardiac Cycle

This work called "Action Potentials and the cardiac cycle" describes an action potential, the components of an action potential.... The author takes into account the process of potential result in muscular contraction, and also the role of cardiac cycle.... nbsp;  … Seeley, Stephens, and Tate (2007) further explicated that action potentials in cardiac muscles, just like the skeletal muscles and neurons, are characterized by depolarization followed by repolarization, only that cardiac muscles do have a period of slow repolarization, which, in turn, causes a prolongation of the action potential....
5 Pages (1250 words) Assignment

Event Leadership

the events industry is a growing industry which requires individuals to arrange events ranging from birthday parties to political fund raising and corporate conferences.... The cycle includes but… The jobs or people who are involved in this cycle include: Event producer: This can be a team from a company or an individual who draws the concept at the proposal phase of the event with The role of the event producer is a major one and usually inter-links with the event manager....
5 Pages (1250 words) Research Paper

Basic Principles of Magnetic Resonance Image Production

As far as human tissue interactions are concerned, the most worrisome interactions are with blood flow, ears and cardiac cycle (De Wilde et al, 2007).... The term paper "Basic Principles of Magnetic Resonance Image Production" states that Unlike CT imaging and X-ray imaging, though Magnetic Resonance Imaging or MRI was considered to be a safe imaging technique due to the absence of exposure to radiation....
8 Pages (2000 words) Term Paper

Cardiac Function And Physiology

The paper "cardiac Function And Physiology" explains the function, physiology, and effects on homeostasis for other organ systems and makes conclusions from discovery.... The end of the paper will show indices of cardiac function, preload, contractility indexes and a host of physiology related information in support of the mechanics of the heart and how the above is measured....
10 Pages (2500 words) Research Paper

Mega-Events and Modernity

one of the primary reasons for watching movies is just for the fun and pleasure involved in the overall experience.... Then there are people who perceive the experience of watching movies… However, it goes without saying that though movies are readily associated with pleasure, relaxation and fund, they also tend to have an educational appeal and relevance....
18 Pages (4500 words) Essay

Event Risk Management Drills

The New York New Years Eve is one hectic event to be managed by any event risk manager.... The event is hosted at Times Square; a major transportation hub at the heart of the city which can accommodate… The party attendees mostly youth consume a lot of alcohol, can easily form a mob, expose themselves to nudity and perform stunts that are unreasonably deadly....
6 Pages (1500 words) Assignment

Effect of Exercise on Skeletal Muscle

Fast to slow transformations can be artificially induced in an isolated muscle by providing electrical stimulation mimicking a frequency pattern which is more suitable for slow muscle.... umerous studies have been conducted on this aspect and this study (Mei Yu, et al, 2002) in particular focuses on MAPK and AMPK cascades by comparing them in volunteers chosen from two groups, one group involving highly trained cycling athletes and the other one of normal/control persons, by subjecting them to pre-calculated equivalent exercise stress according to their capacities, to further differentiate if there are any changes in the cascades between the two groups....
13 Pages (3250 words) Coursework

Fire Safety Engineering Issues in Formosa Plastics Corporation and the Hotel in Cardiff

The fire explosion case study took place in October 2005 in Texas in one of the production units of Formosa Plastics Corporation.... The fire explosion case study took place in October 2005 in Texas in one of the production units of Formosa Plastics Corporation.... This shows that there was a proper communication structure that ought to be in a building in case one discovers a fire-related incident....
13 Pages (3250 words) Case Study
sponsored ads
We use cookies to create the best experience for you. Keep on browsing if you are OK with that, or find out how to manage cookies.
Contact Us