Preview

Cardiac Cycle

Good Essays
Open Document
Open Document
770 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Cardiac Cycle
Cardiac Cycle
The cardiac cycle describes the coordinated and rhythmic series of muscular contractions associated with the normal heart beat.
The cardiac cycle can be subdivided into two major phases, the systolic phase and the diastolic phase. Systole occurs when the ventricles of the heart contract. Accordingly, systole results in the highest pressures within the systemic and pulmonary circulatory systems. Diastole is the period between ventricular contractions when the right and left ventricles relax and fill.
The cardiac cycle cannot be described as a linear series of events associated with the flow of blood through the four chambers. One can not accurately describe the cardiac cycle by simply tracing the path of blood from the right atrium, into the right ventricle, into the pulmonary circulation, the venous pulmonary return to the left atrium, and finally the ejection into the aorta and systemic circulation by the contraction of the left ventricle. In reality, the cardiac cycle is a coordinated series of events that take place simultaneously on both the right pulmonary circuit and left systemic circuit of the heart.
The cardiac cycle begins with a period of rapid ventricular filling. The right atrium fills with deoxygenated blood from the superior vena cava, the inferior vena cava, and the coronary venous return (e.g., the coronary sinus and smaller coronary veins). At the same time, the pulmonary veins return oxygenated blood from the lungs to the left atrium. During the early diastolic phase of the cardiac cycle, both ventricles relax and fill from their respective atrial sources. The atrio-ventricular valves (the tricuspid valve is located between the right atrium and right ventricle; the mitral valve is between the left atrium and left ventricle) open and allow blood to flow from the atria into the ventricles.
The flow of blood through the atrio-ventricular valves is unidirectional and as volume related pressure increases within the ventricles, the

You May Also Find These Documents Helpful

  • Good Essays

    Chap 18 Case Study

    • 1135 Words
    • 3 Pages

    a. Due to this defect would you expect the blood to move from left-to-right ventricle or right-to-left ventricle during systole? I would expect the blood to move from the left to the right ventricle.…

    • 1135 Words
    • 3 Pages
    Good Essays
  • Satisfactory Essays

    I have decided to focus my essay on the biological cycles that occur inside organisms. The cardiac cycle is vital in all organisms with a heart, to pump blood round the body. There are phases of the cardiac cycle; systole (contraction) and diastole (relaxation). The heart consists of 4 chambers, 2 being the atria at the top of the heart and the other 2 being the ventricles at the bottom of the heart. Systole occurs separately in the atria and ventricles and diastole occurs simultaneously in all 4 chambers. The cardiac cycle is controlled by electrical waves that spread throughout the heart. The blood flows into the heart straight into the atria via the vena cava and pulmonary vein. A wave of electrical activity is firstly spread from the Sino-atrial node which spreads across both atria, this causes the atria to contract which forces blood down into the ventricles through the atrioventricular valves. The atrioventricular septum prevents the wave crossing the ventricles. The wave passes to the atrioventricular node where it is passed down the septum down specialised fibres known as the bundle of His. This occurs after a short delay to allow all the blood to flow from the atria to the ventricles. This wave passes down the bundle of His to the Apex of the heart where the Ventricles contract upward, pumping blood out of the ventricles into the pulmonary artery and aorta through the semilunar valves. Here the blood is then passed round the body where it then returns to the heart and the process repeats.…

    • 504 Words
    • 2 Pages
    Satisfactory Essays
  • Satisfactory Essays

    6. Describe what happens in the cardiac cycle in the following situations. 1. 2. 3. 4. 5. 6. immediately before the P wave: during the P wave: HEART IS IN DIASTOLE…

    • 455 Words
    • 2 Pages
    Satisfactory Essays
  • Satisfactory Essays

    1. List the elements of the intrinsic conduction system in order starting from the SA Node.…

    • 327 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    Path

    • 261 Words
    • 2 Pages

    The path blood take from the right femoral vein to lower lobe of the right lung via the pulmonary artery is as follows; we start in the right femoral vein which is located in the thigh and travel to the right external iliac vein. Blood from the femoral vein emptiness in the inferior vena cava but first must travel through the external iliac. The iliac vein joins with the inferior vena cava. The inferior vena cava takes deoxygenated blood form the lower limbs of the body to the right atrium (Thibodeau, Patton, 2008.). Following the inferior vena cava we travel in to the right atrium of the heart. The purpose of right atrium of the heart is to receive deoxygenated blood from the body through the inferior vena cava and pump it into the right ventricle (MedicineNet.com, 2012). Once we are ready to leave the right atrium we go into the right AV valve (AV is atrioventricular or cuspid, (Thibodeau, Patton, 2008.).The AV valve stops blood from flowing backwards and every time the heart beats the valve opens and closes. The AV valve allows blood to flow into the right ventricle. But before blood goes into the right ventricle it has to travel through the tricuspid valve. The tricuspid valve along with AV and SL are all structures that prevent blood from flowing backwards (Thibodeau, Patton, 2008.). So we now know that the right ventricle receives deoxygenated blood from the right atrium, but what we don’t already know is that the right ventricle sends the... [continues]…

    • 261 Words
    • 2 Pages
    Good Essays
  • Powerful Essays

    cardiac tumors

    • 9291 Words
    • 38 Pages

    The right atrium receives de-oxygenated blood from the body through the superior vena cava (head and upper…

    • 9291 Words
    • 38 Pages
    Powerful Essays
  • Good Essays

    Caleb's Heart Case Study

    • 1245 Words
    • 5 Pages

    During systole, the contraction phase, I would expect the blood in Caleb’s heart to move from left to right ventricle (Marieb & Hoehn, 2015, 685-687).…

    • 1245 Words
    • 5 Pages
    Good Essays
  • Good Essays

    The heart lies in the thoratic cavity, organs associated with the heart are inferiorly, the hearts apex rested on the tendon of the diaphragm, superiorly, the great blood vessels, posteriorly the oesophagus, trachea and the left and right bronchus, laterally, the lungs and anteriorly the sternum and ribs. (Waugh& Grant 2014). The heart provides a constant blood circulation action and the blood vessels provide a network for the blood flow. The heart is the pump responsible for maintaining adequate circulation of oxygenated blood around the vascular network of the body, ( www.le.ac.uk) the right side of the heart pumps blood to the lungs (pulmonary circulation) and the left side receives oxygenated blood and supplies it to the rest of the body (systemic circulation). There are three types of blood vessel, arteries, capilleries and veins. Blood is pumped from the heart through the arteries at high pressure which could damage the tissue so it needs to go through the capillaires which are smaller low pressure blood vessels that are responsilbe for providing oxygen to the tissues, they also absord excess carbon dioxide and then deliver the blood into the veins which then supply the blood back to the heart. The heart generates its own electrical impulses, it does not rely on any other external mechanisn to make it beat. A normal heart rate is 60-80 times per minute, factors which can decrease or…

    • 800 Words
    • 4 Pages
    Good Essays
  • Powerful Essays

    The heart can be described as muscular pump; it’s primary function is to pump blood. The heart consists of four chambers. The upper two chambers are called the atriums and the lower two chambers are called the ventricles. As the heart contracts, blood is pumped through the body with the assistance of four heart valves. Blood that is low in oxygen flows back to the heart after circulating through the body. The blood enters through veins and enters the right atrium. This chamber empties blood through the tricuspid valve into the right ventricle. The right ventricle continues to pump the blood under low pressure through the pulmonary valve into the pulmonary artery. The blood is now directed to the lungs where it gets fresh oxygen. After the blood is oxygenized, the blood will have a bright red…

    • 1888 Words
    • 8 Pages
    Powerful Essays
  • Good Essays

    Answers Lab06 BP

    • 1971 Words
    • 17 Pages

    What event within the heart causes the AV valves to open? Ventricular pressure Ͻ atrial pressure…

    • 1971 Words
    • 17 Pages
    Good Essays
  • Powerful Essays

    Hs131 Unit 4 Assignment

    • 1308 Words
    • 6 Pages

    It then continues as the right external iliac which comes together to the inferior vena cava, also known as the posterior vena cava. It is a vein that carries deoxygenated blood from the lower body to the heart. From there, the inferior vena cava leads to the right atrium of the heart. The right atrium is only one of the four hollow chambers of the heart. It receives blood from the superior vena cava and the inferior vena cava. The blood that comes through these veins is low in oxygen (“Right Atrium”, n.d.). After passing through the right atrium, we pass through the right atrioventricular (AV) valve, also called the tricuspid valve, and then we shall go through the right ventricle, lower right-hand chamber of the heart that pumps blood from the right atrium into the pulmonary arteries then to the lungs, to the pulmonary valve, or the pulmonary semilunar valve. The valves of the pulmonary semilunar valve opens when the right ventricle contracts. When the muscles…

    • 1308 Words
    • 6 Pages
    Powerful Essays
  • Satisfactory Essays

    Cardiovascular Dynamics

    • 818 Words
    • 4 Pages

    1. What happened to the fluid flow rate as the radius of the flow tube was increased?…

    • 818 Words
    • 4 Pages
    Satisfactory Essays
  • Best Essays

    Core Skill: Blood Pressure

    • 2639 Words
    • 11 Pages

    Blood pressure is the pressure exerted against arterial walls during a cardiac cycle (Foxall 2009) The contraction of ventricles is the systolic phase, and the interval in between contractions where the ventricles refill with blood is known as the diastolic phase. During the systolic phase the aorta and large arteries stretch to a certain extent due to a large amount of energy in the vessel whereas in the diastolic phase this energy is then released in a form of elastic recoil. This effect…

    • 2639 Words
    • 11 Pages
    Best Essays
  • Powerful Essays

    5. To recognize that body tissues may differ in their blood demands at a given…

    • 5627 Words
    • 23 Pages
    Powerful Essays
  • Satisfactory Essays

    blood flow back toward the heart due to aortic pressure being greater than interventriuclar pressure…

    • 297 Words
    • 2 Pages
    Satisfactory Essays

Related Topics