What happens in each phase of the cardiac cycle?

Answer 1

What is a cardiac cycle? Cardiac cycle is the term referring to all of the events related to the flow of blood that occur from the beginning of one heartbeat to the beginning of the next. The frequency of the cardiac cycle is the heart rate.

Answer 2

Not sure how in depth you want the answer to be :/. The cardiac cycle is how the heart pumps blood around the body.

There's 3 stages of a cardiac cycle; Atrial systole (the 2 atriums contract pushing blood into the ventricles via the atrioventricular valves (tricuspid and bicuspid valves)) then systole (the ventricles contract pushing the blood up through the semi-lunar valves and into the Aorta (on the left side - to the body) and the pulmonary artery (on the right side) and then diastole (where the heart is at rest.)

Answer 3

The 'first' phase is diastole where the heart's atria and ventricles are relaxing and filling up with blood so the volume starts to increase. Then, atrial systole begins, this is when the atria begin to contract to help push blood through the atrioventricular valves into the ventricle. This phase is initiated by the sinoatrial node (AKA SAN or the pace maker). The SAN initiates a small wave of excitement which passes over the atria causing them to contract. Next, the wave of excitement cannot pass through to the ventricles due to the insulating wall. However, the atrioventricular node (AVN) delays the impulse slightly before allowing it down the Purkyne fibres (found in the septum). The Purkyne fibres carry the impulse to the apex of the ventricles. This causes the ventricles to contract, pushing blood through the semilunar valves and into the arteries. This is ventricular systole.

Answer 4

Phase 0: membrane potential depolarize cause voltage-gated sodium channels to open, increase the flow of sodium ion in to the cell and increasing membrane potential

Phase 1: the open sodium channels begin inactivate, decreasing the flow of sodium ion into the cell causing the membrane potential to fall slightly. At the same time, voltage-gated potassium channels close whlie voltage-gated calcium channel open, increasing the flow of calcium ion into the cell act to depolarize the membrane potential and curb the fall of membrane potential caused by the inactivation of sodium channels.

Phase 2:known as plateau phase, the membrane remains in a depolarized state. potassium channels stay close, calcium channels stay open.

Phase 3: the internal potential gradually falls to more negative. A subtype of potassium channels open, allow signigicant amount of potassium flow out of the cell. The membrane become repolarized cause calcium and sodium channels close. Membrane repolarizes until resting potential is reach

Phase 4:The period of resting potential until the next depolarization.

Answer 5

In the cardiac cycle, during diastole, the heart relaxes and fills with blood. In systole, the heart contracts to push blood out to the body. The atria contract first during atrial systole, followed by ventricular systole where the ventricles contract.

Answer 6

blood cells are madeoxygen goes into the atriumsorry that's all i no from Kelly Linwood(staffs)

Answer 7

All the activites that take place during one complete contraction and relaxation of the cardiac muscle, including the nerve impulse and the closing and opening of its valves.