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Answer:
D. All of the above
Explanation:
In Human anatomy, cardiac cycle can be defined as a complete heartbeat of the human heart which comprises of sequential alternating contraction and relaxation of the atria and ventricles, therefore causing blood to flow unidirectionally (one direction) throughout the human body.
Generally, the cardiac cycle occurs in two (2) stages;
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Diastole : in this stage, the ventricles is relaxed and would be filled with blood.
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Systole: at this stage, the muscles contracts and thus, allow blood to be pushed through the atria.
Cardiac output can be defined as the volume of blood that is being pumped by the mammalian heart through the left and right ventricle per unit time (minute).
The following conducting systems of the heart cause the ventricles to contract;
I. Atrioventricular (AV) node: it's a component of the electrical conduction system of the mammalian heart located in the Koch triangle which connect the ventricles and atria electrically.
II. Atrioventricular (AV) bundle: it's a specialized tissue that transmits electrical impulse from the atrioventricular (AV) node to the Purkinje fibres of the ventricles.
III. Purkinje fibers: it's a network of specialized cells that comprises of glycogen and they transmit cardiac action potentials in a rapid manner from the atrioventricular (AV) bundle to the myocardium of the ventricles.
Furthermore, the right atrioventricular valve (AV) also referred to as the tricuspid valve is located on the right dorsal side of the human heart. The right atrioventricular valve (AV) comprises of three (3) leaflets (flaps) which opens and closes in order to allow for the flow of blood from the right atrium of the human heart to the right ventricle. Also, the right atrioventricular valve is saddled with the responsibility of preventing blood from flowing backward in the mammalian heart.
What else can I help you with?
What carries electrical impulses across the heart and causes the ventricles contract?
SA node.
The stage of the heart cycle in which the heart muscle contacts and the chambers pump blood?
The sinoatrial node depolarizes the atria and causes them to contract which tops up the ventricles with blood, the signal then moves through the atrioventricular node and then the atrioventricular bundle and into the purkinje fibres which causes the ventricles to depolarize and contract sending blood from the right ventricle to the lungs and from the left ventricle. The Atria repolarizes at the same time as the ventricles depolarize and then a fraction of a second later the ventricles repolarize and the cycle begins again.
What causes the normal delay in transmission at the AV node What is the importance of this delay for cardiac function?
The delay occurs within the fibres of the AV node. It is important because it allows the atria to complete their contraction and empty their blood into the ventricles before the ventricles contract. There is a short delay (1 m/second) in transmission of the impulse to the ventricles.
What happens to A V valves during ventricular contraction?
As the ventricles of the heart contract the pressure in the ventricles rises beyond that of the atria. This pressure differential causes the AV valves to shut.
Atrioventricular node at the bottom of the?
The heart beats regularly because it has it's own pacemaker. The pacemaker is a small region of muscle called the sinoatrial, or SA, node. It is in the upper back wall of the right atrium. The node triggers an impulse that causes both atrium to contract. Very quickly, the impulse reaches the atrioventricular, or AV, node at the bottom of the right atrium. Immediately, the atrioventricular node triggers an impulse that causes both ventricles to contract.
Which structure of the heart provides the stimulation that causes the ventricles to contract?
purkinje fibers
Does the AV node initiates the contraction of the atria?
No, the sinoatrial (SA) node initiates contraction of the atria, which subsequently causes stimulation of the AV node, which then initiates contraction of the ventricles via the Purkinje fibers.
What causes the atrio ventricular valves to close?
The rise in pressure inside the ventricles, when the walls of the ventricles contract.
Weak stimulation of a motor neuron causes the muscle to what?
contract weakly
What carries electrical impulses across the heart and causes the ventricles contract?
SA node.
The stage of the heart cycle in which the heart muscle contacts and the chambers pump blood?
The sinoatrial node depolarizes the atria and causes them to contract which tops up the ventricles with blood, the signal then moves through the atrioventricular node and then the atrioventricular bundle and into the purkinje fibres which causes the ventricles to depolarize and contract sending blood from the right ventricle to the lungs and from the left ventricle. The Atria repolarizes at the same time as the ventricles depolarize and then a fraction of a second later the ventricles repolarize and the cycle begins again.
Which ecg wave must occur before the ventricles can relax?
The T wave on an ECG must occur before the ventricles can relax. This wave represents the repolarization of the ventricles, signifying that they have finished contracting and are now primed for relaxation.
What happens to A-V valves during ventricular contraction?
As the ventricles of the heart contract the pressure in the ventricles rises beyond that of the atria. This pressure differential causes the AV valves to shut.
An electrical signal causes the atria to?
bubble up and popno one knowsthe signal causes the atria to contract.
What is the effect of sympathetic stimulation on the rectum?
Sympathetic stimulation causes relaxation of the rectum's smooth muscle, leading to decreased motility and tone. This can result in decreased urgency and the ability to retain feces.
The SA node triggers an impulse that causes both atria to do what?
SA node sends an impulse for the atria to contract. AV node is then activated which contracts the ventricles.
What causes the normal delay in transmission at the AV node What is the importance of this delay for cardiac function?
The delay occurs within the fibres of the AV node. It is important because it allows the atria to complete their contraction and empty their blood into the ventricles before the ventricles contract. There is a short delay (1 m/second) in transmission of the impulse to the ventricles.
