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In a normally functioning heart, the SA (sinoatrial) node is the pacemaker of the heart, but if it is nonfunctional then the AV (atrioventricular) node would take over. If it isn't working either then the Bundle of His can trigger contractions, and if it isn't working the Perkinje fibers can trigger contractions. Each progressive one has a slower intrinsic heart rate.
Wiki User
∙ 13y ago
Wiki User
∙ 13y agoIt originates from the Sinoatrial Node at the top of the right atria, and then travels down to the Atrioventricular Node, which is just next to the right Atrioventricular valves. Hope this helps
Wiki User
∙ 13y agoFrom S.A. node cardiac impulse starts.
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Why is the cardiac action potential longer?
The reason why cardiac muscle has a longer action potential is to extend the absolute refractory period to prevent another action potential. If too many action potentials stimulate the cardiac muscle it can get into tetanus which keeps the heart continuously contracted without relaxation.
What effect does hypocalcemia have on the cardiac action potential?
It can prolong the cardiac action potential. It can also have other effects, such as torsades de pointes,and it can mask digitalis toxicity.
What phase of cardiac muscle action potential caused by sodium ions entering cell?
The first phase of a cardiac action potential (or any action potential) involves influx of sodium ions. This phase may be called:The rising phaseThe depolarization phasePhase 0
What is automaticity of the heart?
The property that allows any cell in the cardiac muscle to begin an action potential, or a cardiac conduction, leading to cardiac contraction.
Why do you keep the heart from entering tetanus?
The action potential of cardiac muscle is prolonged consisting of the depolarization spike and plateau and a repolarization period. The action potential causes a long refractory period of about 250-400 milliseconds in the heart.
Action potentials originate at the?
Action potentials are how nerve impulses are transmitted from neuron to neuron. An action potential is formed when a stimulus to the nerve cell causes the membrane to depolarize and open all of its sodium ion channels toward the threshold potential.
What is the function of the intercalated disc?
Basically, the cardiac action potential travel across them, making it easier for the electrical impulses to move quickely.
What is the significance of the plateau phase seen in the action potential of cardiac muscle cells?
calcium channels remaning open.
In cardiac muscle the fast depolarization phase of action potential is the result of?
increased membrane permeability to sodium ions
Allow spread of action potential between cardiac fibers?
Visceral Muscle Tissue or Visceral Smooth Tissue is a cardiac muscle. Its gap junctions allows actions that is likely to disseminate from one cell to another.
The plateau portion of the action potential in contractile cardiac muscle cells is due to?
Slow inward diffusion of Ca2+
Why couldn't your heart have cardiac tissue?
Cardiac muscle, like other muscles, can contract, but it can also carry an action potential (i.e. conduct electricity), like the neurons that constitute nerves. Furthermore, some of the cells have the ability to generate an action potential, known as cardiac muscle automaticity. (Some cells can make the heart beat on its own.) This doesn't occur in any other type of muscle tissue. This ability can keep the heart pumping even under disease conditions.
