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in a normally functioning heart, the sa node is the peace maker of the heart, but if it is non functional, than the av node would take over if either the bundle of would take over if either the bundle of his and purkinje fibers can trigger contraction. Each progressive one has a slower instrinsic heart rate
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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.
Where is the only place you can find cardiac muscles?
Cardiac muscle is a type of involuntary striated muscle found only in the walls of the heart. This is a specialized muscle that, while similar in some fundamental ways to smooth muscle and skeletal muscle, has a unique structure and with an ability not possessed by muscle tissue elsewhere in the body. 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 (meaning the can and do beat on their own).
What do heart muscle cells look like?
The cells of heart muscle are striated (like stripes on a tie) as is skeletal muscle. Cardiac muscle is a type of involuntary striated muscle found only in the walls of the heart. They can contract but also carry an action potential (i.e. conduct electricity), like the neurons that constitute nerves. Some of the cells have the ability to generate an action potential, known as cardiac muscle automaticity. That is they beat on their own and in union with each other.
What is the heart muscle cells special feature?
The muscle has unique features that are only in the heart.These muscles are involuntary striated muscle which are only found in the wall of the heart. This is specialised muscle that can contract, 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.Read more: Why_is_the_cardiac_muscle_unusual
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.
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.
How does the cardiac muscle work as a functional syncytium?
cardiac muscle operates as a functional syncytium, although it's not a true syncytium, because each myocardial cell has its own nucleus within its own membrane. Cardiac muscle functions as a syncytium due to the presence of low resistance connections between adjacent cells, and when an action potential is generated, the atria or the ventricle contract together.
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.
