Define autoexcltatory Using the word bank below write down t

Define autoexcltatory: Using the word bank below, write down the chain of events that occur during the conductance system. What do the P, QRS, and T w ave represent on an EKG (ECG)? Which wave represents repolarization of atria? What does the distance between the P and the QRS wave on the EKG signify? What does it mean when a P wave is spread over a longer distance than normal?

Solution

3. The neurons which do not require an external stimulus for excitation are called autoexcitatory.

4. SA node - Atrial muscle fibres (Atria contract) - AV node - AV bundle - Right and left AV bundle branches - Purkinje fibres - Conducts impulses to muscle fibres of both ventricles - Ventricles contract

5. P wave - Conduction of electrical impulse throughout the atria

QRS wave - Spread of electrical activity throughout the ventricular myocardium

T wave - Signifie repolarization of the ventricles

Atrial repolarization occurs during QRS wave, but is obscure. Distance between P and QRS wave mean that there is some problem with the spread of electrical current to the ventricles. Maybe a problem with AV node or Purkinje fibres. When P wave is spread more than normal, it may mean that the SA node may be malfunctioning or the atrial muscles are unable to depolarize properly.