Use the Following Answer Code to Indicate Which Factor Involved

question 242

Multiple Choice

Use the following answer code to indicate which factor involved in the initiation and spread of cardiac excitation is being identified.
-Is the normal pacemaker of the heart.

• A)SA node
• B)AV node
• C)Bundle of His and Purkinje system
• D)Gap junctions

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Definitions:

Spatial Summation

A mechanism in neural communication where multiple presynaptic neurons together stimulate a postsynaptic neuron to threshold, causing it to fire an action potential.

Synaptic Terminal

The end part of an axon that makes a synaptic contact with another neuron or with a muscle or gland cell.

Voltage-Gated Potassium Channels

Proteins that form channels in cell membranes, allowing potassium ions to pass in response to changes in membrane potential, crucial for electrical signaling in neurons.

Methimazole

A medication used to treat hyperthyroidism by inhibiting the production of thyroid hormones.