If the Pacemaker Cells in the SA Node Become More

question 65

Multiple Choice

If the pacemaker cells in the SA node become more permeable to potassium ions, the

• A) heart rate will increase.
• B) heart rate will decrease.
• C) cells will depolarize.
• D) cells will hyperpolarize.
• E) heart rate will decrease and cells will hyperpolarize.

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Definitions:

Inhibitory Neurotransmitter

Chemical substances released by neurons in the brain to decrease the activity of other neurons, thus reducing excitability and preventing overstimulation.

GABA

A major inhibitory neurotransmitter in the brain involved in reducing neuronal excitability throughout the nervous system.

Voluntary Movements

Movements that are consciously controlled by the brain, involving motor planning and execution.

Acetylcholine

A neurotransmitter in the nervous system involved in muscle activation, memory, and learning.