Once the Threshold Potential Is Reached

question 21

Multiple Choice

Once the threshold potential is reached,

• A)K⁺ channels open.
• B)Na⁺ channels close.
• C)an action potential is inevitable.
• D)the interior of the cell becomes negative with respect to the outside.

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Definitions:

Arcuate Nucleus

A region in the hypothalamus involved in regulating appetite, metabolism, and many other physiological processes.

Thalamus

A major part of the brain serving as a relay station for sensory information, directing it to the appropriate areas of the cortex.

PYY

A hormone involved in digestion and appetite regulation, signaling feelings of fullness.

Digestive Tract

The series of organs in the digestive system through which food passes, nutrients are absorbed, and waste is eliminated.