Two Fundamental Concepts About the Ion Channels of a "Resting

question 38

Multiple Choice

Two fundamental concepts about the ion channels of a "resting" neuron are that the channels

• A) are always open, but the concentration gradients of ions frequently change.
• B) are always closed, but ions move closer to the channels during excitation.
• C) open and close depending on stimuli, and are specific as to which ion can traverse them.
• D) open and close depending on chemical messengers, and are nonspecific as to which ion can traverse them.
• E) open in response to stimuli, and then close simultaneously, in unison.

---

Definitions:

Stress-Relaxation Response

A physiological response where muscle tension decreases over time when the muscle is stretched to a fixed length.

Oxygen Tension

The partial pressure of oxygen, an indicator of its concentration in blood or tissues, important for cellular respiration and metabolism.

Adrenal Medulla

The inner portion of the adrenal gland, responsible for producing adrenaline and noradrenaline, which are involved in stress responses.

Vasodilation

is the widening of blood vessels, resulting from relaxation of smooth muscle cells within the vessel walls, often increasing blood flow.