During the Relative Refractory Period, an Initial Threshold-Level Depolarization Is

question 219

Multiple Choice

During the relative refractory period, an initial threshold-level depolarization is usually not sufficient to trigger an action potential.Why?

• A) Only some Na⁺ channels have returned to their resting position.
• B) Only K⁺ channels are still open, so Na⁺ entry is offset by K⁺ loss.
• C) Only a few K⁺ channels have returned to their resting position.
• D) The statement is incorrect; a threshold-level depolarization always triggers an action potential.
• E) Some Na⁺ channels have returned to their resting position and K⁺ channels are still open, so Na⁺ entry is offset by K⁺ loss.

---

Definitions:

Fixed Manufacturing Expenses

Costs that do not vary with the volume of production, such as rent, depreciation of manufacturing equipment, and salaries of permanent factory staff.

Selling and Administrative Expenses

Expenses incurred from selling products or services and managing the business, excluding production costs.

Variable Selling

Expenses that change in proportion with the volume of sales, such as commissions or shipping costs.

Special Order

An order for goods or services that is outside the company's normal production or service delivery operations.