Which of the Following Statements About Membrane Potentials in Different

question 15

Multiple Choice

Which of the following statements about membrane potentials in different types of cardiac cells is TRUE?

• A) Myocardial cells have a resting membrane potential of about -90 mV; pacemaker cells do not have a true resting membrane potential.
• B) Once threshold depolarization is reached in both myocardial and pacemaker cells, the rapid upswing of the action potential is caused by the opening of voltage-gated Na⁺ channels
• C) Voltage-gated transient (T-type) Ca²⁺ channels are present in all of the different types of cells of the heart.
• D) There are no L-type Ca²⁺ channels in cardiac muscle cells.
• E) The upstroke of the action potential is steeper in SA node cells than it is in Purkinje cells.

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Definitions:

Lower of Cost

An accounting principle that dictates inventory and other assets should be recorded at the lesser of their historical cost or current market value.

Inventory Valuation

The process of calculating the cost assigned to inventory items to determine the cost of goods sold and the inventory asset value at the end of an accounting period.

Weighted Average

A calculation that takes into account the varying weights or significance of different items in a data set, producing a mean value.

Perpetual Inventory System

A method of inventory management that instantly logs sales or acquisitions of inventory using computerized point-of-sale systems and software for managing enterprise assets.