Which of the Following Words Refers to the Soft, Spongy

question 18

Multiple Choice

Which of the following words refers to the soft, spongy, conical organ of the thorax?

• A)Heart
• B)Lung
• C)Mediastinum
• D)Diaphragm
• E)Hilum

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Definitions:

Membrane Receptor

A specialized protein molecule embedded in the cell membrane that can interact with specific molecules, starting a chain of cell responses.

Depolarization

The process in which a cell's membrane potential becomes less negative, moving towards zero, which is critical in the initiation of action potentials.

Threshold Stimulus

Stimulus resulting in a local potential just large enough to reach threshold and produce an action potential.

All-Or-None Contraction

A principle stating that a nerve or muscle fiber responds completely or not at all to a stimulus once the stimulus reaches a threshold value.