Fluoride Ions Can Replace Hydroxyl Ions in the Hydroxyapatite Crystal

question 21

Multiple Choice

Fluoride ions can replace hydroxyl ions in the hydroxyapatite crystal lattice of teeth.This fluoridated hydroxyapatite,or fluorapatite,is more soluble and makes the tooth less resistant to demineralization.

• A) Both statements are true.
• B) Both statements are false.
• C) The first statement is true; the second is false.
• D) The first statement is false; the second is true.

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Definitions:

Myelin Sheath

A fatty layer that encases the axons of some nerve cells, facilitating the rapid transmission of nerve impulses.

Axon

A long, narrow outgrowth of a neuron’s cell body that lets the neuron transmit information to other neurons.

Acetylcholine

A neurotransmitter in both the central and peripheral nervous systems involved in muscle activation and memory among other functions.

Antagonist

A substance that blocks or inhibits the effect of a neurotransmitter or hormone, or a character in conflict with the protagonist in literature.