Muscles That Encircle Tubes and Act as Circular Valves Are

question 47

Multiple Choice

Muscles that encircle tubes and act as circular valves are called

• A) frenula.
• B) sphincters.
• C) cannula.
• D) anastomoses.
• E) buccinators.

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Definitions:

Enolate Ion

A negatively charged ion formed by the deprotonation of an alpha carbon to a carbonyl group in an aldehyde or ketone.

Acetophenone

Acetophenone is an aromatic ketone, known as the simplest aromatic ketone, used as a precursor in the synthesis of fragrances and resins.

β-diketone

A type of organic compound containing two keto (carbonyl) groups separated by a carbon atom, often depicted as RC(=O)CH2C(=O)R'.

Enols

Molecules containing a hydroxyl group attached to a carbon atom that is double-bonded to another carbon atom.