Which of the Following Statements Regarding the Muscularis Externa of the Esophagus

question 62

Multiple Choice

Which of the following statements regarding the muscularis externa of the esophagus is true?

• A) The upper third portion of the esophagus consists of smooth muscle, the middle third portion is a mixture of smooth and skeletal muscles, and the lower third consists of skeletal muscle.
• B) The entire muscularis of the esophagus consists of skeletal muscle only.
• C) The entire muscularis of the esophagus consists of smooth muscle only.
• D) The upper third portion of the esophagus consists of smooth muscle, and the remaining portion is a mixture of skeletal and smooth muscles.
• E) The upper third portion of the esophagus consists of skeletal muscle, the middle third portion is a mixture of skeletal and smooth muscles, and the lower third consists of smooth muscle.

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Definitions:

Duong Van Minh

A Vietnamese military officer and politician who played a key role in the events leading up to the fall of Saigon and the end of the Vietnam War, briefly serving as South Vietnam's president in 1975.

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The Central Intelligence Agency, a U.S. federal agency responsible for conducting intelligence and counterintelligence activities abroad.

Operation Rolling Thunder

A campaign of extensive aerial bombing conducted by the United States during the Vietnam War.

NLF Fighters

Members of the National Liberation Front, a South Vietnamese communist-led organization and guerrilla force that fought against the United States and South Vietnamese governments during the Vietnam War.