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:

Neurotransmitters

Chemical messengers that transmit signals across synapses from one neuron to another in the brain and nervous system.

Knoblike Terminals

The rounded ends of axons, known as axon terminals, which are involved in transmitting signals to other neurons or muscles through the synapse.

Axon

A narrow, lengthy protrusion from a nerve cell responsible for carrying electrical impulses outward from the neuron's main body.

Sensory Information

Data that is collected by the senses (sight, hearing, taste, touch, and smell) and sent to the brain for processing.