Sara B. answered • 06/21/21
Patient Math Tutor for K-12 students!
Hi Josephine!
Voluntary control suggests that the question is asking which of those actions do not involve skeletal muscle since skeletal muscle is voluntary.
a.Defecation
The external anal spincter, which we voluntary relax during defecation is made of skeletal muscle.
B. Stomach emptying
The pyloric sphincter between the stomach and the duodenum is made of smooth muscle.
c. Initiation of swallowing
The first part, or oral phase of swallowing primarily involves the tongue voluntarily pushing the bolus towards the oropharynx and the soft palate rising up to block the nasopharynx. Tongue muscles and palatine muscles are skeletal muscles.
d. Propulsion of small intestine
Peristalsis in the small intestine is the result of smooth muscle contraction. The smooth muscle is in the wall of the small intestine.
Therefore, I believe B and D would be the answers.
