Based on the examination at her doctor's office, a patient is told that her parasympathetic nerves are damaged. Which of the following muscles would most likely be affected?: (A) Muscles in blood vessels, (B) Muscles in the hair follicles, (C) Muscles that act at the elbow joint, (D) Muscles in the gastrointestinal (GI) tract
Answer is D. Smooth muscles in the gastrointestinal (GI) tract are innervated by both parasympathetic and sympathetic nerves. Smooth muscles in the wall of the blood vessels and arrector pili muscles in hair follicles are innervated only by sympathetic nerves. Muscles act at the elbow joint and muscles enclosed by epimysium are skeletal muscles that are innervated by somatic motor (general somatic efferent ) nerves.