Which type of muscle is found in the walls of internal organs and works involuntarily?
A. Skeletal muscle
B. Cardiac muscle
C. Smooth muscle
D. Voluntary muscle
Answer (1)
Correct Answer: C. Smooth muscleSmooth muscle is an involuntary muscle located in the walls of internal organs such as the intestines, blood vessels, bladder, and uterus. It functions automatically under the autonomic nervous system, meaning it contracts without conscious control.Unlike skeletal muscle, which is voluntary and has a striated (striped) appearance, smooth muscle is non-striated and spindle-shaped. It contracts slowly and rhythmically to perform essential internal functions like:Moving food through the digestive tract (peristalsis)Regulating blood vessel diameter (helps control blood pressure)Contracting the uterus during childbirthAdjusting pupil size in response to lightIn contrast:Skeletal muscle: Voluntary, moves bonesCardiac muscle: Involuntary, striated, found only in the heartVoluntary muscle is another term for skeletal muscleSmooth muscle plays a vital role in many life-sustaining processes like digestion and circulation. Disorders such as asthma, IBS, and hypertension often involve problems with smooth muscle function.
