Question

Which of the following is a fusiform muscle?
A. Cardiac muscle
B. Smooth muscle
C. Intercalated disc
D. All of these

Answer 1

Hint: Fusiform means having a spindle-like shape that is wide in the middle and tapers at both ends. It often implies a focal broadening of a structure that continues from one or both ends, such as an aneurysm on a blood vessel.

Complete step by step answer:
-There are three types of muscles. They are - cardiac muscle tissue, skeletal muscle tissue and smooth muscle tissue.
-Cardiac muscle tissue is only found in our heart, where it performs coordinated contractions that allow our heart to pump blood through our circulatory system.
-Cardiac muscle is composed of irregular branched cells bound together longitudinally by intercalated discs and shows strong, involuntary contractions.

                                                                 Fig: Different types of muscle cell

-Smooth muscle cells are fusiform in shape meaning that they are wide in the middle with tapered ends, they also have only a single nucleus.
-Smooth muscle cells are non striated because there is no regular arrangement of actin and myosin filaments. They are involuntary muscles.
-Intercalated discs are part of the cardiac muscle sarcolemma and they contain gap junctions and desmosomes.

So, the answer is B. Smooth muscle

Additional information:
-Skeletal muscle is a form of striated muscle tissue which is under the voluntary control of the somatic nervous system. Most skeletal muscles are attached to bones by bundles of collagen fibers known as tendons
-Contractions of the heart are controlled by specialized cardiac muscle cells called pacemaker cells that directly control heart rate.

Note:
-The gluteus maximus is the largest muscle in the human body.
-Stapedius is the smallest muscle of the human body.