Biology Education

Difference between Cardiac Muscle and Skeletal Muscle

  • Main Difference

    Our body contains three types of muscles, cardiac muscle, skeletal muscle and smooth muscle. Cardiac and skeletal muscles are two major types. The cardiac muscles are found in heart while skeletal muscles are linked on bones and cartilage. The main difference is the arrangement of cell in a tissue.

    Cardiac Muscle

    cardiac_muscleCardiac muscles are found on heart. They involuntary striated muscles. Cardiac muscles are made up of “y” shaped cells. It has long branched cells with two ovoid nuclei. It is striated muscle because it contains sarcomeres. The cardiac tissues are made up of multiple myofibrils containing sarcomere. The outer membrane is called Sarcolemma. Sarcolemma has T-tubules, which are invaginations extending from Sarcolemma and inside of cell. T- tubules are responsible to distribute action potential equally throughout the cell. It has intercalated cells containing desmosomes that connect one cell to the other. Cardiac muscles are involuntary as they pump blood around the body non-stop. It has numerous mitochondria to generate an ample of energy to pump blood.

    Skeletal Muscle

    skeletal-muscleSkeletal muscle also called striated muscle because of it striate appearance under the microscope. The main function of skeletal muscle is to move the skeleton. They are in direct control of the somatic nervous system. It is mostly innervated by voluntary motor nerves. Skeletal muscles are attached to bones by bundles of collagen called tendon. It can produce contraction, twitches and powerful sustained tension and return to its original shape. Individual cells called skeletal muscle cells are largest cells in human body. Each muscle fiber is consists of contractile unit called myofibrils. It appears striated with light and dark bands. These alternating bands are formed by contractile elements called actins and myosin filaments, repeated units are called sarcomeres. It also has two other important regulatory protein called troponin and tropomyosin, necessary for muscle contraction. The muscle fibers are long cylindrical and have numerous nuclei. There are many skeletal muscles some are bicep and triceps in for arm to flex and extend the forearm respectively. The skeletal muscle if used can increase in size and if disused can cause atrophy. Skeletal muscle gets exhausted easily.

    Key Differences

    • Cardiac muscles are found on heart while skeletal muscles are found all over the body attached to the bones and tendons
    • Morphologically cardiac muscles are striped with cross linkage while skeletal muscles are only striped.
    • Cardiac muscles are involuntary as they are innervated by somatic nervous system while skeletal muscles are voluntary as they are innervated by motor nerves.
    • Cardiac muscles are responsible to pump blood throughout the body while skeletal muscles are responsible for movement, twitching, holding and to perform work
    • Cardiac muscles have long tertranic contraction while skeletal muscles have small twitch and long tertranic contraction.
    • Cardiac muscles are elastic in nature while skeletal muscles are non elastic in nature.
    • Cardiac muscle diameter is 10 micro meter while skeletal muscle is 10 to 80 micro meter.
    • Cardiac muscle has one or two nuclei while skeletal muscles have multiple nuclei.
    • Cardiac muscles have intercalated disc while skeletal muscles do not have intercalated disc.
    • Cardiac muscles have intermediate speed of contraction while skeletal muscles contract fast.
    • Cardiac muscle never gets exhausted while skeletal muscles get exhausted.

    Video Explanation