Skeletal system Flashcards
Functions
movement, maintenance of posture, respiration, heat generation, communication, constriction of organs and blood vessels, and pumping blood
What are the four characteristics that all muscle cells share?
Excitability, elasticity, contractibility, and extendability
Contractility
when a muscle cell forcibly contracts or draws in another part. Muscles can only pull. never push
Excitability
ability to respond to a stimulus
Extensibility
extender muscles must extend to allow flection
Elasticity
the ability to recoil or bounce back
what are the three types of muscles in the body?
Skeletal, cardiac, and smooth
Characteristics of skeletal muscle
Known as voluntary muscle, striated, many nuclei in each skeletal muscle cell. The nuclei are squished in the cell because of how many contractile proteins there are
Smooth muscle
Found in the walls of hollow organs, tubes, and other places like in our eyes. Involuntary, sometimes known as visceral muscle because it is associated with the visceral organs. Non-striated
Cardiac muscle
Only found in the heart, it is striated like skeletal muscle but is it involuntary. Autorhythmic
Autorhythmic
capable of contracting spontaneously WITHOUT nervous or hormonal signaling.
Muscles anatomy
Myofibrils -> muscle fiber (mitochondria, multiple nuclei, and sarcolemma[cell membrane]) -> Fascicles (bundles of muscle fibers) -> muscle.
Bundles of bundles of bundles
Supportive sheathes of connective tissue
Three- Outer: Epimysium
Middle: perimysium
Inner: Endomysium
Myofibrils
divided into little segments called sarcomeres. Within these sarcomeres are two myofilaments called actin and myosin
Actin
light, twisty filaments in the sarcomere. Contracts and brings the z-line in closer. Blocked by tropomyosin protein at rest
