Muscle Tissue
Advanced companion to Meet the Tissue Team, sung directly about muscle tissue: the sliding filament mechanism of actin and myosin, and the three real muscle types, skeletal (voluntary, striated, attached to bone), cardiac (involuntary, striated, found only in the heart, linked by intercalated discs), and smooth (involuntary, non-striated, lining internal organs). Structured as an escalating count from two filaments to three tissue types.
One filament called actin, thin and light, anchored at each end, A second filament called myosin, thick, with tiny heads that reach and pull, Two filaments sliding past each other and a sarcomere shortens, that's one contraction, Three kinds of muscle tissue built from this same sliding trick, each one different.
Type one is skeletal, striped with visible bands, voluntary, moved on command, attached to bone by tendon, Type two is cardiac, striped as well, but involuntary, found only in the walls of your heart, Type three is smooth, no stripes at all, involuntary, lining your intestines and your blood vessels, Three types, one sliding mechanism, each built for a different kind of work.
Cardiac cells link through intercalated discs, so one signal fires a thousand cells at once, Smooth muscle cells squeeze slow and steady, pushing food along your gut for hours, Skeletal muscle fires fast, a single spark and a whole fiber contracts within a heartbeat, Every contraction spends ATP, myosin heads letting go and grabbing on again, over and over.
Count the filaments, two, count the muscle types, three, count the beats a heart repeats, billions across a lifetime, I'm muscle tissue, actin and myosin sliding since the day you were born until the day you stop, One sliding motion, three different jobs, moving your arm, pumping your blood, squeezing your food along, Muscle tissue counts every beat, every step, every breath your body takes.
Advanced companion to: Meet the Tissue Team (Musco), sung about the real histology directly rather than through character persona.
Key Concepts: Muscle contraction works through the sliding filament mechanism: thin actin filaments and thick myosin filaments slide past each other, shortening the sarcomere, powered by ATP | There are three real types of muscle tissue: skeletal (voluntary, striated, attached to bone by tendon), cardiac (involuntary, striated, found only in the heart, cells linked by intercalated discs for synchronized contraction), and smooth (involuntary, non-striated, lining internal organs and blood vessels)
Key Words: actin, myosin, sarcomere, sliding filament, skeletal muscle, cardiac muscle, smooth muscle, intercalated disc