| A | B |
|---|
| Functions of muscles | Movement, stability, control of body openings and passages, heat production, glycemic control |
| 3 types of muscle tissue | skeletal, cardiac, smooth |
| Skeletal | multi-nucleated, voluntary, striated, example biceps, triceps |
| Cardiac | bronze, single nucleated, involuntary; example heart |
| smooth | fusiform shaped, single nucleated, involuntary; example lining of stomach |
| excitability | responds to chemical signals, stretch and chemical signals across the plasma membrane |
| conductivity | local electrical charnge triggers a wave of excitation that travels along the muscle fiber |
| contractility | shortens when stimulated |
| extensibility | capable of being stretched |
| elasticity | returns to its original rest length after being stretched |
| tendons | connect muscle to the bone |
| muscle fibers are made of | fascicles |
| epimysium | surrounds the entire muscle |
| perimysium | wraps muscle fibers together in bundles called facsicles |
| endomysium | covers muscle fibers |
| muscle fibers means | muscle cells |
| sarcolema | the plasma mebrane of the muscle cell |
| fascia | separates neighboring muscle or muscle groups from each other |
| sarcoplasm | the cytoplasma of the muscle cell |
| myofilaments | proteins that help us contract our muscles; most important in the muscle cell |
| 3 types of myofilamenst | thin, thick and elastic |
| thick myofilament | made up of protein called myosin |
| thin myofilament | made up of a protein called actin and tropomyosin |
| tropomysin | has troponin bound to it |
| contractile proteins, myosin and actin | do the work of contraction |
| tropomyosin and troponin are | regulatory proteins; act like a switch can/cannot contract |
| contractions are activated by | release of calcium into the sarcoplasm and its binding to troponin |
| when troponin is bound by calcium | it changes shape and moves tropmyosin off the active sites on actin |
| elastic filaments | made of springy protein called titin |
| titin | stablilizes the thick filament,, centers it between thin filament, prevents over stretching and recoils like a spring |
| striations result from the precoise organization of | myosin and actin in cardiac and skeletal muscle cells |
| striations are alternating | A-bands (dark) and I-bands (light) |
| motor unit | one nerve fiber and all muscle fibers innervated by it |
| synaptic knob | swollen end of nerve fiber, contains synaptic vesicles and acetylcholine (ACh) |
| synaptic cleft | gap between synaptic knob and sarcolemma |
| schwann cell | envelops and isolates neuromuscular junction (NMJ) |
| cardiac and smooth muscle share these properties | cells are myocytes, both involuntary, innervation is from the autonomic nervous system ( not from the somatic motor neurons) |
| 2 types of smooth muscle | single unit and multi unit |
| multiunit smooth muscle | found in largest arteries and air passages, pilorector muscles and iris of the eye |
| single unit smooth muscle (also called visceral muscle) | blood vessels, digestive, respiratory, urinary and reproductive tracts |
| gap junctions | electrically couple myocytes to each other in smooth muscle |
