Tuesday - three hours of george t. Flashcards
What do ryanidine receptors do?
Release calcium from the sarcoplasmic reticulum.
Calcium induced calcium release (more of this goes on in cardiac muscle)
What causes the change of myosin to a 90 degree angle (cocking the head)?
What causes a powerstroke in muscle?
What causes the dislocation of myosin from actin?
Cleavage of ATP to ADP and phosphate.
Release of the phosphate from the ADP/phosphate complex (which is followed by release of the ADP itself)
ATP binding to myosin
Lambert-eaton syndrome
Tx?
caused by autoantibodies against calcium channels in motor neurons resulting in an inability to release acetylcholine.
Diaminopyridine, blocks K channels to lengthen A.P.
Disease that involves degeneration of motor neurons?
Amyotropic lateral sclerosis (lou gehrig’s disease)
What disease uses antibodies to attack nicotinic receptors in skeletal muscle?
Myasthenia gravis.
How can anesthetics cause malignant hyperthermia
if ryanodine receptor is mutated, it can release excessive amounts of calcium triggered by anesthetics.
What causes duchenne’s
mutation in dystrophin, a skeletal muscle support protein
What type of contracture happens when you cannot move a load?
Isometric contraction
Type 1 fibers vs Type 2
Type 1 - slower. in distance runners, postural muscles. Red fibers (lots of myoglobin). Aerobic (need lots of O2)
Type 2 - fast twitch. extraocular muscles of eye. myosin ATPase is faster. White fibers. Anerobic metabolism.
Concentric vs eccentric contractions
concentric - contracts while shortening
eccentric - muscle lengthens while attempting to shorten (running down hill)
Force generation in a muscle cell is dependent on what?
Speed of muscle contraction is dependent on what?
Number of actin-myosin crossbridges formed per cross-sectional area
Speed of muscle contraction is dependent on myosin ATPase activity
Myasthenia gravis
Autoantibodies attack nicotinic receptors in skeletal muscle (make is so Ach cannot bind)
