In: Anatomy and Physiology
Week 4 lab A& P the muscular system
7. T or F The influx of sodium ions generates an action potential at the motor end plate
8. A ____ consist of a motor nerve fiber and all the muscle fibers it stimulates at neuromuscular junctions.
9. What is ACh? Explain what it is and it's function during the sequence of events at the neuromuscular junction.
18. The extensor digitorum longus muscle is located in the ___ compatment of the leg.
19. The suprahyoid muscles connect the hyoid bone to the ___.
20. The ____ muscles perform voluntary eye movements.
Q7_True-influx of sodium ions generate action potential at the motor end plate.It is the point where muscle comes in contact witth motor nerve.Since nerve is stimulated and carries it towards muscle,when reached at the end plate It transfers the stimuli causing sodium ion influx and hence depolarisation of muscle membrane_action potential wave is created if the stimuli is above the threshold potential.
Q8_A single efferent neuron can supply multiple muscle fibres_The efferent neuron along with all the muscle fibre it supply at neuromuscular junction together forms a MOTOR UNIT.They work in a cocordinated manner for contraction of muscles.Thus diesignated as a unit.
Q9_ACh_acetyl choline_It is a neurotransmitter released from nerve terminals of somatic and parasympathetic nerves_it has excitatoryaction.Acts on binding with specific cholinergic receptors at neuromuscular junction called nicotinic cholinergic receptors(Nm),but has no intrinsic activity.Series of events are_a_Impulse is conducted to the nerve terminals_b_it releases ACh from synaptic vesicles in the synapse_c_Ach binds with Nm receptors in the neuromuscular junction or motor end plate._d_opening of Na+ channel._e_influx of Na into the cells_f_production of depolarising wave /action potential._g_like wise the wave of depolarisation is conducted through the membrane and produces contraction_h_termination of Ach action by local degredation by enzyme acetylcholine esterase..
Q18_Extensor digitorum longus is a flexor muscle present in anterior compartment of leg and dorsum of foot.It originates from latral condyle of tibia,upper part of fibula and upper part of interosseus membrane.It divides into 4 tendons inorder to insert in lateral 4 toes.it is supplied by deep peroneal nerve Action is dorsiflexion of foot and extends metatarsophalangeal and interphalangeal joints of big toe.
Q20_Extraoccular muscles are responsible for voluntary eye movement.These are 6 sets of muscles _four recti_superior,inferior,medial and lateral recti_2obliques_superior and inferior oblique. Also levator palpebre superioris an eyelid muscle hepls in elevation of upper eye lid.Nerve supply is lateral rectus supplied by abducens nerve,superior oblique by trochlear nerve and all other musckes mentioned are suppled by occulomotor nerve.