Originally Posted by Seetal
it is invaginated because with the NTs ACh, the muscarinic receptors at the NMJ are triggered n this causes release of Ca2+ to cause muscle contractions. without a stimulation n also with depletion of ATP, muscle contractions do not occur. which is y in myasthenia gravis, where the ACh receptors are blocked by autoantibodies, the muscles become paralyzed.
i understand what you explain but my question is since t tubule is simply a invagination of plasma membrane and neuromuscular at plasma membrane is already in contact with terminal cisternae as it is located just under it why we need an invagination into muscle fibre. unless cisternae are present in middle of muscle fibre too?????