What part of the neuromuscular junction is affected in myasthenia gravis?
What part of the neuromuscular junction is affected in myasthenia gravis?
MG is an autoimmune disorder affecting the neuromuscular junction characterized by a T-cell–mediated response targeting the postsynaptic acetylcholine receptor or receptor-associated proteins.
Where are junctional folds found?
The first specialization at the motor end plate is the presence of junctional folds, which are deep invaginations or grooves of the sarcolemma that provide a large surface area where the ACh from the synaptic end bulb can interact.
What is myasthenia gravis Medscape?
Myasthenia gravis (MG) is a relatively rare autoimmune disorder in which antibodies form against nicotinic acetylcholine (ACh) postsynaptic receptors at the neuromuscular junction (NMJ) of the skeletal muscles. It is a type-II hypersensitivity immune response.
Which part of the neuromuscular junction is affected in curare poisoning?
Curare affects the stimulus (the EPSP) which normally leads to the initiation of the muscle action potential. An animal that is poisoned with curare will asphyxiate because the process of neuromuscular transmission at respiratory muscles is blocked. Normally, the magnitude of the endplate potential is quite large.
What is the sarcolemma?
Sarcolemma. The sarcolemma or cell membrane is the site where calcium enters and leaves the cell through a distribution of ion channels, transporters, and pumps. The T-tubules are invaginations of the sarcolemma that form a permeability barrier between the cytosol and the extracellular space (Brette and Orchard, 2003).
Where is the sarcolemma?
muscle cell
The sarcolemma is the plasma membrane of the muscle cell and is surrounded by basement membrane and endomysial connective tissue. The sarcolemma is an excitable membrane and shares many properties with the neuronal cell membrane.
What is the indented region of the sarcolemma?
Sarcoplasmic reticulum and T tubules There are two sets of tubules within skeletal muscles fibers that carry out critical functions during muscle contractions: the sarcoplasmic reticulum and the T tubules. T tubules (transverse tubules) are invaginations, or indentations of the sarcolemma.
Which is the first line drug of myasthenia gravis?
(See “Chronic immunosuppressive therapy for myasthenia gravis”, section on ‘MuSK-positive MG’.) Children — As with adults, the treatment of children with MG should be individualized based on the severity and pace of the disease [39,40,61]. Pyridostigmine is the first line of therapy (see ‘Dose and titration’ above).
How does curare interfere with the neuromuscular junction?
Curare acts as a neuromuscular blocking agent by binding to the acetylcholine receptor (AChR) at the neuromuscular junction and preventing nerve impulses from activating skeletal muscles (Bowman, 2006). However, it is not known if curare has a gender-specific effect on physical activity and whole body metabolic rate.
What connects the sarcolemma?
The two major structural complexes involved in the connections between sarcomeric proteins and the extracellular matrix include the membrane-spanning integrin complex and the dystrophin complex. Myosin.
