Autoimmune disease Flashcards
Autoimmune disease is when…
the immune system attacks one or more self-antigens.
MG is…
Myasthenia gravis is an autoimmune disease that targets the neuromuscular junctions between motor neurons and skeletal muscle cells.
Motor neuron releases…
acetylcholine, a cell signalling molecule, into the small gaps between neurons and muscle fibres.
Acetylcholine binds with…
receptor protein on the surface membrane of the muscle fibres.
As the acetylcholine binds it stimulates…
channels to open allowing sodium ions to move through the membranes.
The influx of sodium ions begins…
a series of events that result in muscle contraction.
People with MG have a helper…
T cells that are specific for the protein receptors for acetylcholine.
T cells in MG stimulate a clone of…
B cells to differentiate into plasma cells and secrete antibodies that bind to the protein receptor, so blocking the transmission.
The muscle fibres absorb the receptor-
antibody complex and destroy it.
Without acetylcholine receptors, the muscle cells do not…
receive any stimulations, so the muscle tissue starts to break down.
Symptoms of MG:
- muscle weakness that gets worse after with activity and improves with rest
- muscles become fatigued very easily
Treatments of MG:
- a drug that inhibits the enzyme in synapses that breaks down acetylcholine
- surgical removal of the thymus glands
As the enzymes are inhibited, there will be higher…
concentration of acetylcholine in synapses, so it stimulates muscle fibres to contract for longer.
Other autoimmune diseases:
- multiple sclerosis
- diabetes type 1
- rheumatoid arthritis
