Myasthenia gravis is a rare autoimmune disease. It causes weak muscles and tiredness. Stress and hot weather can make the symptoms worse. It is treated with acetylcholinesterase inhibitors or immunosuppressants.
Images for kids
Neuromuscular junction: 1. Axon 2. Muscle cell membrane 3. Synaptic vesicle 4. Nicotinic acetylcholine receptor 5. Mitochondrion
A juvenile thymus shrinks with age.
The nicotinic acetylcholine receptor
Photograph of a patient showing right partial ptosis (left picture), the left lid shows compensatory pseudo lid retraction because of equal innervation of the levator palpabrae superioris (Hering's law of equal innervation): Right picture: after an edrophonium test, note the improvement in ptosis.