Final answer:
Neurodegenerative disorders like Alzheimer's and Parkinson's disease involve the loss of nervous system functioning due to neuronal death. Key factors in Alzheimer's disease include beta-amyloid plaques and neurofibrillary tangles. Alpha-synuclein protein is linked to Parkinson's disease.
Step-by-step explanation:
Neurodegenerative disorders like Alzheimer's and Parkinson's disease are illnesses characterized by a loss of nervous system functioning caused by neuronal death. One key factor in Alzheimer's disease is the accumulation of beta-amyloid plaques, while Parkinson's disease is linked to an increase in a protein called alpha-synuclein. These abnormal changes in the brain, including the development of amyloid plaques and neurofibrillary tangles, are associated with the loss of synapses between neurons and ultimately the death of neurons.