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Unformatted text preview: 1 How does the brain know where the impulse came from? Answer: It has a map! Voluntary Motor Responses Start in the Brain Upper motor neurons in the primary motor area fire Impulses descend to the appropriate level of the brain or spinal cord Cross-over will occur at some levelthe right brain controls the left side There is a synapse with a lower motor neuron The lower motor neuron carries the signal via a spinal or cranial nerve to the effector A response occurs 2 ALS Amyotrophic lateral sclerosis (ALS)--Lou Gehrig's disease--is a progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord. As motor neurons degenerate, they no longer send impulses to muscles. Early symptoms include increasing muscle weakness, especially involving the arms and legs, speech, swallowing or breathing. Muscles begin to atrophy (become smaller). Limbs begin to look "thinner" as muscle tissue atrophies. Parkinson Disease Progressive disorder of the central nervous system Progressive disorder of the central nervous system Progressive disorder of the central nervous system Risk increases with age, uncommon before 30 yrs old Affects ~1 million Americans Risk factors = age, genetics, environmental toxin (?) Symptoms = tremors, rigidity, slowness of movement, impaired balance and coordination Cause = loss of dopamine (inhibitory neurotransmitter)...
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This note was uploaded on 04/17/2008 for the course BIO 1004.212.0 taught by Professor Douglasmerrill during the Winter '07 term at RIT.
- Winter '07