Unit IV: Biological School: The Nervous System:

Biological School:
The Nervous System:
Neuron-individual nerve cell
How does a Neuron Fire?:
Resting Potential: slightly negative charge
Reach the threshold when enough neurotransmitters reach dendrites
Go into Action Potential (firing)
All or None Response: the idea that either the neuron fires or it does not - no part way firing

Neurotransmitter: chemical messengers released by terminal buttons through the synapse.
Acetylcholine: ACH : deals with motor movement and memory. Lack of ACH has a link to Alzheimer's disease
Dopamine: deals with motor movement and alertness. Lack of dopamine has been linked to Parkinson's disease. Too much has been linked to schizophrenia
Serotonin: involved in mood control. Lack of serotonin has been linked to clinical depression.
Endorphins: involved in pain control. Many of our most addictive drugs deal with endorphins.
Norepinephrine: helps control alertness and arousal. An under supply can lead to depression. An oversupply can lead to manic symptoms.
GABA(gamma-aminobutyric acid): major inhibitory neurotransmitters. An under supply can lead to seizures.
Glutamate: major excitatory neurotransmitter; involved in memory. Oversupply can overstimulate the brain leading to migraines

Drugs can be ...
Agonists: make neuron fire
Antagonists: stop neural firing
Reputable Inhibitors: block transmitters from entering the neuron.
Three Types of Neurons:
1. Sensory Neurons(afferent Neurons): take information from the senses to the brain
2. Inter Neurons: take messages from sensory neurons to other parts of the brain or to motor neurons.
3. Motor Neurons(Efferent Neurons): take information from brain to the rest of the body

Reflexes: normally sensory(afferent) neurons take info up through the spine to the brain.