Biological school

The nervous system 

it start with an individual nerve cell called the Neuron.

how does the neuron fire?
resting potential 
slightly negative charge.
reach the threshold when enough neurotransmitter reach dendritesit's an electrochemical process. 
electrical inside the neuron 
chemical outside of the neuron ( in the synapse in the form of a neurotransmitter )
the firing is call action potential
The all of none response
the idea that either the Neuron fires or it does not no part way firing like a gun
Neurons communicate 
tiny junction
NEUROTRANSMITTERS
chemical messenger released by terminal button through the synapse
- 4 types of neurotransmitters

•  Acetylcholine  
• deal with motor movement and memory
• lack of dopamine has been linked to Parkinson's disease
• too much has been linked to schizophrenia

• serotonin
• involved in the mood control
• lack of serotonin has been linked to clinical depression.

• Endorphins
• involve in pain control
• many of our most addictive drugs deal with endorphins
• drug can be...
• agonist-make neuron fire
• antagonists-stop neural firing.

• Sensory Neurons (afferent Neurons)
• take information from the sense to the brain.

• Inter Neurons
• take message from sensory neutrons to other part of the brain or to motor Neutrons

• Motor Neurons (efferent Neurons)
• Take information from the brain to the rest of the body.

• Central Nervous system
• the brain and the spinal cord.
• Peripheral Nervous system.
• all nerves that are not encased in the bone.
• everything but the brain and spinal cord
• divided into two categories somatic and autonomic

• Somatic Nervous System
• control voluntary muscle movement 
• uses motor (efferent ) neurons.

• Autonomic Nervous system
• control the automatic function of the body

• divide into two categories the sympathetic and parasympathetic 

• Sympathetic Nervous system.
• fight or plight response.
• Automatically accelerates heart rate. breathing, dilates pupils slow down digestion.