Nervous System Flashcards
Central nervous system (CNS)
– consists of the brain and spinal cord.
Peripheral nervous system (PNS)
– consists of all the nerves originating at the brain and spinal cord and branching out to other parts of the body.
Branches of the peripheral nervous system:
Somatic nervous system (SNS)
Autonomic nervous system (ANS)
Somatic nervous system (SNS)
– nerves innervate the skin and skeletal muscle; usually associated with conscious activity.
In control
Autonomic nervous system (ANS)
– nerves innervate the viscera; associated with unconscious activities.
No control
Branches of the autonomic nervous system:
Sympathetic nervous system
Parasympathetic nervous system
Sympathetic nervous system
- speed up heart rate
actions ready the body expend energy; secrete the neurotransmitter norepinephrine.
Inc. heart rate
- epinephrine/ norepinephrine
o makes it easier to depolarize
o results in increase heart rate
Parasympathetic nervous system
- slow down heart rate
most active under resting conditions; may counterbalance sympathetic nervous system actions to restore resting conditions.
Dec. heart rate
- normal resting conditions
- rate of impulses indicates strength of impulse (faster impulse = stronger reaction; slower impulse = weaker reaction)
- Acetylcholine is released every time an impulse is released
o makes it harder for heart to depolarize (contract)
o heart rate is lower & slower ( resting conditions)
