Divisions of the Nervous System

Flashcards about the divisions of the nervous system, somatic efferent division, autonomic efferent nervous system, sympathetic and parasympathetic nervous systems.

Afferent (sensory)

Ascending — info IN to the CNS from receptors

Efferent (motor)

info OUT of the CNS to effectors

Somatic Nervous System

division of the nervous system to do with voluntary control of skeletal muscles and sensory information we are aware of.

Autonomic Nervous System

division of nervous system to do with involuntary control of muscles and sensory information we are not aware of.

Somatic Efferent Division

Controls voluntary muscle movements using two neurons between the brain and effector: an upper and a lower motor neuron.

Upper Motor Neuron

cell body in the brain and axon in the spinal cord.

Lower Motor Neuron

cell body in the spinal cord and axon in the spinal nerves — synapses with skeletal muscle fibers.

Neurotransmitter for Somatic Efferent Division

Acetylcholine (ACh)

Autonomic Efferent Nervous System

controls involuntary functions and has sympathetic and parasympathetic divisions, using two neurons between the CNS and effector.

Effectors of Autonomic Nervous System

Smooth muscle, cardiac muscle, glands, and adipose (fat) tissue

Sympathetic Nervous System

fight or flight — postganglionic neuron releases Ne

Parasympathetic Nervous System

rest and digest — postganglionic neuron releases Ach

Sympathetic Chain Ganglia

Located on either side of the vertebral column, where preganglionic axons synapse onto postganglionic neurons.

Location of Preganglionic Neuron Cell Bodies (Sympathetic)

Thoracolumbar levels of spinal cord (T1 to L2)

Location of Preganglionic Neuron Cell Bodies (Parasympathetic)

Cranial (brainstem) and sacral (spinal cord) levels

Neurotransmitter released by Postganglionic neurons (Sympathetic)

Norepinephrine (most)

Neurotransmitter released by Postganglionic neurons (Parasympathetic)

Acetylcholine

upper and lower motor neuron axons

both myelinated

autonomic preganglionic neuron cell body

located in CNS

autonomic preganglionic neuron axon

myelinated, extends in PNS to autonomic ganglion

autonomic preganglionic neurotransmitter

Acetylcholine

autonomic postganglionic neuron cell body

in autonomic ganglion

autonomic postganglionic neuron axon

unmyelinated, extends from PNS to effector

autonomic postganglionic neurotransmitter

acetylcholine OR norepinephrine

sympathetic nervous system axon lengths

preganglionic short, postganglionic long allows for widespread and coordinated esponse

parasympathetic nervous system axon lengths

preganglionic long, postganglionic short allows for focused response

parasympathetic chain ganglia

located near effector organs

location of postganglionic cell bodies

sympathetic chain/collateral ganglion or parasympathetic ganglion close to effectors