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 — Carries information IN to the CNS from receptors in the body.

Efferent (motor)

Carries information OUT of the CNS to effectors in the body.

Somatic Nervous System

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

Autonomic Nervous System

The division of the nervous system associated with involuntary control of muscles, as well as 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

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

Lower Motor Neuron

Has its cell body in the spinal cord and its axon in the spinal nerve, communicating with skeletal muscle fibers.

Neurotransmitter for Somatic Efferent Division

Acetylcholine (ACh)

Autonomic Efferent Nervous System

Controls involuntary functions via sympathetic and parasympathetic divisions, using three neurons between the brain and effector.

Effectors of Autonomic Nervous System

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

Pre-ganglionic Neuron

Neuron #2: Has its cell body in the CNS, a myelinated axon extending into the PNS, and synapses in an autonomic ganglion, releasing acetylcholine (ACh).

Post-ganglionic Neuron

Neuron #3: Has its cell body in the PNS (autonomic ganglion), an unmyelinated axon extending to the effector organ, and synapses on the effector, releasing acetylcholine (ACh) or norepinephrine (NE).

Sympathetic Nervous System

Prepares the body for acute/stress responses; "Fight or Flight" system. Exits from CNS are Thoracic and Lumbar, Ganglion is Close to CNS

Parasympathetic Nervous System

Prepares the body for restful situations; "REST AND DIGEST" system. Exits from CNS are Cranial and Sacral, Ganglion is Far from CNS

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 the 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)

Noradrenaline (most)

Neurotransmitter released by Postganglionic neurons (Parasympathetic)

Acetylcholine

involuntary muscles/tissues

smooth, cardiac, glands, and adipose tissue