Comparison of Somatic and Autonomic Nervous System (lower motor neurons)

Ganglionic neurons have unmyelinated what?

Axons that are even smaller in diameter than preganglionic axons, so propagation of nerve signals are relatively slow in comparison to somatic motor axons

The cell body of a lower motor neurons lies where?

within the brainstem nucleus or the spinal cord and its axons exit the CNS in either a CRANIAL NERVE or a SPINAL NERVE and extends to a skeletal muscle

Lower motor neurons in the Somatic Nervous System

A SINGLE lower motor neuron extends from the CNS to skeletal muscle fibers

Lower motor neurons in the Autonomic Nervous System

A chain of 2 lower motor neurons extend from the CNS to innervate cardiac muscle, smooth muscle, and glands.

The motor neurons of the Somatic Nervous System are?

(1) composed of myelinated axons with a large diameter allowing for faster propagation of nerve signal (2) always release ACh neurotransmitter from its synaptic knobs to stimulate or EXCITE skeletal muscle fiber

The neurotransmitter released from the ganglionic neuron in response to a nerve signal is ?

Either ACh or Norepinephrine (NE). Both neurotransmitters can either excite or inhibit an effector depending on the type of receptors present within the effector

The second neuron in the ANS (pathway) is the?

Ganglionic Neuron

Preganglionic neuron

Its cell body lies within the brainstem nucleus or spinal cord. A PREGANGLIONIC AXON extends from this cell body and exits the CNS in either a cranial nerve or spinal nerve

Ganglionic neuron

Its cell body resides within and autonomic ganglion. A POSTGANGLIONIC AXON extends from the cell body to an effector (cardiac muscle, smooth muscle, or a gland)

Preganglionic neurons have myelinated what?

Myelinated axons that are typically small in diameter, and nerve signals always result in the release of ACh to excite the second neuron

The first of the 2 ANS motor neurons is the ?

Preganglionic neuron

Where does the Preganglionic axon project to?

To an AUTONOMIC GANGLION in the peripheral nervous system.

One significant anatomic difference between the somatic nervous system and autonomic nervous system is the ?

number of lower motor neurons that extend from the CNS