peripheral nervous system

somatic motor pathways

innervate skeletal muscles; voluntary actions

how many neurons in a somatic motor pathway?

single neuron

• cell body of neuron in spinal cord or brain

• single long axon to muscle

divisions of the visceral motor/autonomic system

parasympathetic division

sympathetic division

enteric division

parasympathetic division

rest and digest

sympathetic division

action (fight or flight)

enteric division

digestive reflexes

how many neurons are in peripheral parasympathetic and sympathetic pathways?

two neurons

synapse in autonomic ganglion

preganglionic and postganglionic

preganglionic neuron: myelinated or not myelinated?

myelinated

what does the preganglionic neuron release?

acetylcholine

postganglionic neuron: myelinated or not myelinated?

not myelinated

what does the postganglionic neuron release?

acetylcholine or norepinephrine depending on pathway

parasympathetic targets and responses: eye

constriction of pupil

parasympathetic targets and responses: salivary glands

secretion of saliva

parasympathetic targets and responses: heart

decrease in heart rate

parasympathetic targets and responses: airways

constriction

parasympathetic targets and responses: digestive system

increased activity

parasympathetic targets and responses: urinary bladder

urination

parasympathetic targets and responses: lacrimal glands

secretion of tears

sympathetic targets and responses: eye

dilation of pupil

sympathetic targets and responses: salivary glands

inhibition of salivation

sympathetic targets and responses: heart

increase in heart rate and force of contraction

sympathetic targets and responses: airways

dilation

sympathetic targets and responses: digestive system

decreased activity

sympathetic targets and responses: urinary bladder

inhibition of urination

what else does the sympathetic target?

vasodilation and vasoconstriction

activity of sweat glands

arrector pili muscle (goose bumps)

where do parasympathetic pathways leave from CNS?

leave CNS from brainstem or along sacral spinal nerves

where do parasympathetic pathways synapse in autonomic ganglion?

near or in effector

what do parasympathetic pathways release?

release primarily acetylcholine from postganglionic neuron to target

where do sympathetic pathways leave from CNS?

leave CNS along thoracic or lumbar spinal nerves

where do sympathetic pathways synapse in autonomic ganglion?

synapse in autonomic ganglia near vertebral column

• chain ganglia

• collateral ganglia

what do sympathetic pathways release?

primarily release norepinephrine to targets

• acetylcholine released to sweat glands

where do parasympathetic pathways travel through?

travel through cranial nerves

• about 90% through vagus nerves

• also through oculomotor, facial, and glossopharyngeal nerves

travel through sacral spinal nerves

where do parasympathetic pathways also travel through?

many pathways travel through autonomic nerve plexuses

ex: cardiac plexus, celiac plexus, pelvic plexus

adrenal medulla

inner part of adrenal gland; modified sympathetic ganglion

what do the postganglionic cells in the adrenal medulla release?

primarily adrenaline/epinephrine

smaller amounts of noradrenaline/norepinephrine

what is another function of the adrenal medulla?

boosts and extends some sympathetic responses

enteric nervous system

regulates digestive reflexes

myenteric plexus

submucosal plexus

myenteric plexus

regulates smooth muscle of digestive tract

submucosal plexus

regulates secretion; monitors chemical environment

parts of the somatic system

cervical/brachial plexus

brachial plexus

intercostal nerves

lumbar plexus

sacral plexus

nerve in the cervical/brachial plexus

phrenic nerve

what does the phrenic nerve innervate?

innervates diaphragm

nerves in the brachial plexus

musculocutaneus, axillary, median, radial, ulnar nerves

what doe musculocutaneus, axillary, median, radial, ulnar nerves innervate?

innervate arm

intercostal nerves

innervate trunk

nerve in the lumbar plexus

femoral nerve

what does the femoral nerve innervate?

innervates anterior part of leg

nerve in the sacral plexus

sciatic nerve

what does the sciatic nerve innervate?

innervates posterior part of leg