autonomic nervous system

splanchnic nerves

"gut nerves" leads away from body ganglia to the digestive tract (into the body cavity)

neurotransmitter released by sympathetic

(ACh from a few sympathetic postganglionic axons) NE (norepinephrine) from most sympathetic postganglionic axons

somatic vs autonomic nervous system

*Somatic* (control voluntary movement ex. Moving your finger) vs. *autonomic nervous system* (relates to hearts and glands and makes up sympathetic and parasympathetic nervous system)

motor neuron #2 in ANS

-a ganglion -post-ganglionic or second-order neuron -unmyelinated (grey in fresh state)

motor neruon #1 in ANS

-begins in intermediolateral horn of the the spinal cord or in the corresponding areas of the brain -is a pre-ganglionic or first-order neuron -myelinated (white in fresh state)

Parasympathetic Component of Glossopharyngeal Nerve (CN IX)

-increased salivation (in the parotid gland)

lens shape for distant vision

-lens flattened -suspensory ligaments taut -ciliary muscles relaxed

lens shape for near vision (accomadation)

-lens thickened, more spherical -suspensory ligaments relaxed -ciliary muscles contract, moving ciliary body closer to the lens

target of the autonomic nervous system (effector organs)

-smooth muscle -cardiac muscle -glands

Why do some postsynaptic sympathetics travel in spinal nerves and others travel in splanchnic nerves?

1) *spinal nerves:* ---->Generally, sympathetic nerves have *short* pre-ganglionic motor neurons that synapse in the sympathetic chain ganglia (spinal nerve) so the postganglinic neurons are relatively *long* (body wall) 2) *splanchnic nerves*: ---->Reverse is true in the gut ---->Long pre-ganglionic neurons that DO NOT synapse in the sympathetic chain ganglia (spinal nerve) ---->They use the pre-vertebral ganglia that forms the splanchnic nerves (body cavity)

what 4 cranial nerves are part of the parasympathetic nervous system?

1) CN III (oculomotor) 2) CN VII (facial) 3) CN IX (glossophayngeal) 4) CN X (vagus)

Parasympathetic Component of Oculomotor Nerve (CNIII)

1) innervates the spincter pupilllae which causes pupillary constriction (bright light) 2) lens shape for near vision (accomodation) --->ciliary muscles contract, moving closer to lens

How is the fight or flight response activated?

1) presynaptic sympathetic neuron innervates the adrenal medula (acetyle CoA) 2)releases epinerpherine and norepinepherine into the blood stream 3)activates all activity at once

The two motor neurons in ANS pathways

1. Has cell body in CNS - its myelinated axon extends from the CNS to an autonomic ganglion 2. Has its cell body in the same autonomic ganglion - its unmyelinated axon extends directly from the ganglion to the effector (smooth muscle, cardiac muscle, or a gland)

what neurotransmitter is released by parasympathetic autonomic nervous system?

ACh from all preganglionic axons and parasympathetic postganglionic axons

Parasympathetic Component of Facial Nerve (CN VII)

Cause lacrimation (tears), mucus productions and salivation

Parasympathetic Component of Vagus Nerve (CN X)

Causes bronchial constriction, increase in heart rate and increase action of digestive system

origin of the parasympathetic division

Craniosacral origin or CNS (Brain S2,3,4) --->preganglionic neurons located in brainstem nuclei and S2-S4 regions of the spinal cord

sympathetic target reactions

Eyes: pupils dilated, far sight, lens flattened (cilliary muscles) Lacrimation: decrease (parotid gland decrease) digestive system: decrease heart rate: increase bronchi: dilate

How do sympathetic post-ganglionic neurons supply the head, neck, and lower extremities?

Hitch a ride on the arteries

ANTAGONISM OF THE SYMPATHETIC AND PARASYMPATHETIC NERVOUS SYSTEMS

Most effector organs receive dual innervation, but some (e.g., adrenal medulla, sweat glands, pilomotor muscles, and many blood vessels) are innervated by only the sympathetic nervous system. --->opposite effects by each divsion

origin of the sympathetic (thoracolumbar) division

Preganglionic neurons located in lateral horns of T1-L2 regions of spinal cord (no cranial nerves)

what part of the spine contains presynaptic neurons for sympathetic?

T1-L2 region of spinal cord

spinal nerves go where?

The body wall, which includes the thoracic wall, abdominal wall, and extremeites

Why is the sympathetic division also called the thoracolumbar division?

The presynaptic neurons have their cell bodies within the lateral horns of the *T1-L2 spinal cord*

sympathetic chain ganglia

a series (or chain) of connected sympathetic postganglionic cell body clusters positioned along each side of the vertebral column adjacent to the major body wall branches of the aorta. --->extends up into the neck and down into the pelvis

What neurotransmitter is released by somatic motor neurons?

acetylcholine into skeletal muscle

sympathetic ganglia include?

chain (paravertebral) ganglia, cervical ganglia, and collateral (prevertebral) ganglia

Functions of the parasympathetic nervous system

constricts pupils, stimulates flow of saliva, constricts bronchi, slows heartbeat, stimulates peristalsis and secretion, stimulates bile release, contracts bladder • heart-rate decreases • bronchioles constrict • digestion increases • salivation increases • lacrimation increases

parasympathetic S2-S4 spinal cord component

finish parasympathetics to pelvis, takes over from vagus nerve (genatia, bladder, rectum and descending colon)

post-ganglionic autonomic cell bodies

forms ganglia in the periphery

sympathetic trunk

function: allows for preganglionic and ganglonic nerves fibers to communicate with each other

two motor neurons

going from CNS to target (a presynaptic and postsynaptic neuron).

SNS (somatic nervous system) causes only excitation of target; whereas ANS can cause excitation or?

inhibition

Except in the head, parasympathetic neuron synapses occur within?

intramural ganglia (in the wall of the organ innervated)

somatic motor neurons

nerve cells whose cell bodies are in the brainstem and spinal cord that serve skeletal muscles

rest and digest

parasympathetic ("the pear made me cry")

ganglia are close to the target organs in which division of the ANS?

parasympathetic (presynaptic neurons are relatively long and postsynaptic neurons are relatively short)

What are the two divisions of the autonomic nervous system?

parasympathetic and sympathetic

Pelvic splanchnics (S2-4)

parasympathetic pre-ganglionic motor neurons in spinal cord are sometimes called "nervi errigentes" because they control erection

target of somatic motor system (effector organs)

skeletal muscle

Control of the throat in digestion is?

somatic

fight or flight

sympathetic

thoracolumbar

sympathetic

Why do blood vessels only have sympathetic nerve supply?

sympathetic activation constricts arteries

Ganglia are close to the spinal cord in which division of the ANS?

sympathetics (presynaptic sympathetic neurons are relatively short and the post synaptic neurons are relatively long)

Where do presynaptic sympathetic neurons travel?

the chain of ganglia

craniosacral division

the parasympathetic nervous system, in which nerves originate in the brain stem or sacral region of the spinal cord

Why is the parasympathetic division sometimes referred to as the craniosacral divsion?

the presynaptic neurons have their cell bodies within nuclei in the brainstem (cranio) or lateral horns of the *S2-S4* spinal cord (sacral)

In the sex organs (in contrast to elsewhere in the body the two divisions antagonizing one another) what do they divisons do?

they compliment one another (sexual arousal=PsNS and orgasm=SNS)

The Autonomic Nervous System Controls:

• Cardiac muscle (myocardium). • Smooth Muscle (digestive tract, bronchi, blood vessels). • Glands (salivary, digestive, lacrimal, sweat and sex glands)

Functions of the sympathetic nervous system

• heart-rate increases • bronchioles dilate • digestion decreases • salivation decreases • lacrimation decreases • sweating increases