HA the autonomic nervous system

ANS

• efferent visceral motor

• Only modulate visceral reflexes

• smooth muscle

• Cardiac muscle

• Glands

• Adipose tissue

Effectors of ANS:

Motor side

Axons coming out on…

Parasympathetic

• resting and digesting

• Cranial-sacral (S2-S4 and cranial nerves III, VII, IX, X)

Controlling effector tissues

Sympathetic

• flight, fight, freeze, sex

• Thoracolumbar division (T1-L2)

Skin/adrenal either turned off/on

Two neuron chain

Both sympathetic and parasympathetic systems have a…

Way station

Both divisions have a “___ ___” for the first neuron to make connection at a ganglion

• preganglionic neuron

• Postganglionic neuron

ACh

Preganglionic cell releases ACh as neurotransmitter

All in CNS- but in different areas

Location of preganglionic cell bodies-

• lateral horns T1-L2 (sympathetic)

• Parasympathetic- sacral lateral horns and cranial nerve nuclei (III, VII, IX, X)

• synapse of preganglionic cell (location of “way station” ganglion) and length of preganglionic fiber

• Type of neurotransmitter used by second neuron on effectors

Differences of sympathetic and parasympathetic divisions

Spinal cord

Preganglionic cell is relatively short because it’s close to…

Myelinated

In CNS-

Never myelinated

Postganglionic-

Norepinephrine

Sympathetic Postganglionic neuron

Acetylcholine

Parasympathetic Postganglionic

Norepinephrine

Speeds up cardiac muscle contraction

Acetylcholine

Slows down cardiac muscle contraction

Norepinephrine

Stop salivary glands from secreting

Acetylcholine

Start and promote salivary glands to secrete saliva

Ganglia

Weigh station close to ___

Parasympathetic

Long preganglionic fiber; short Postganglionic fiber. Preganglionic fiber synapses on ganglia in head or terminal ganglia

Descending colon and rectum

Involuntary stimulation

Pelvic

Voluntary smooth muscle

CN III

Postganglionic fiber innervates ciliary body (pupil constriction)

Can VII

Postganglionic fiber innervates lacrimal gland (tears), submandibular and sublingual glands

CN IX

Postganglionic fibers terminate on parotid gland

CN X

Postganglionic fibers terminate on viscera

Sympathetic

Short preganglionic fiber; long Postganglionic fiber. Preganglionic fiber synapses on paravertebral (sympathetic ganglia) or on prevertebral ganglia

Both sides of spinal cord

Sympathetic motor division found on…

White matter

Myelinated tissue

Gray matter

Unmyelinated tissue

Adrenal medulla (secretes hormones, not neurons)

Extension of the ANS

Norepinephrine and epinephrine

Produces and releases 2 NTS:

Preganglionic

Stimulated by ___ cells of the ANS