1. Autonomic Nervous System

2. Main input from autonomic sensory neurons (most associated with interoceptors)
monitor internal environment- not conscious
example- chemoreceptors for CO2 level

3. Autonomic motor neurons regulate visceral activities
(increase or decrease)
function somewhat even if nerve supply damaged
example- heart beat
difficult to consciously control
(i.e. lie detector test, yoga)

4. See figure 15.1
Most autonomic motor pathways consist of two motor neurons
in series through autonomic ganglion (second not myelinated)
preganglionic (CNS) and postganglionic (PNS)
some extend to adrenal medullae- hormones released

5. The preganglionic motor neurons of the sympathetic system arise in the spinal cord.
They pass into sympathetic ganglia which are organized into two chains that run
parallel to and on either side of the spinal cord.

7. The main nerves of the parasympathetic system is the tenth cranial nerve, the vagus nerve. It originates in the medulla oblongata. Other preganglionic parasympathetic neurons also extend from the brain as well as from the lower tip of the spinal cord.

9. Anatomy of autonomic motor pathways:
Three types of autonomic ganglia
sympathetic trunk ganglia- vertical row on either side of vertebral canal
sympathetic division
innervate organs above diaphragm
prevertebral ganglia- anterior to vertebral canal
innervate organs below diaphragm
terminal ganglia- close to or actually in wall of organ (longer)
parasympathetic division
Postganglionic neurons- one sympathetic ganglia can synapse with 20+ postganglionic neurons (effect much of body simultaneously)

11. Autonomic plexuses
tangled networks of axons from sympathetic and parasympathetic neurons
cardiac (heart), pulmonary (lungs), celiac or solar (liver, gallbladder, stomach, pancreas, spleen, kidneys, testes, ovaries), superior mesenteric (small and large intestines), inferior mesenteric (large intestine), renal (kidneys and ureters)

12. ANS neurotransmitters and Receptors
cholinergic- release acetylcholine (Ach)
all preganglionic neurons, parasympathetic postganglionic neurons, some sympathetic postganglionic (sweat glands)
nicotinic and muscarinic receptors- effects brief
adrenergic (release norepinephrine/ NE)
most sympathetic postganglionic
alpha and beta receptors- longer lasting
agonists can activate receptors, antagonists block receptors

14. Physiological effects of ANS- tables 15.3 and 15.4
autonomic tone- balance between sym. and parasym.- regulated by hypothalamus
Sympathetic dominates during physical or emotional stress (rapid ATP production)--- flight or fight response--- “E situations” (exercise, emergency, excitement, embarassment)
Parasympathetic dominates “rest and digest” activities- conserve and restore energy --- SLUDD (salivation, lacrimation, urination, digestion, defecation)

16. Autonomic reflexes- controlled conditions (i.e. blood pressure)
reflex arc: receptor- sensory neuron- integrating center- motor neuron- effector
hypothalamus major control center