Editing 20110106 Lecture 5 notes.txt

*started here on 01/06/2011 at 8:20AM.


===Learning Objectives===
#Understand the division of the Autonomic Nervous System (ANS) into Sympathetic and Parasympathetic subsystems 
#Understand the anatomic & physiologic differences between these two divisions 
#Understand the functions controlled by the Autonomic Nervous System 

===The autonomic nervous system is responsible for maintaining the constant internal environment in our body===
*The ANS includes the parasympathetic and sympathetic nervous systems and the enteric nervous system
**Enteric covered in GI lectures.

===The autonomic nervous system overview===
*Parasympathetic and sympathetic produce opposite effects.
**The excpetions are the sweat glands, blood vessls; only get sympathetic innervation.
*The ANS focuses on regulating smooth muscle, heart rate, and glands.
**BP, heart rate, pupil size, one more

===The sympathetic and parasympathetics are two-neuron systems===

===Sympathetic division of the autonomic nervous system===
*AKA thoracolumbar division
*The sympathetics are in the lateral horns of the spinal cord, between t1 and l3.
*Presynaptic axons go to the sympathetic ganglion
*The superior cervical ganglion innervates the head.
*The middle cervical ganglion innervates the lung and heart.
*The adrenal medulla and the sweat glands and errector pilli and blood vessels only receive sympathetic innervation.

===Sympathetic neuron routes===
*Preganglionic sympathetic neurons reside in the lateral horns of the spinal cord (Tl -L3)
*There are two types of sympathetic fibers:
**B type which are myelinated
**C type which are unmyelinated
*The sympathetic nerves pass through the white ramus
**White because it is mostly myelinated fibers.
*Some will synapse in the ganglion, others will travel along the (caudally or coronally) along the chain.
**Others will move out of the chain, even.
*Those that synapse in the ganglion, then leave via grey rami to join the spinal nerves again to travel to the effector cells.
*Those (presynaptics) that move through the ganglia without synapsing move on to paravertebral ganglion (around the aorta, very short distance away) to synapse
**Paravertebral ganglia are around the aorta (celiac, mesenteric, etc.)
*Most nerves synapse on many (around 200) ganglia, not just one.
*Sympathetic post-synaptics generally follow blood vessels

===Adrenal Medulla===
*Fight or flight response
**Starts in the lateral horn of T10 through L1
**Moves along splanchnic nerves
***Unmyelinated = C type fibers
**Reaches adrenal medulla
**Activates chromatin cells via neuronal region
***Considered to be part of the sympathetic nervous system

===Catecholamine exocytosis===
*Splanchnic nerves synapses on chromaffin cells
**Splanchnic nerves release vesicles with acetylcholine
**Chromaffin cells have ach receptors
*When chromafinn cells bind the acetylcholine receptors, Na channels are opened such that Na rushes into the chromaffin cell.
*Upon Na efflux, the voltage changes causing depolarization
*Then voltage-gated Ca+ channels open because of initial depolarization
*Dense core vesicles have catecholamines
 **Usually catecholamines in clear vesicles, but these ...?
*Epinepherine and norepinepherine released into the blood by vesicle release
 Does epithelial cell of the blood vessel have to take it up and release it?

===Parasympathetic nervous division===
*AKA craniosacral
*Nerves come from S2-S4 and the brain
*Oculomoter = CN3
**Invervates the eye
*Sympathetic ganglia are very close to the spinal cord
**B type fibers are very short (presynaptic)
 Are presynaptic fibers of sympathetic system always of type B?
*Parasympathetic presynaptic fibers are very long and post-synaptic fibers are short.
*There are only 4 parasympathetic ganglia
**Pterogopalatine
**Submandibular
**Otic
**Ciliary
**These provide much of the innervation to glands of the head

===The brainstem nuclei associated with cranial nerves Ill,VII, IX, and X host parasympathetic preganglionic neurons===
*CN3 comes from the Edinger-Westphal nucleus and travels to the ciliar ganglion
*CN7 comes from the superior salivatory nucleus and travels to the pterygopalatine and submandibular ganglia
*CN9 comes from the inferior salivatory nucleus and travels to the otic ganglia
*CN10 comes from ...
 CN X originates from the nucleusambiguus, as well as the dorsal motor nucleus of the vagus and travels to terminal ganglia in the viscera ofthe thorax and abdomen 

===Autonomic nervous system chemistry===
*Parasympathetic presynaptic are long and release ach.
*In parasympathetic ganglia, the nicotinic receptor is expressed.
*Parasympathetic effector cells generally express muscarinic g-protein receptor.
*Sympathetics are in the lateral horn and have short pre-synatpic fibers
*Sympathetic effector cells generally express adrenergic receptors.
**There are alpha and beta adrenergic receptors.
**Epinepherine can bind at adrenergic receptors, mostly beta versions
***Heart, etc.
 What is used to signal at the sympathetic ganglia?

===Autonomic postganglionic axons do notform true synapses===
*Vesicles are released to provide NT for smooth muscle stimulation.
*Two types of smooth muscle:
**Multiunit
***Ex: smooth muscle of the eye
**Singleunit
***Blood vessels
***Connected wtih gap jxns
***NT from post-ganglionic nerve affects one cell and AP is passed from smooth muscle to smooth muscle by gap jxns

===Autonomic Functions===
*Pupil:
**Para constricts, sympathetic dilates
*Sweat glands
**Para no action, symp secretion
*Blood vessels
**Para no action, symp constrict or dilate (alpha-1-R, beta-R
*Muscle
**Para no action, symp constrict
*Heart rate
**Para decreases, symp increases
*Bronchioles
**Para constricts, symp dilates
*GI
**See slide

===Ganglionic sympathetic neurons expressnicotinic acetylcholine receptor-channels===
*was laughing too hard about "practicing"
 This and the remaining slides were unclear.

===Metabotropic receptors on the target cells===
*Metabotropic receptors are usually g-protein receptors.
**They differ by what the g-protein activates.
**This is how we have different reactions for different tissues.
 *He went over each of these three figures and highlighted pretty much all the text at the bottom
 *Then he got worried about time and moved on w/o talking about the last of the three.

===alpha-1 and m1-muscarinic receptors===
*Thes modulate cation channel activity in smooht muscle cells.
 **They do this by modulating Gq11?

===References ===
*Baron W.F., Boulpaep E.L. Medical physiology, Elsevier Saunders, Second Updated Edition, 2009
*Koeppen B.M., Stanton B.A. Berne and Levy Physiology, 6th Updated edition, Elseiver-Mosby, 2010 
*Guyton A.C., Hall J.E. Textbook of medical physiology, ElsevierSaunders, 11th Ed., 2006 
*Purves D., Augustine G.J., Fitzpatrick D., Hall W.C., LaMantia A-S., McNamara J.O., Williams S.M. Neuroscience, Sinauer Associates, Inc., 3rd Ed., 2004 
*Netter F.H. Atlas of human anatomy. Elsevier Health Sciences, 2006 


*stopped here on 01/06/2011 at 9AM