4. DSA Autonomics

Question 1

What are the divisions of the PNS?

Answer 1

Sensory (afferent) –> Somatic sensory (body touch pain pressure) and visceral sensory (visceral pain stretch temp) Motor (efferent)–> 1. Somatic (motor of all skeletal muscles) 2. Autonomic Nervous system –> sympathetic and parasympathetic division

Question 2

What is the function of the ANS?

Answer 2

To regulate unconscious body functions and maintain internal physiological homeostasis, consisting of a 2 neuron system with presynaptic (preganglionic) neurons in the CNS and postsynaptic neurons (postganglionic) located in the periphery

Question 3

What does the sympathetic/catabolic division of the ANS do? (3)

Answer 3

1. Expends energy -fight/flight 2. Responsible for all vasoconstriction of vessels 3. In all vascularized portions of the body

Question 4

What does the parasympathetic/anabolic division of the ANS do? (3)

Answer 4

1. Conserves energy - rest and digest 2. only in head neck, body cavities and genitalia 3. Not in periphery 4. Glandular secretions except sweat glands

Question 5

What are the differences in length, branching and type of NT released by postsynaptic axons between sympathetic and parasympathetic?

Answer 5

Sympathetic: Long postsynaptic fibers, highly branches, adrenergic (norepinephrine) Parasympathetic: Short postsynaptic fibers, few branches, release acetylcholine (cholinergic)

Question 6

Sympathetic presynaptic (preganglionic) neurons are found in the lateral/grey horn, found in T1-L2, which are linked into short nerves into sympathetic trunks containing postsynaptic neurons, what does it supply?

Answer 6

Entire body with sympathetic innervation

Question 7

From the CNS, the presynpatic neurons leave and synapse on clusters of neuron cell bodies arrange superior to inferior on both sides of vertebral bodies forming a chain of ganglia. What is this chain and what does it do?

Answer 7

Also know as the sympathetic chain/paravertebral ganglia, this is where the synapsing occurs

Question 8

T1-L2(3) has a section with presynpatic sympathetic neuron cell bodies, in the intermediolateral (lateraL) column. Axons leave via ventral root and enter what where they synapse with what?

Answer 8

Enter the sympathetic trunk (chain) where they synapse with postsynaptic sympathetic neurons

Question 9

Neurons leave the spinal cord by white (pre) rami communicans and what do grey (post) communicans do?

Answer 9

Grey rami communicans allow postsynaptic axons to reenter the spinal cord.

Question 10

White rami are only found at T1-L2 because they have presynaptic neurons, Where can grey rami be found?

Answer 10

They will be found from C1 to the coccyx-1 (Co1) as postsynaptic sympathetic innervation

Question 11

Sympathetic presynaptic neurons in lateral horn of spinal cord send myelinated axons throuhg ventral root into spinal nerves. White communicans carry these axons from the spinal nerve to the associated sympathetic trunk ganglia where they synapse. Gray rami communicans carry…?

Answer 11

Postsynaptic sympathetic fibers back to the spinal nerve to travel to peripheral structures

Question 12

Sometimes in cervical/sacral levels, axons carried by white rami enter above or below its vertebral level in order to?

Answer 12

In order to synapse with postsynaptic neurons at other levels

Question 13

What is the sympathetic pathway via prevertebral (collateral) ganglia? (5)

Answer 13

1. Axons pass through the sympathetic trunk and exit on throacic splanchnic nerves (to viscera) 2. Found only in abdomen and pelvis 3. Lie anterior to vertebral column 4. Synapse in prevertebral (collateral) ganglia on the abdominal aorta, celiac and superior and inferior mesenteric ganglia 5. Inhibit activity of muscles and glands in visceral organs

Question 14

What is the role of the adernal medulla in the sympathetic division? (T8-L1)

Answer 14

It is a major oggan of the sympathetic nervous system, in which the sympathetic preganglionic fibers synapse on medullary chromaffin cells. Cromaffin cells release great quantities of norepinephrine and epinephrine into the blood when stimulate. ** exception to the 2-neuron pathway for ANS**

Question 15

White rami are located from T1 to L2/3 spinal nerve levels while gray rami for body walls and limbs are found from C1 to Co1 (entire spinal cord) to enter all spinal nerves. What happens in the sacral region?

Answer 15

Gray rami entering spinal nerves are reffered to as sacral splanchnic nerves

Question 16

The parasympathetic nervous division consists of a two-neuron system where presynaptic neurons are located within the CNS and leave via?

Answer 16

cranial nerves or pelvic splanchnic nerves (brainstem/S2-S4) to enter the viscera, where they synapse neurons within the organ *presynapthic parasympathetic axons tend to be much longer than postsynaptic*

Question 17

Cranial portion: axons of presynaptic parasympathetic neurons leave the brainstem in cranial nerves III VII, IX, X Sacral portion:

Answer 17

Located in the interomedialateral cell columns of the S2-S4 sacral spinal cord, presynaptic fibers pass through anterior rami and branch off as pelvic splanchnic nerves that make their way to pelvic viscera via hypogastric plexus (Later in GI)

Question 18

What is important of the enteric nervous system? (3)

Answer 18

1. Consists of neurons in the wall of the gastrointestinal tract from the esophagus to the anus 2. Capable of autonomous functions such as the coordination of GI reflexes 3. Enteric neurons also include postsynaptic neurons of cranial nerve X and pelvic splanchnic nerves.

Question 19

What is important to remember about the sympathetic nervous system? (6)

Answer 19

Question 20

What is important to remember about the parasympathetic nervous system? (5)

Answer 20