L5 Autonomic Nervous System

Question 1

There are NO Sympathetic Fibers from ________________

There is NO Autonomic outflow from the _______________

Parasympathetic almost entirely from _____________, small amount from _______________

Answer 1

There are NO Sympathetic Fibers from CRANIAL NERVES

There is NO Autonomic outflow from the CERVICAL SPINE

Parasympathetic almost entirely from CRANIAL NERVES small amount from SACRAL SPINE

Question 2

Sympathetic vs. Parasympathetic Pre/Post Ganglionic Length

Answer 2

Sympathetic nervous system: “fight or flight” – broadly stimulating. SHORT preganglionic fibers, LONG postganglionic fibers

Parasympathetic nervous system: “rest and digest” – broadly relaxing . LONG preganglionic fibers, SHORT postganglionic fibers

Question 3

Defining characteristic of the autonomic nervous system?

Exception to the rule?

Answer 3

EXCEPTION: The adrenal medulla cells targeted by sympathetic pre-ganglionic fibers release Noradrenaline and are derived from neural crest, like postganglionic => Can be considered “Neurons w/o Axons”

Question 4

With the exception of _____________, ALL neurons with cell bodies outside CNS are part of the autonomic nervous system

Answer 4

With the exception of Sensory Neurons, ALL neurons with cell bodies outside CNS are part of the autonomic nervous system

Question 5

In the sympathetic Nervous system, most of the ganglia are ___________

Answer 5

In sympathetic Nervous system most of the ganglia are Paravertebral

Question 6

Axons ENTER through ________ and EXIT through _______ Ramus

Answer 6

Axons ENTER through WHITE and EXIT through GRAY Ramus

Question 7

Defining characteristic of the autonomic nervous system?

Exception to the rule?

Answer 7

EXCEPTION: The adrenal medulla cells targeted by sympathetic pre-ganglionic fibers release Noradrenaline and are derived from neural crest, like postganglionic
=> Can be considered “Neurons w/o Axons”

Question 8

Answer 8

Question 9

Neurotransmitter and Receptor of Each Post-Ganglionic Cell and Target Tissue

Answer 9

Question 10

Parasympathetic neurons can be targetted with drugs like Atropine. How is this Possible?

Answer 10

Atropine Targets JUST Nicotinic Receptors

Question 11

Post-Ganglionic neurons release neurotransmitters from ________________ not Terminal Synapses

Answer 11

Post-Ganglionic neurons release neurotransmitters from Varicosities not Terminal Synapses

Question 12

What are NANCs and what is their role?

Answer 12

NANC (non-adrenergic/non-cholinergic) Transmitters are released alongside classical transmitters (NA or Ach) and include Purines (ATP), Nitric Oxide and Neuropeptides

Question 13

Everything outside of central nervous system arrises from ________

Answer 13

Everything outside of central nervous system arrises from NEURAL CREST

Question 14

Development of the Autonomic Nervous System:

• Neural crest cells migrating along the ___________ path => SENSORY NEURONS and AUTONOMIC (Post-Ganglionic) NEURONS.
• Autonomic cells arise from distinct cells which continue to migrate __________ attracted by factors such as _________ which is highly expressed in Heart/Aorta ect

Answer 14

• Neural crest cells migrating along the MEDIAL path => SENSORY NEURONS and AUTONOMIC (Post-Ganglionic) NEURONS.
• Autonomic cells arise from distinct cells which continue to migrate VENTRALLY attracted by factors such as BMP-2 which is highly expressed in Heart/Aorta etc (Signals can be switched back on in the adult! Ischemic heart injury => increased expression of nerve growth factors => sprouting of additional sympathetic fibers to the heart)

Question 15

Development of the Enteric Nervous System:

Enteric Nervous System is ____________-____________

• Progenitor cells (ENCCs) from developing ________ nerve migrate down the developing gut
• Final part is innervated by ENCCs of ________ origin. Developmental error => NO neurons in the lowest part of the gut (______________)

Answer 15

Enteric Nervous System is ROSTRO-CAUDAL (Front to Back) NOT Dorso-Ventral

• Progenitor cells (ENCCs) from developing VAGUS nerve migrate down the developing gut
• Final part is innervated by ENCCs of SACRAL origin. Developmental error => NO neurons in the lowest part of the gut (Hirschsprung’s Disease)

Question 16

How do autonomic neurons know which transmitter to use?

Answer 16

Target cell controls the phenotype of the neuron innervating it

Question 17

What type of injury results in the most severe impact on Autonomic Function?

Answer 17

Most pronounced in Cervical Injury => disconnect sympathetic outflow and sacral parasympathetic outflow from cortical / brainstem influence

Question 18

Acute vs. Chronic Phases of Autonomic Injury?

Answer 18

Question 19

What is Autonomic Dysreflexia?

At what level of Spinal Injury does this occur?

Effects?

Answer 19

Question 20

Cranial Nerves Involved in the Parasympathetic Outflow?

Answer 20

Cranial nerves involved in the parasympathetic nervous system are the:

• Oculomotor (CNIII)
• Facial (CNVII)
• Glossopharyngeal (CNIX)
• Vagus Nerves (CNX)