10, 11 and 12 - Autonomic Nervous System Flashcards
What is the autonomic nervous system?
The portion of the nervous system that controls most visceral functions and accommodates coordinated responses to external stimuli
Are autonomic disorders being sufficiently considered, suitably investigated and appropriately managed in clinical practice?
NOOOOOO
What accounts for these issues with ANS disorders?
Symptoms are so variable
What does the central nervous system consist of?
Brain
Spinal cord
What does the peripheral nervous system consist of?
Somatic nervous system
Autonomic nervous system
What are the two parts of the somatic nervous system?
Somatic efferent nerves which innervate skeletal muscles
Somatic and visceral afferent nerves
What are the three components of the autonomic nervous system?
Sympathetic division (SANS) Parasympathetic division (PANS) Enteric division (which is closely interconnected with SANS and PANS)
In the sympathetic division of the ANS, the preganglionic fibers are _________ compared to the postganglionic fibers.
Short
In the parasympathetic division of the ANS, the preganglionic fibers are ________ compared to the postganglionic fibers
Long
long pre, short post
Why do parasympathetic fibers have longer presympathetic fibers?
Because they synapse in the wall of the visceral organs, so they have to travel a long way to get there (long pre) but they are very close after they synapse (short post)
What is the one exception to the two-neuron organization of the ANS? (meaning there is a pre and post ganglionic nerve)
The adrenal medulla
Why is the adrenal medulla an exception?
It is considered to be a giant ganglion that does not have post-gaglionic fibers (there fore there is only one nerve, the presynaptic nerve)
What does the adrenal medulla release?
- Epinephrin
- Norepinephrin
- Dopamine
- Peptides
Where are these neurotransmitters released?
Directly into the blood stream
Is activation of the ANS involuntary or voluntary?
Involuntary
Can responses to a stimuli in the ANS be excitatory, inhibitory or both?
Both
What spinal levels contribute to the sympathetic division of the ANS?
The throaco-lumbar section (T1-L3,4) as well as some cranial nerves
At the spinal level, where do the autonomic neurons lie?
The intermediolateral cell column (AKA lateral horn)
Where is the intermediolateral cell column located?
Between the dorsal and ventral horns
Where do axons from preganglionic sympathetic neurons exit the spinal cord?
VENTRAL roots along with axons from somatic motor neurons
From the ventral root, the preganglionic sympathetic neurons branch away from the somatic motor neurons and enter the ____________
White communicantes
Why is the white communicantes white?
Because most preganglionic sympathetic axons are myelinated, making the white communicantes appear white
What is a paravertebral ganglia?
Along the length of the sympathetic trunk are ganglia known as paravertebral ganglia. The ganglia are distinguished as cervical, thoracic, lumbar, and sacral and, except in the neck, they closely correspond to number to the vertebrae.
What is a prevertebral ganglia?
Sympathetic ganglia which lie between the paravertebral ganglia and the target organ