What is the autonomic nervous system?
The part of the nervous system responsible for control of the bodily functions not consciously directed, such as breathing, the heartbeat, and digestive processes.
What is unique about the somatic nervous system compared to the autonomic nervous system?
In the somatic nervous system you have a single lower motor neurone projecting directly to effector muscles (CNS--> effector)
- Effect on somatic nervous system is always excitatory
What neurotransmitter is used in the autonomic nervous system?
What is the enteric nervous system?
The enteric nervous system is a quasi-autonomous part of the nervous system and includes a number of neural circuits that control motor functions, local blood flow, mucosal transport and secretions, and modulates immune and endocrine functions.
What are the effector cells in the autonomic nervous system?
Most of stimuli in autonomic nervous system are going to be internal as opposed to somatic. True or False?
Describe the efferent neurons of the autonomic nervous system
Broken up into 2 neurons
- Preganglionic Neurone
- Post ganglionic Neurone
Cell bodies of preganglionic neuron are found in the CNS and postganglionic cells are found in ganglia.
(ganglia are collections in cell bodies in the peripheral nervous system - outside the CNS)
What 2 major transmitters are used?
Acetylcholine and Norepinhephrine
May either be excitatory or inhibitory effects
What cranial nerves are the parasympathetic outflow nerves?
III, VII, IX & X
What are the visceral afferent nerves?
Information coming backwards from the autonomic nervous system towards the CNS.
They are important in visceral reflexes e.g. standing in a queue at a resturant (e.g. involuntarily salivating after seeing food, pupils dilating after being in a dark room)
How is visceral pain different from somatic pain?
- You can localise it in the somatic nervous system
- In autonomic nervous system, pain is more diffuse - poorly localised.
REFERRED PAIN. (a conjunction between autonomic nervous system and somatic nervous system)
Sympathetic nervous system is referred to as the..
Thorocolumbar Outflow (T1-T2) because the cell bodies of the preganglionic neurons are located in the thorcacic spinal cord and columbar spinal cord
Fight or flight
The parasympathetic nervous system is the..
Craniosacral outflow (CN III, VII, IX & X) + S2, S3, S4
-Rest and digest
Parasympathetic has synergy with enteric system:
- Enteric system is responsible for peristalsis
- GI secretions
Parasympaehtic nervous system upregulates or downregulates enteric nervous system.
Sympathetic and parasympathetic nervous system are controls for the enteric nervous system.
In the parasympathetic nerve, the is the vagus nerve predominantly preganglionic or postganglionic neurons?
The ganglions are either close to the organ, in the organ, or on the organ itself.
So you have a very short post-ganglionic neuron at the other end.
Give an overview of the parasympathetic nervous system
- Preganglionic neurons in the brainstem or sacral spinal cord.
- Brainstem (CN III, VII, IX & X)
- Remember X vagus nerve.
- Long: Preganglionic Short: Postganglionic
- Lateral part of sacral gray
Do the pre ganglionic neurons of the parasympathetic nervous system travel with rami communicates or spinal nerves?
Where would you find nicotinic and muscarinic receptors of the parasympathetic nervous system?
- Muscarinic receptors are longer lasting
- Nictonic receptor at the ganglion
- Muscarinic receptors at the effector cells
Where do you get referred pain?
- Pain is carried by group C nerve fibres
What areas does S1, S2 & S3 parasympathetic nerves innervate?
What are the key features of the parasympathetic nervous system in terms of action?
- Counterbalances sympathetic NS
- Conserves Energy
- Decreases Heart Rate, RR, BP
- Eyes adapted for near vision
- Increase GIT motility and secretion
- Increase smooth muscle activity
- Sphincteric Relaxation
Where do the Pre-ganglionic neurons of the sympathetic nervous system originate from?
PreG neurons from laternal horn, T1-L2
Give some facts about the preganglionic neurons of the sympathetic nervous system
- Short preganglionic neurons, long postganglionic neurons
- Come from lateral horn found in T1-L2 regions
- There are Two sets of ganglia - paravertebral and prevertebral ganglia
- Paravertebral ganglia are the sympathetic trunk
- Inferior mesenteric ganglia - hindgut region
- Superior/Inferior/Mesenteric plexus - where are they?
Celiac - foregut region
- Grey ramus commicantes take the post gangliotic neuron to whereever it's going
Give some facts about the postganglionic neurons of the nervous system
Post gaglionic to body wall and limbs via spinal nerve rami communicates
- Post ganglionic to thoracic organs direct to organ
- PreG to abdominal organs - splanchic nerves via prevertebral ganglia
Single effector > or equal to 1 type of receptor -> results in stimulation depends on receptor interaction
What are the neurons and neurotransmitters of the sympathetic nervous system?
Top one is more predominant one.
Sympathetic nervess at postganglionic tend to be noradrenergic
Acetylcholine secreted at both ends
At sweat glands you have muscarinic receptors
Synaptic stimulation results in noradrenaline release locally, nor noradrenaline/adrenaline release into circulation
- Effects are wide-spread and long -lasting (flight or fight)
Few 'nitroxidergic' post ganglions are nitroxidergic --> release NO promoting vasodilation
What is Horner Syndrome?
All to do with sympaehtic innervation to the face
The sympaethetic system innervates your iris
But it inntervates the dilator muscles of your iris.
(sweat glands of face are also supplied by sympathetic nervous system)
Upper eyelid however has couple of muscles (one is voluntary, one involutnary).
The involutnary part of the elevator of the upper lid is innervated by the sympathetic nervous system
We need this because when we look up you want the upper eyelid to move out of the way of the ascending pupul.
So when you lose sympaehtic nervous systme to your face, you get a lazy upper eyeld.
Hence the eye ends up hanging lower than it should do.
On the same side you also get dysfunction of the sweat glands
And unopposed constrictor action from the parasympaehtic nervous system.
Give an overview of the innervations of the sympathetic nervous system
Describe the Sympathetic Nervous System
Give an overview of the neurons and neurotransmitters in the autonomic nervous system
- All preganglionic neurons (whether in sympathetic or parasympathetic nervous system) are cholinergic.
- They are all released onto nicotonic receptors.
The bottom two are sympathetic to the sweat glands
1. Sympathetic to sweat glands
They are very similar!
What are the principal features of the sympathetic and parasympathetic nervous system
What are the key functional interactions of the autonomic nervous system including parasympathetic and sympathetic divisions?
How is bladder control innervated by the autonomic nervous system?
Sympathetic - where negative, inhibiting whatever it happening. Can use sympathetic nervous system to turn off the parasympathetic nervous system. Sympathetic nervous system is excitatory to the bladder neck. Sympathetic to you because it stops you from weeing yourself.
Parasympathetic - bladder emptying when activated
What happens if you get complete transection or hemisection of the spinal cord?
IF injury at sacral level then you have loss reflex emptying bladder