Lecture 15: ANS Pain Flashcards
How many neurons are in the pain system?
Two neurons
Where is the preganglionic and post-ganglionic neuron in the pain system found?
The preganglionic neuron is in the CNS and the axon is in the PNS
The postganglionic neuron is in the peripheral nervous system
What is the autonomic NS responsible for innervating?
Visceral tissues:
Internal organs
Smooth muscles
Glands of skin
What are the two divisions of the autonomic nervous system?
Sympathetic and Parasympathetic
What can the sympathetic and Parasympathetic system be likened to?
The on and off
How does the sympathetic system affect the lungs, heart and gut?
It increases lung capacity and HR and turns of the gut
How does the parasympathetic nervous system affect the lungs, heart and gut?
It decreases HR and lung capacity and turns on gut
What is the sensory portion of the autonomic nervous system?
Visceral afferent fibres that sense pain only
How many neurons are in the visceral afferent pathway?
One neuron
What pathway is used in the somatic motor system?
Corticospinal tract and corticobulbar tract
Where in the spinal cord is the motor neuron in the somatic motor system?
In the ventral horn, travels to the ventral root and to each spinal nerve
How many neurons are in the autonomic motor pathway?
Two neurons
How many neurons are in the autonomic motor pathway?
Two neurons
What are the two neurons in the autonomic motor pathway?
Preganglionic and post ganglionic neurons
Where is the postganglionic neuron of the autonomic motor system located?
In the PNS in an autonomic ganglion
Where does the postganglionic neuron of the autonomic motor system go to?
Visceral targets:
- Cardiac muscle
- Glands
- Smooth muscle
What is the general pathway of preganglionic neuron in the motor autonomic pathway?
Preganglionic neurons go through the ventral root and extend axons out to join with the spinal nerve to find the autonomic ganglion
What has visceral afferents?
All organs
What sensations do somatic afferents sense?
Many sensations - Hot, cold, pressure, itch, light touch, dull pain, sharp pain
What sensations do visceral afferents sense?
Visceral afferents only sense pain
How can the pain by visceral afferents be described?
Vague, dull, ill localized and poorly focused
What is another name for Sympathetic motor outflow?
Thoracolumbar outflow
What is another name for Parasympathetic outflow?
Craniosacral outflow
What is another name for Thoracolumbar outflow?
Sympathetic
What is another name for Parasympathetic outflow?
Craniosacral outflow
Where in the spinal cord does Thoracolumbar outflow originate?
Thorax and lumbar spinal cord
Where in the spinal cord does Craniosacral outflow originate?
Brainstem and sacral spinal cord
Through what nerves does the autonomic nervous system affect salivation?
VII - Facial
IX - Glossipharyngeal
Through what nerve does the autonomic nervous system affect pupil diameter?
CN III - Oculomotor
What is the sympathetic response of pupil control?
Increase pupil diameter
Where does the somatic nervous system originate?
From the somatic mesoderm
What originates from the somatic mesoderm?
The somatic nervous system
What innervates skin, muscles, bones and body walls?
The somatic nervous system
What does the somatic nervous system innervate?
Skin, muscles and bones of body walls and parietal membranes
What parietal membranes does the somatic nervous system innervate?
Pleura
Pericardium
Peritoneum
Periosteum
What innervates the:
Pleura
Pericardium
Peritoneum
Periosteum
The somatic nervous system
What do the motor nerves of the somatic nervous system supply?
Skeletal muscles
What do the sensory nerves of the somatic motor system sense?
Pain, temperature, touch, chemoreception
Describe the pain sensed by the somatic nervous system
Sharp and well localized
Where does the Visceral/Splanchnic PNS originate?
The splanchnic mesoderm
What originates from the splanchnic mesoderm?
The Visceral/Splanchnic PNS
What does the Visceral/Splanchnic PNS innervate?
Viscera - heart, lungs, liver, glands, blood vessels (smooth muscle), gut uterus, etc
Visceral membranes (PPP)
What vertebral layers does the sympathetic nerve supply?
T1-L2
What portion of the autonomic nervous system is T1-L2?
Sympathetic
What nerves and portions of the spinal cord are supplied by the Parasympathetic nervous system?
CN III - Oculomotor
CN VII - Facial
CN IX - Glossopharyngeal
S234 - Sacral
What is the Sensory supply of the Autonomic nervous system
Visceral afferents travel with sympathetic and vagus (X) and respond to stretch and ischemia
Describe the sensation of pain sensed by the autonomic nervous system
Pain sensed by the autonomic nervous system is dull, vague and ill focused. Only exception is baroreceptors - this sensation is not painful
Describe the innervation of the somatic nervous system to the body wall
The Thorax and abdomen have two layers. An inner visceral layer and a parietal layer that lines the body wall.
The Parietal layer is innervated by the somatic nervous system so pain from this area is very specific
What is the pathway of a typical motor neuron from the spinal cord?
The LMN in the ventral horn project to the spinal nerve and bifurcates to travel the dorsal primary ramus or primary ventral ramus
What is the pathway of a typical sensory neuron to the spinal cord?
Axons from the dorsal primary ramus and ventral primary ramus join and enter the spinal cord and enter the dorsal root
Where are preganglionic parasympathetic cell bodies found?
In the brainstem
III - Oculomotor
VI - Abducens
IX - Glossopharyngeal
X - Vagus
Sacral Spinal Cord
S2, S3, S4
Where are postganglionic parasympathetic cell bodies found?
In the autonomic ganglia close to their target organ/gland
Where are preganglionic sympathetic cell bodies found?
In the spinal cord at T1-L1/2
Where are Postganglionic sympathetic cell bodies found?
In the paravertebral (sympathetic chain) or prevertebral autonomic ganglia (in abdomen)
What is contained in the dorsal horn of the spinal cord?
Sensory neurons
What is contained in the Ventral horns of the spinal cord?
Motor neurons
What is contained in the Lateral horn of the spinal cord?
Preganglionic sympathetic cell bodies
Where are preganglionic sympathetic cell bodies found?
In the lateral horn of the spinal cord