L13 Nerves of the Thoracic Cavity Flashcards
Which division of the nervous system contains nociceptive signal?
Sympathetic nervous system
The parasympathetic system however contains mainly signals concerned with the non-sensory aspects of the visceral afferent function.
How is the spinal cord divided?
8 pairs of Cervical spinal nerves 12 pairs of Thoracic Spinal nerves 5 pairs of Lumbar spinal nerves 5 pairs of Sacral spinal nerves 1 pair of Coccygeal spinal nerves
What does the spinal nerve contain?
Afferent and Efferent fibres from the dorsal and ventral roots
What nerves does the ventral root contain?
Motor efferent fibres
What nerves does the dorsal root contain?
Sensory afferent fibres
What is the dorsal root ganglia?
The cell bodies of sensory neurons known as first-order neurons are located in the dorsal root ganglia.
Where do parasympathetic nerves originate from?
The cranial region or the sacrum region
Where do sympathetic nerves originate from?
The thoracic region of the spinal cord and the first two Lumbar segments (T1-L2).
What is the difference in nerve lengths in the parasympathetic nervous system compared to the sympathetic nervous system?
Parasympathetic nervous system: long preganglionic fibres and short postganglionic fibre. The vagus nerve has a really long preganglionic fibre, and synapses near the organ it is innervating.
Sympathetic nervous system: the preganglionic neurone is short relative to the long postganglionic neurone.
How does the length of the nerve before the sympathetic chain compare to that in the sympathetic chain?
The fibres leave the spinal cord and enter the sympathetic chains. The sympathetic chain is longer than the fibres contributing to it. This means that the fibres when leaving the spinal cord can go up and down the body. The chain is therefore slightly longer than its contribution from the spinal cord.
What is the white rami communicans?
White rami communicants carry preganglionic sympathetic fibres from the spinal nerves to the sympathetic ganglia. These are myelinated neurones.
What is the grey rami communicans?
Grey rami communicants carry postganglionic sympathetic fibres from the sympathetic ganglia to the spinal nerves. Thes are unmeylinated neurones.
What is referred pain? Use the sample of the heart.
There is a lot of sensory information from the dermatome. When there is innervation from the heart, the brain gets confused as to whether the pain is from the heart or the dermatome. The sensory afferent fibres receive information at the same level. The pain is then referred to the corresponding dermatome.
The diaphragm - sensory fibres go to C3-5. The brain refers to the pain to the diaphragm.
What are splanchnic nerves?
Splanchnic nerves: paired visceralnerves, carrying fibres of the autonomicnervoussystem (visceral efferent fibres) as well as sensory fibres from the organs (visceral afferent fibres).
Give the root of 3 nerve paths to-and-from the sympathetic chain.
- A motor efferent fibre will move through the ventral root and into the white rami comminicus to enter the sympathetic chain. At the level of the sympathetic chain, the nerve synapses. The post-ganglionic neurone can then transmit the signal up and down the body.
- Another path a neurone can take is, once it has jumped into the sympathetic chain, it can synapse and head towards the relevant organs. The splanchnic nerve is how sympathetic nerves get to target organs. The nerve is named after the relevant organ it innervates e.g. the cardiac splanchnic nerve.
- A nerve could otherwise use the white rami to enter the sympathetic chain. From which it synapses onto the postganglionic neurone. The postganglionic neurone can use the grey rami communicans to enter back onto the spinal nerve to innervate body wall e.g. for sweat production.
