W3 - Peripheral NS Flashcards
What are the divisions of the PNS and what are the divisions of these?
Sensory (afferent) - Somatic + visceral, Motor (efferent) - Somatic + autonomic (symp/parasymp)
What division of the PNS does taste/smell and hearing/vision come under?
Taste/smell - visceral sensory, Hearing/vision - somatic sensory
What motor division does innervation of all skeletal muscles come under?
Somatic motor
What motor division does innervation of the cardiac muscles come under?
Autonomic motor (symp/para)
What root from SC, dorsal/ventral, has sensory or motor neurons?
Dorsal root - sensory, Ventral root - motor
What is in the dorsal root ganglion and ventral horn?
DRG - sensory cell bodies, Ventral horn in SC - motor cell bodies
What is a ganglion?
A cluster of many nerve cell bodies
What does a spinal nerve consist of and what is a ramus?
Spinal nerve has mixed sensory + motor neurons and ramus are branches of the spinal nerves
What is the function of the fat layer within the meninges and where do nerve roots leave the spine to form spinal nerves?
Protection/cushioning, leave spine through intervertebral foramen (weakest place in spine)
There are 31 pairs of spinal nerves, where do they supply (+not)?
All of body but not head
How many cervical, thoracic, lumbar, sacral and coccygeal spinal nerves?
C - 8, T - 12, L - 5, S - 5, C - 1
Where do peripheral nerves originate?
CErvical region or sacral region
What do you call a single major intercostal nerve from a single spinal nerve?
The trunk
During development, plexi become mor comlpex, what is a nerve plexus? (e.g. brachial plexus)
An interwoven network of nerve fibres
Where do ramus communicans branch from?
T1-12 then L1-3
Ramus communicans connect to sympathetic chains either side of the spine, what is a symp chain?
Linked sympathetic ganglia
What do you can an area of skin which is innervated by sensory axons of a single spinal nerve?
Dermatome
The spinal nerves dont always line up with/innervate the territory of the spinal levels in which they arise (think dermatomes), ture or false?
True
What do you call the continuations of the dura, arachnoid and pia mater that surround nerves?
Dura - epineurium, Arach - perineurium, Pia - endoneurium
Do nerve coverings surround only one nerve?
No may be one nerve but can be bundles of many nevres
What is the function of the epineurium, perineurium and endoneurium?
Epi - Provides strength, Peri -, Endo -
Schwann cells maintain the environment (pH/glucose), do all neurons need them?
Yes
Why are the two reasons a larger diameter fibre conduct APs faster?
Less organelles in the way, more myelin allowing for saltatory conduction
The perineurium surrounds fascicles, what do the perineurial cells have to form a barrier between nerves and external environment?
Tight junctions
