PNS and ANS Flashcards
What are the posterior rami?
dorsal branch
posterior division of the spinal nerve
What is the anterior ramus?
Ventral branch
anterior division of the spinal nerve
What is a plexus?
Branching network of vessels/nerves
What is a ganglion?
Nerve cell cluster / group of nerve bodies in ANS/sensory system
What are afferents?
Input nerve fibres (receive sensory info) - dorsal
What are efferents?
Output nerve fibres (motor supply) - ventral
What is the dura?
Thick outer meningeal layer attached to skull
What is the arachnoid?
Layer containing arachnoid spaces / BBB for exchange between blood and csf
What is the pia?
protective layer directly over the brain - continues down spinal cord
What are white ramus communications?
preganglionic sympathetic nerve tract fibres from spinal cord
What are the grey ramus communications?
postganglionic nerve fibres for sympathetic tract
What are intercostal nerves?
11 Spinal nerves emerging from vertebral column and run along with the ribs
1 subcostal runs under rib 12
What does the vagus nerve innervate?
Vagus nerve (CNX) parasympathetic innervation to thorax and abdomen
What does the phrenic nerve innervate?
Phrenic nerve (C3,4,5) supplies diaphragm - important for breathing
What are the cervical and lumbar enlargements?
Attachment of large nerves supplying upper limb (C5-T1)
What is the conus medullaris?
Where the spinal cord terminates at a tapering point
starts around L1/2
What is the cauda equina?
Many dull, yellow coloured nerve roots (L2-L5)
- hangs like a horse tail ‘equina’
What is the filum terminale?
A single white fibrous cord - anchors spinal cord
What structure encases the spinal cord?
Spinal cord is enclosed within a tough fibrous dural sac
- spinal dura continuous with cranial dura at foramen
magnum
What lines the dural sac?
Arachnoid - transparent membrane
What is the denticulate ligament?
Serrated ligament found on either side of spinal cord between dorsal and ventral roots
What is the role of the sympathetic chain?
Communicates with the spinal nerves via white and grey rami
- clearly seen in thoracic region
Where are parasympathetic preganglionic fibres?
In brainstem (CN) or sacral region of spinal cord
