Unit 4 Lecture 30 Flashcards
How do nerves enter and exit the spinal cord?
In segments
Label the spinal nerves
Cervical nerves - 8
Thoratic nerves - 12
Lumbar nerves - 5
Sacral nerves - 5
Coccygeal nerves - 1
What is an enlargement in the spinal cord?
Thick parts of the spinal cord where there’s a lot of nerves
- the extra nerves are supplying limbs
What are the 3 main enlargements of the spinal cord?
- Cervical enlargement
- Lumbar enlargement
- Cauda Equina
Where is the cervical enlargement?
C4-T1
What do the nerves at the cervical enlargement supply?
Shoulder girdle and upper limbs
Where is the lumbar enlargement?
T9-T12
What do the nerves at the lumbar enlargement supply?
Pelvis and lower limbs
Where is the Cauda Equina?
The long nerves at the end of the spinal cord (horse tail)
What do the nerves in the cauda equina PROBABLY supply?
bladder, lower limbs, pelvis
What are plexus?
A bundle of nerves
Where is the cervical plexus?
C1-C5
Where is the Brachial plexus?
C5-T1
Where is the lumbar plexus?
L1-L4
Where is the sacral plexus?
L4-S4
How does a spinal tap work?
Spinal cord proper ends at L2 and the dura/arachnoid layers end at S2…… this makes a cavity to withdraw CSF
What are the spinal meninges?
Pia mater, arachnoid layer, and dura mater
What is found between the dura mater and arachnoid later?
Subdural space
What is found between the arachnoid layer and pia mater?
Subarachnoid space
What is found in the subarachnoid space?
CSF
What makes up the grey matter of the spinal cord?
- central canal
- posterior horns
- anterior horns
- lateral horns
- Gray commisure
What is the central canal?
small opening in the center of SC, contains CSF
What are the posterior horns?
cell bodies of somatic and visceral (autonomic) sensory neurons
What are the anterior horns?
cell bodies of somatic motor neurons
What are the lateral horns?
cell bodies of autonomic (visceral) motor neurons
- only in thoracic, lumbar and sacral regions of spinal cord
Function of the gray commissure?
Connects posterior horns
What makes up the white matter in the spinal cord?
- Anterior white commissure
- Posterior columns
- Lateral Columns
- Anterior Columns
Function of the anterior white commissure?
connects the white matter on the left and right side of SC
What is the posterior column?
sensory tract (ascending)
What is the lateral column?
motor and sensory tract
What is the anterior column?
motor tract (descending)
What do sensory nerves do?
PNS -> CNS (ascend)
- afferent neurons
What do motor neurons do?
CNS -> PNS (descend)
- efferent neurons
What does somatic mean?
voluntary
What does autonomic (or visceral) mean?
involuntary
What makes up the input and output of the spinal cord?
- Dorsal (posterior) root of spinal nerve
- dorsal root ganglion
- ventral (anterior) root
- spinal nerves
Purpose of dorsal root of spinal nerve
Carries sensory (afferent) information into CNS
What is the dorsal root ganglion
cluster of sensory cell bodies in PNS
Purpose of the ventral root
Carries motor (efferent) neurons info PNS from anterior part of SC
Purpose of the spinal nerves
location of sensory and motor nerves.. pt where they all come together
Are sensory tracts ascending or descending?
Ascending
Are motor tracts ascending or descending?
Descending
