Nervous System 3 Flashcards
Summarize the meninges of the spinal cord
Continuous with cranial meninges
- Dura mater
- tough mother
- thick outer layer
- Continuous with cranial dura & epineureum
- Dural sac extends to 2nd sacral vertebrae
- Arachnoid mater
- middle layer
- continuous with arachnoid of brain
- Pia mater
- thin inner layer
- adheres to surface of brain & spinal cord
- denticulate ligament
- triangular extensions
- suspend spinal cord in the dural sheath
What are the CNS spaces?
Epidural space-
- between wall of vertebral canal & dura
- contains fat & connective tissue
Subdue also space
- between dura & arachnoid
- contains interstitial fluid
Subarachnoid space
- Between arachnoid & pia
- contains cerebral spinal fluid(CSF)
Describe the dimensions of the spinal cord?
Extends from medulla oblangata to 2nd lumbar vertebra in adults
-3rd to 4th lumbar vertebra in infants
42-45cm (16- 18 in.)
What are the regions of the spinal cord ?
- Cervical
- Thoracic
- Lumbar
- Sacral
- Coccygeal
What is the cauda equina?
Roots of lumbar, sacral & coccygeal nerves
What is the filum terminale?
- extension of pia mater
- anchors spinal cord to coccyx
What is the conus medullaris?
- termination of spinal cord
- level of intervertebral disc of L1-L2 in adults
Where is the lumbar enlargement?
T9 to T12
Where. Is the cervical enlargem3nt?
C4 to T1
How many pairs of spinal nerves are there?
31 pairs-mixed nerves
How is a lumbar puncture done?
Hollow needle inserted into the subarachnoid space
- withdrawal of CSF - diagnostic - Delivery of anesthetics
L3-L4 or L4-L5
Describe the gray matter of the spinal cord
Anterior horn
-somatic motor neurons
Posterior horn
-interneuron & axons of incoming sensory neurons
Lateral horn
-Autonomic motor neurons
Describe the white matter of the spinal cord
- Anterior white column
- Posterior white column
- Lateral white column
Describe the tracts of the spinal cord
Each column contains distinct bundles of axons
- Sensory tracts
- Acsending
- Motor tracts
- Descending
What are the distinguishing characteristics of the cervical segment of the spinal cord?
Relatively large diameter, relatively large amounts of white matter, oval in shape; in upper cervical segments (C1-C4), posterior gray horn is large, but anterior gray horn is relatively small; in lower cervical segments(C5 and below), posterior gray horns are enlarged and anterior gray horns are well-developed
What are the distinguishing characteristics of thoracic segments of the spinal cords?
Small diameter is due to relatively small amounts of gray matter; except for first thoracic segment, anterior and posterior gray horns are relatively small; a small lateral gray horn is present