Spinal Cord - Chapter 14 Flashcards
What are the four major functions of the spinal cord?
- Conduction - sensory signals from body to brain, motor signals from brain to muscles/glands
- Neural Integration - pools of neurons integrate signals from various sources and execute an appropriate output
- Locomotion - pools of spinal neurons control movement
- Reflexes - control posture, motor coordination, and protection from injury
Where (specifically) is the spinal cord located?
From the Foramen Magnum (of the skull) to the 1st/2nd lumbar vertebrae
(Upper 2/3 of vertebral canal)
How many pairs of spinal nerves are there?
31 pairs of MIXED spinal nerves
Where is the spinal cord the widest? What are the four regions? What is considered a segment?
Widest at bottom (widens inferiorly)
Four regions: cervical, thoracic, lumbar, and sacral/coccygeal
A segment is a part of the spinal cord supplied by each pair of spinal nerves
What are the longitudinal grooves on the anterior and posterior sides called?
- anterior median fissure
2. posterior median sulcus
What two areas of the cord are thicker than elsewhere? Why?
- Cervical enlargement - supplies nerves to upper limb
2. Lumbar (lumbosacral) enlargement - supplies nerves to pelvic region and lower limbs
What is the medullary cone?
Where the cord tapers to a point inferior to lumbar enlargement
What is the cauda equina?
Bundle of nerve roots that occupy the vertebral canal from L2 to S5
What is the filum terminale (hit: associated with the cauda equina)
A thin strand of Pia mater that attaches the conus medullar is to the coccyx
What are the three spinal meninges?
- Dura Mater (outermost)
- Arachnoid mater (middle)
- Pia mater (innermost)
Describe the dura mater of the spinal cord and what it does
Dural sheath surrounding the spinal cord
Separated from vertebrae via periosteum (this is where they put epidermal anesthesia)
Provides the stability in the meningeal layers
Describe the arachnoid mater of the spinal cord and what it does
Membrane adheres to dura
Separated from Pia by fibers in the subarachnoid space (filled with CSF, where you take a spinal tap from)
Describe the Pia mater of the spinal cord and what it does
Delicate membrane, follows contours of CNS
Transparent, past medially cone - terminal filum
Describe the grey matter of the spinal cord. Is it the stuff on the inside or outside?
Neuron cell bodies with little to no myelin
Neurosomas, dendrites, proximal axon
Site of information processing, synaptic integration
Stuff on the inside (butterfly/H-shaped)
Describe the white matter of the spinal cord. Is it the stuff on the inside or outside?
Myelinated axons
Carry signals from one part of CNS to next
Stuff on the outside
Describe the (4) different features/landmarks in the grey matter of the spinal cord
- Posterior (dorsal) horns - receive sensory info, cell bodies of interneurons
- Anterior (ventral) horns - somas of motor neurons
- Gray commissure - connects right and left side, central canal lined with ependymal cells (filled with CSF)
- Lateral horn - visible from T2 through L1, neurons of sympathies nervous system
Describe the 3 funiculi/columns in the white matter of the spinal cord
Bundles of axons up and down the spinal cord Communicate between levels fo the CNS Surround grey matter 3 pairs of bundles: 1. Posterior column 2. Lateral column 3. Anterior column
What are the subdivisions of the funiculi/columns in white matter of the spinal cord called?
Ascending tracts (take sensory info TO higher levels of cord and brain) Descending tracts (take motor signals FROM brain to motor neurons that control muscles and glands)
What is decussation?
Cross over from one side to the other
Ex: left side of brain controls right side of the body
What’s the difference in contralateral and ipsilateral?
Contralateral - origin and destination on opposite side of body
Ipsilateral - origin and destination on same side of body
