white vs grey matter
- White matter
- myelinated axons, signal transmission up and down - Grey matter:
- cell bodies and processing centers
- function is to integrate and process information
- the inner butterfly shape
what is the posterior median sulcus? what is the conus medullaris?
- the posterior median sulcus is the back groove
- the conus medullaris is the end of the spinal cord at L1-L2 (cone shaped)
what is the cauda equina and filum terminale?
the cauda equina:
Extended anterior and posterior roots of spinal segments L2
to S5 and filum terminale
– Name comes from resemblance to a horse’s tail
- filum terminale is the strand of fibrous tissue from tip of conus medullaris to S2 and provides longitudinal support to spinal cord
how are c1-c7 orientated? how is c8 and below orientated in relation to their vertebra?
Rules for naming spinal nerves
From C1-C7 the nerves are above the vertebra
C8 is below, and all the others are below (like T1 is below 1st thoracic vertebra)
what is the difference between the anterior and posterior root?
The anterior root is the ventral root which contains motor neuron axons and carriers signals OUT of the CNS (think anterior as out)
The posterior root is the dorsal root which contains sensory neuron axons and carries information INTO the CNS (dorsal is the back door into the party)
true or false: the posterior root ganglion contains cell bodies of motor neurons in the posterior root
FALSE!! the posterior root ganglion contains cell bodies of SENSORY NEURONS in the posterior root!!
what are the spinal cord meninges function?
The spinal cord meninges provide physical stability, shock absorption, and carry blood supply (oxygen and nutrients)
what is the epidural space and subarachnoid space
- epidural space is where injections are done so there’s no pain felt - a fatty layer
- subarachnoid space contains CSF
what is lumbar puncture procedure? wheres it done and why there?
Lumbar puncture procedure
- extract fluid from subarachnoid space in the lumber region and its done there to avoid damaging spinal cord
sensory nuclei vs motor nuclei
Sensory nuclei receive and relay sensory information from peripheral sensors (recieve and process info)
Motor nuclei issue motor commands to peripheral effectors (send commands to muscles and glands)
what are posterior gray horns?
Posterior gray horns contain somatic and visceral sensory nuclei
- its function is to receive sensory input and relay info
what are anterior grey horns?
Anterior gray horns contains SOMATIC motor nuclei and its function is to send motor commands to muscles
what are lateral gray horns?
Lateral gray horns are only in thoracic and lumbar regions and contains visceral motor nuclei
true or false: a damaged locaiton of the grey mmatter can predict which muscle is affected and which function is lost
true! Spinal cord is highly organized and each region controls specific functions
Damage location predicts which muscle is affected and wich function is lost
what are asending and desending tracts in the spinal cord?
Its organized into tracts and carry information
- the ascending tracts go to sensory to the brain (posterior white column)
The descending tracts go to motor neurons which are from the brain (anterior white column)
What are spinal nerves made of and what are their connective tissue layers? (hint three layers)
Spinal nerves are mixed (contain both sensory + motor neurons)
Formed by merging:
Posterior root (sensory)
Anterior root (motor)
Connective tissue layers:
Epineurium: outer layer of entire nerve
Perineurium: surrounds fascicles (bundles of axons)
Endoneurium: wraps individual axons (not fascicles)
each spinal nerve splits into TWO rami and each supply:
Each spinal nerve splits into two rami:
1. Posterior ramus which supplies the muscles, joints, and skin of back
2. Anterior ramus which supplies the anterior and lateral trunk and the limbs
how does rami communicate?
Rami communicates and is found in T1-L2 and carries sympathetic motor signals
- its part of the autonomic nervous system in response to fight or flight
what does commissure mean?
commisure is when theres is a right side linekd to the left side
what are dermatomes?
Dermatomes is area of skin that is supplied by a single spinal nerve
- it’s used to diagnose nerve damage. For example, shingles follows dermatomes
what are nerve plexuses? what are the four major ones?
Nerve plexuses is a network of interwoven nerves found by ventral (anterior) Rami
There are four major plexuses
1. Cervical plexus –> C1-C5
2. Brachial plexus –> C5-T1
3. Lumbar plexus –> 512-L4
4. Sacral plexus –> L4 –> S4
what are thei mportant nerves to know?
It’s important to know these nerves:
- phrenic nerve → breathing
- radial nerve → radial bone in arm
- ulnar nerve → medially located
- median nerve
- femoral nerve
- sciatic nerve → in the back but you feel sharp pain in your butt
- saphenous nerve
what contains fissure, gyri, and sulci?
cerebrum contains fissure, which seperate right and left hemispheres, gyri is bumps, and sulci is grooves
what are the three cranial meninges?
Dura mater → fused with the periosteum of cranial bones, no epidural space in brain
(two layers which is seperated by dural venous sinus)
Arachnoid mater → web like layer, does not follow brain folds, and has trabeculae across subarachnoid spaces
Pia mater → thin layer, directly adheres to brain surface
