Brain and Spinal Cord Flashcards
What is A?
Dentate nucleus
What is B?
Spinal nucleus
What is C?
Tract of trigeminal nerve
What is D?
Medial lemniscus
What is E?
Inferior olivary nucleus
What is F?
Pyramid
What is G?
Pontine nuclei
What is H?
Middle cerebellar peduncle
What is I?
Glossopharyngeal nerve
What is J?
Cochlear nerve
What is K?
Inferior cerebellar peduncle
What are the origin cells of neurons?
Ependymal cells
What are the immune cells of the nervous system?
Microglia
What do olgiodendrocytes do?
Form myelin sheaths in the CNS
What is the function of the pineal gland?
Circadian rhythms
What is the function of the area postrema?
Monitors blood for toxins and triggers the emetic reflex
What are the main functions of dorsal column neurons? Are they ipsilateral or contralateral?
Touch, pressure, vibration, position sense
Ipsilateral in cord
medial lemniscus large fiber pathway
What are the main functions of the anterolateral system small fiber pathway? Is it ipsilateral or contralateral?
Pain and temperature sense
Contralateral
What are the main functions of the corticospinal tract? Is it ipsilateral or contralateral?
Voluntary control of limbs + distal extremities
Ipsilateral
Whats the difference between decussation sites of the dorsal column medial lemniscal system and the anterolateral system?
The dorsal column system decussates in the medulla but is ipsilateral in the spinal cord. The anterolateral system decussates immediately in the spinal cord and is contralateral the whole way.
What is Brown-Sequard syndrome?
A condition that occurs after hemisection of spinal cord. Leads to ipsilateral lose of tactile and limb position sense at lesion level and below (dorsal columns) and contralateral loss of pain and temperature senses a few segments below lesion (anterolateral system).
this occurs because the anterolateral system decussates in the spinal cord a few vertebrae above their starting point
What is Central Cord Syndrome/Syringomyelia?
A syndrome caused by crushing of the cervical region in the center of the spinal cord that affects the anterolateral system (pain and temperature) that leads to reduced pain/temperature sensation in the arms and chest.
What is the central nervous system?
The brain and spinal cord
What is the peripheral nervous system?
Nervous system outside the brain and spinal cord
What is the spinal column?
Bones and ligaments surrounding and protecting the spinal cord
What is the spinal cord?
The cylindrical bundle of nerves made from ascending (sensory info from body to brain) and descending (motor info from brain to body) tracts that is housed within the spinal column from the foramen magnum to the L1 vertebral level
What is the conus medullaris?
Tapered caudal end of spinal cord around L1
What is the cauda equina?
A bundle of spinal nerves and rootlets that arise caudally from the conus medullaris - consists of second through fifth lumbar nerve pairs, first through fifth sacral nerve pairs, and the coccygeal nerve
What is white matter?
Outer area of the spinal cord, appears white due to myelinated axons
What is Gray matter?
Central area of spinal cord with a predominance of cell bodies, shaped like an H or butterfly
What are spinal tracts?
Bundles of nerve fibers organized according to ascending (seonsory) or descending (motor) pathways.
In the picture below, which label represents white matter?
C
D
E
F
Answer: C
In the picture below, which label represents motor nerve fibers?
E
J
F
C
Answer: J
Which spinal cord tract carries motor information from the brain to the peripheral nervous system?
a) spinocerebellar tract
b) spinothalamic tract
c) corticospinal tract
d) dorsal column
c) corticospinal tract
Occlusion of the anterior spinal artery causing anterior cord syndrome would cause damage to which of the following pathways?
a) gracile fasciculus
b) spinocerebellar
c) cuneate fasciculus
d) dorsal column medial leminiscus
b) spinocerebellar
What exits through the intervertebral foramen between the C6 and C7 vertebrae?
a) the C5 cervical spinal nerve
b) the C6 cervical spinal nerve
c) the C7 cervical spinal nerve
d) the C8 cervical spinal nerve
c) the C7 cervical spinal nerve
How many vertebrae are in the vertebral column?
33: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 5 coccygeal
What are the components of the meninges?
Dura + arachnoid + pia mater
Where do nerve roots exit relative to their numbered vertebra?
Thoracic, lumbar, and sacral regions: exit caudally (below) the corresponding vertebra
Cervical: exit rostrally (above) the corresponding vertebra
this is because there is an extra cervical vertebra
What is the function of the nerves in the posterior funiculi?
2 components:
Fasciculi gracilis - sensory information (vibration, deep touch, etc) from the legs to the brain
Fasciculi cuneatus - sensory information (fibration, deep touch, etc) from the arms to the brain
What is the path of decussation for ascending sensory tracts?
They ascend the spinal cord ipsilaterally to their respective nuclei. Then the second-order neurons cross the midline in the caudal medulla. Third motor neurons begin in the thalamus and terminate in the contralateral sensorimotor cortex.
What is the function of the dorsal spinocerebellar tract? Where does it run?
It carries afferent information from muscle spindles and golgi tendon organs to the cerebellum for coordination of grouped muscle movement for postural control and ambulation.
This tract runs with nerves from L3 to C8 in the dorsal portion of the lateral funciculus
What is the path of neurons in the dorsal spinocerebellar tract?
They ascend ipsilaterally to the inferior cerebellar peduncle and terminate in the cerebellar vermis of the anterior lobe.
What is the function of the ventral spinocerebellar tract? Where does it run?
Carries afferent information regarding whole limb movements and postural adjustments to the cerebellum - nerves arise from golgi tendon organs within the muscles.
It runs in the ventral portion of the lateral funiculus
What is the path of nerves of the ventral spinocerebellar tract?
They arise from golgi tendon organs within muscles and synapse in the dorsal root nerve –> sends a second-order neuron n contralaterally to through the medulla to the pons –> joins superior cerebellar peduncle, crosses midline again (now back to ipsilateral) and terminates in the vermis of the cerebellum
What is the function of the spinothalamic tract? What region is it in?
Transmits afferent information about pain, temperature, and nondiscriminative touch to the primary sensory cortex.
It is within the anterolateral funiculus
What is the result of injury to one side of the spinal cord in the spinothalamic pathway?
Contralateral loss pain and temperature sense and tactile stimulation at and below the site of injury
What is the path of the corticospinal tract?
Arises from cerebral cortex –> converges in the corona radiata –> descends through the internal capsule and brainstem –> decussates in the caudal medulla to the contralateral side –> terminates in spinal cord as lateral corticospinal tract
What is the function of the corticospinal tract?
Controlling flexor motor systems and fine motor control of limbs
What is the effect of damage ot the spinocerebellar tract?
Loss of voluntary motor control and flaccid muscle tone at first, and then spasticity and hyperreflexicity
What are the main blood supplies to the spinal cord?
Two posterior spinal arteries, one anterior spinal artery (arises from vertebral arteris and radicular arteries)
Where do the posterior spinal arteries run? What do they supply?
Descend along the posterolateral spinal cord, just medial to dorsal roots.
Supplies the posterior one third of the spinal cord.
Where does the anterior spinal artery go? What does it innervate?
It goes along the midline of the spinal cord.
It supplies the anterior 2/3 of the spinal cord
What is the course of radicular arteries in the spinal cord?
They arise from segmental levels all along the spinal cord and are supplied by the thoracic and abdominal aorta
What is the largest radicular artery? What does it supply?
Artery of Adamkiewicz
It supplies the caudal 2/3 of the spinal cord (with the other small radicular arteries)
Which two areas of the spinal cord are at increased risk of hypoperfusion and infarction?
T1-T4 and L1
Describe venous drainage through the spinal cord.
It is through a series of venous plexuses that empty into the anterior and posterior epidural venus plexuses
What is A?
Lateral corticospinal tract
What is B?
Anterior corticospinal tract
What is 1?
Pyramidal tracts
What is C?
Cuneate fasciculus
What is D?
Gracile fasciculus
What is 2?
Dorsal column medial lemniscus system