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04
Spinal Cord and Hindbrain
45
Pharmacology
Undergraduate 1
12/27/2016

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Cards

Term
Why do the cervical and lumbar regions of the spinal cord enlarge?
Definition
these areas deal with innervation of the arms (cervical) and legs (lumbar). There is a larger mass of nerve cells bodies and tracts to accomadate the innervation needs of the limbs.
Term
How many spinal nerves are there?
Definition
Spinal nerves (31 segmental pairs) exit via gaps between vertebrae – the intervertebral foraminae.
Term
Do spinal segments and vertebra align?
Definition
Spinal segments and vertebra do not align exactly. The spinal segments are specified by the level of vertebrae at which the spinal nerve exits the spinal column.
Term
Define white matter
Definition
regions of the CNS that are dominated by myelinated axons of ascending or descending tracts.
Term
Define grey matter
Definition
areas in the CNS that are dominated by neurone cell bodies, neuroglia, unmyelinated axons and afferent terminals.
Term
When does the ventral horn enlarge?
Definition
at segments that control the limbs - motor neurones are large and numerous.
Term
How can cervical be differentiated from lumbar?
Definition
shape: cervical is wide and squashed whereas lumbar are round
white matter: the amount of white matter relative to grey matter decreases as you go down
Term
What are the rexed laminae?
Definition
a system of ten layers of grey matter (I-X) identified in the early 1950s by Bror Rexed to label portions of the spinal cord.
Term
What lamina exist in the dorsal horn?
Definition
Lamina I-V
Term
Describe lamina I
Definition
'nucleus' posteromorginalis' contains neurones tat receive pain and temperature information from dorsal root gangly
Term
Describe lamina II
Definition
'substance gelatinosa' painful and non-painful information fro spinothalamic tract and relays to lamina III
Term
Describe lamina III, IV and V
Definition
'nucleus proprius' information about touch and proprioception and relays to brainstem/brain/lamina
Term
What lamina exist in the intermediate horn?
Definition
lamina VII
Term
Describe lamina VII
Definition
'intermediolateral nucleus' mediates the entire sympathetic innervation of the body
Term
What lamina exist in the ventral horn?
Definition
lamina IX
Term
Describe lamina IX
Definition
motor neurones that innervate muscles
Term
What are the spinal meninges?
Definition
a series of specialised membranes surrounding the spinal cord, provide the necessary physical stability and shock absorption.
Term
Describe the 3 meninges layers
Definition
1. Dura mater: thickest outer most layer.
2. Arachnoid mater: adheres to the inner surface of the dura mater.
3. Pia mater: intimately bound to the surface of the spinal cord.
Term
What is the subarachnoid space filled with?
Definition
cerebrospinal fluid (CSF) which is continuous with the brain.
Term
What information enters the spinal cord?
Definition
sensory information via general somatic/visceral afferents that enter at the dorsal posterior root
Term
What resides in the dorsal root ganglion?
Definition
cell bodies of afferent neurones
Term
What do interneurones do?
Definition
link sensory neurones with motor or autonomic neurones
Term
What information leaves the spinal cord?
Definition
somatic motor outflow
motor efferents innervating peripheral striated muscle exit via the ventral (anterior) root
Term
Describe pre-ganglionic neurones in the ANS
Definition
Visceral motor neurones in the brainstem and spinal cord are known as preganglionic neurones because they extend towards ganglia. These neurones are part of visceral reflex arcs; most of their activities represent direct reflex responses, rather than responses to commands from the hypothalamus. The axons of preganglionic neurones are called preganglionic fibres. Preganglionic neurones leave the CNS and synapse on ganglionic neurones
Term
Describe ganglionic neurones in the ANS
Definition
anglionic neurones – visceral motor neurones in peripheral ganglia. These ganglia are called autonomic ganglia. Ganglionic neurones innervate visceral effectors such as smooth muscle, glands, cardiac muscle and adipose tissue. The axons of postganglionic neurones are called postganglionic fibres, because they begin at autonomic ganglia and extend to peripheral target organs.
Term
Describe the neurones in the sympathetic division of the ANS
Definition
cell bodies of preganglionic neurones lie within the lateral horn of the spinal grey matter. Preganglionic neurones synapse with postganglionic neurones whose cell bodies reside within the sympathetic chain that runs alongside the spinal cord.
Term
Describe the neurones in the parasympathetic division of the ANS
Definition
cell bodies of preganglionic neurones lie within the brainstem. Preganglionic neurones synapse with postganglionic neurones whose cell bodies reside close to or within target tissues.
Term
How is white matter divided?
Definition
1. Posterior funiculus: this area of the spinal cord includes the dorsal columns.
2. Lateral funiculus: this area of the spinal cord is the most lateral of the bundles.
3. Anterior funiculus: this area of the spinal cord is anterior to the anterior grey horn.
Term
Define syringomyelia
Definition
is a generic term referring to a disorder in which a cyst or cavity forms within the spinal cord.

This cyst, called a syrinx, can expand and elongate over time, destroying the spinal cord. The damage may result in pain, paralysis, weakness, and stiffness in the back, shoulders, and extremities. Syringomyelia may also cause a loss of the ability to feel extremes of hot or cold, especially in the hands. The disorder generally leads to a cape-like loss of pain and temperature sensation along the back and arms.
Term
What is Brown-Sequard syndrome?
Definition
a loss of sensation and motor function (paralysis and anaesthesia) that is caused by the lateral hemisection (cutting) of the spinal cord.
- Loss of pain and temperature from contralateral side of spinal cord damage.
- Loss of touch, proprioception, vibration from ipsilateral side of cord damage.
Term
Define Autonomic Dysfunction (Dysautonomia)
Definition
any disease or malfunction of the autonomic nervous system (ANS).
-severe postural hypotension (loss of consciousness)
-incontinence
- impotence
- lateral horn atrophy
Term
Define motor neurone disease
Definition
a debilitating disease with varied etiology (causes), characterised by rapidly progressive weakness, muscle atrophy and fasciculations (involuntary muscle twitch), muscle spasticity, difficulty speaking (dysarthria), difficulty swallowing (dysphagia), and difficulty breathing (dyspnea).
Term
What makes up the hindbrain?
Definition
the medulla oblongata (the myelencephalon) and the pons (metencephalon).
Term
What makes up the brainstem?
Definition
hindbrain and the midbrain
Term
What is Wallenbergs syndrome?
Definition
thrombosis of vertebral artery
wide ranging sensory/motor deficits
Term
What are the deficits caused by Wallenbergs syndrome?
Definition
1. contralateral loss of pain and temperature sensitivity (anterolateral system: an ascending pathway that conveys pain, temperature and crude touch from the periphery to the brain).
2. ipsilateral loss of pain and temperature sensitivity from face (trigeminal system – nerve V).
3. Vertigo and/or nystagmus: involuntary eye movements from damage to vestibular system.
4. ipsilateral loss of taste from damage to the solitary tract: a compact fibre bundle that extends longitudinally through the posterolateral region of the medulla. It is made up of primary sensory fibres and descending fibres of the vagus, glossopharyngeal, and facial nerves.
5. Dysphagia: difficulty in swallowing due to damage to the ambiguus nucleus in the lateral portion of the rostral medulla. The nucleus gives rise to efferent motor fibres of the glossopharyngeal and vagus nerves.
Term
What is a brainstem glioma?
Definition
a cancerous glioma tumour (so, consisting of glial cells) that arises in the brainstem.
They account for 10-20% of all childhood brain tumours!
Term
Symptoms of a brainstem glioma
Definition
Common presenting symptoms include:
double vision
weakness
unsteady gait: movements of limbs difficulty in swallowing
drowsiness
nausea
vomiting
Term
What are the functions of the ascending system of reticular formation?
Definition
controls arousal, sleep, attention, awareness and wakefulness
Term
What are the functions of the descending system of reticular formation?
Definition
forms reticulo-spinal tract which contributes to posture and postural reflexes
Term
What are the raphe nuclei
Definition
cluster or nuclei found in the brainstem (extend bilaterally rostra-caudally along brainstem adjacent to midline)
uses serotonin as its transmitter
Term
What nuclei make up the raphe nuclei?
Definition
1. nucleus raphe pallidus (within medulla)
2. nucleus raphe obscurus (within medulla)
3. nucleus raphe magnus (within pons)
Term
Describe the medullary nuclei
Definition
project to spinal cord and modulate pain transmission, movement and autonomic control
Term
Describe the rostral nuclei
Definition
project to diverse higher brain areas to modulate pain, mood, sleep-wake cycles
Term
Name some 5-HT disorders and the pharmacological interventions
Definition
depression
TCA (block uptake)
MAO inhibitors (prevent breakdown)
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