B5 CNS: Anatomy of the Sensory Nervous System Flashcards
What are the functions of the sensory nervous system?
Collecting information (stimuli) from internal and external environment Integrating, interpreting and assessing collected information
Which spinal cord root is purely sensory?
Dorsal
What is a ramus in relation to the CNS?
The branching of a spinal nerve after the anterior and posterior roots have combined to form a single nerve
Where does the spinal cord end?
L1-L2
What does the spinal cord taper off into?
Cornus
What structure is responsible for the tapering of the terminal portion of filum?
Pia mater
Where is the white matter on the spinal cord?
Outside region
Is the vagus nerve a cranial nerve?
Yes
What is the point of plexuses?
To redistribute nerves more efficiently
Give an example of a plexus?
C3-C5 (Phrenic nerve)
Brachioplexus- plexus from neck
What is a myotome?
Section of muscle innervated by a spinal nerve
What is a dermotome?
Section of skin innervated by a spinal nerve
With reference to the CNS, what are synonyms for ‘sensory’?
Afferent
Ascending
What is the difference between a fasiculus and a lemniscus?
Nothing
What is the difference between a lemniscus and a peduncle?
Nothing
What are synonyms for ‘tract’?
Fasiculus
Lemniscus
Peduncle
What are tracts?
Bundles of axons
Between white matter and grey matter, where would you expect to find tracts?
White matter
What are ganglia?
Collections of cell bodies
What is the difference between a bipolar and unipolar neuron?
Bipolar - Two axons off of the cell body
Unipolar- One axon attached to a cell body/ One axon that splits into two off the cell body
Where would you find the majority of pyramidal neurons?
CNS
What are the most medial fibres of the dorsal column?
Gracile nucleus
What are the most lateral fibres of the dorsal column?
Cuneate nucleus
Of the nuclei in the dorsal column, which one is responsible for innervating the lower limbs?
Gracile
What are the lateral spinothalamic pathways responsible for?
Pain & Temperature
What are the anterior spinothalamic pathways responsible for?
Crude touch
What tracts are responsible for unconscious perception?
Spinocerebellar
Which tracts are responsible for conscious perception?
Spinothalamic
Dorsal column- medial lemniscus
What lobe of the brain is most concerned with vision?
Occipital
How many sagittal zones does the cerebellum have?
3
How many lobes does the cerebellum have?
3
What are the most anterior bits of the cerebellum?
Flocculus and nodules
What are the little bumps on the cerebellum called?
Folia
How many deep cerebellar nuclei are there?
4
From most lateral to most medial, what is the order of the deep cerebellar nuclei?
DGEF
What are the two nuclei between the dentate and fastigal nuclei collectively known as?
Interpose nuclei
How is the body mapped on the cerebellar hemispheres?
Ipsilaterally
If a patient were to come in with right sided cerebellar problems, which side of their body would be affected?
Right
What roles does the cerebellum have?
Unconscious proprioception
Constant feedback and improvement of movement
Balance
What motor pathway can the cerebellum bypass?
Corticospinal
What nuclei are responsible for the cerebellum being able to bypass a descending pathway?
Tranverse nuclei of pons
Where are sympathetic neurones always found?
Craniosacrally
Where are parasympathetic neurones always found?
Thoracolumbarly
What are splanchnic nerves?
Nerves that act parasympathetic.
What are the properties of thoracic splanchnic nerves?
Pre-gangionic
Tend to run to the gut
Where do the great splanchnic nerves run from?
T5-T9
Where do the lesser splanchnic nerves run from?
T10-T11
Where do the least splanchnic nerves run from?
T12
What are the properties of sympathetic nerves?
Thoracolumbar
Paravertebral + Prevertebral ganglia
Relatively long
What are the properties of parasympathetic nerves?
Craniosacral
Terminal Ganglia
Relatively short
How much longer are the sympathetic post ganglionic neurones in comparison to the pre ganglionic neurones?
17 times longer
How much longer are the parasympathetic post ganglionic neurones in comparison to the pre ganglionic neurones?
Twice as long
What does the sympathetic nervous system innervate?
Virtually everything
What does the parasympathetic nervous system innervate?
Mainly visceral organs
What structures in the nervous system are responsible for mediating reflexes?
Spinal cord
Brainstem medullary centres
List examples of polysynaptic visceral reflexes?
Gastric and Intestinal Swallowing
What is the autonomic innervation of the bladder?
Balance between sympathetic and parasympathetic supply
Sympathetic supply to parasympathetic endings turns off parasympathetics
What controls whether sympathetic presynaptic ganglions inhibit parasympathetic endings?
Urination centre in pons
