Neurosensory Physiology Flashcards
Middle cranial fossa
Posterior Cranial Fossa
General anatomy of cerebellum
General anatomy of brain stem
How is the spinal chord protected?
- Wall of the vertebra
- Epidural space
- Duramater - thick and strong, dense irregular tissue
- Subdural space - contains interstitial fluid
- Arachnoid mater - Avascular, thin, elastic and cartilage
- Sub arachnoid space - Full of CSF fluid
- Pia mater - blood supply, thin and transparent
• Denticulate ligaments - thickening of pia mater extending to arachnoid and dura mater.
Protects spinal chord against sudden displacement
Oragnisation of nerves
Dorsal root (posterior) - contains sensory neurons from sensory receptors
Dorsal ramus - supplies posterior surface skin such as deep muscles of back
Anterior ventral root - motor axons conduct nerve impulses to effector muscles
Anterior ramus - Supplies anterior, lateral surfaces as well as upper and lower limbs
Protection of nerves
Endonierium - indivisual axons
Fascicles - Perineureum
Outermost layer - Epineurium
Parasympathetic nerve
- Long pre ganglionic fibres
- Ganglion within or adjacent to target organ
- Short post ganglionic fibres
Sympathetic nerve
- Short pre ganglionic nerve
- Synapse in sympathetc chain
- Long post ganglionic neuron straight to effector organ
except for splanchnic nerves
Splanchnic nerve
- Pre ganglionic neuron pass through the sumpathetic chain without synapsing
- Synapse in seperate collateral ganglia
Supplies abdomino visecera with sympathetic innervation
Medulla Oblongata
- Contains all ascending and descending spinal tracts between the spinal chord and brain
- Most inferior part of the brain stem
- Medullary pyramids - left & right, bulges of white matter anteriorly formed by corticospinal tract
- Medullary olive - Just lateral to each pyramid and an oval shaped swelling
- regulates muscle activity by regulating activity of cerebellar neurons
Pons
• Directly above the medulla oblongata
- Ventral region
• Pontine nuclei - white matter tracts between the cortex of one cerebral hemisphere to the opposite
- coordinates and maximises efficency of voluntary motor output
- Dorsal region
• Contains pontine resp centre
Mid brain
ANTERIOR - CEREBRAL PEDUNCLES
-paired bundls of axons from cerebral cortex to spinal chord
MIDDLE - CEREBRAL AQUEDUCT
- passes via the third ventricle to fourth ventricle
POSTERIOR -TECTUM
- • ( 2x) Superior colliculi - reflex centre for visual activity
- • Inferior colliculi (2x) - part of auditory pathways
Dorsal column - Medial leminiscus pathway
• First order neurone
- Signals from T6 above
- Travel in fasiculis cuneatus ( lateral part of dorsal column)
- Synapse in nucleus cuneatus in medulla oblongata
- Signals below T6
- Travel in fasiculus gracilis (medial part of dorsal column)
- Synapse in nucleus gracilis in medulla oblongata
• Second order neurone
- Axons decussate in medulla oblongata
- Travel via contralateral medial leminiscus pathway to synapse thalamus
• Third order neurone
- transmit sensory signals from thalamus to ipsilateral primary sensory cortex via internal capsule
Ascending tracts
Sensory information from peripheral nerves to the cerebral cortex
- Dorsal column medial leminiscus - fine touch, vibration and proprioception
- Anterolateral system
- Anterior spinothalmic tract - crude touch and pressure
- Lateral spinothalmic tract - pain and temperature