other past qs

Question 1

describe lesions of facial nerve

Answer 1

• Chorda tympani(GVE - submandibular ganglion and pterygopalantine ganglion + SVA - anterior 2/3 of tongue) – reduced salivation and loss of taste on the ipsilateral 2/3 of the tongue.
  Nerve to stapedius– ipsilateral hyperacusis (hypersensitive to sound).
  Greater petrosal nerve(combine with deep petrosal nerve to form nerve of pterygoid/vidian canal, innervate nose, pharynx, mucous membrane of oral cavity and lacrimal gland)– ipsilateral reduced lacrimal fluid production
  *UMN - lower face is paralysed forehead is function
  LMN - hemiparalysis - bell’s palsy

Question 2

describe path of CSF

Answer 2

CSF bathes and cushions the brain and spinal cord within their bony confines.
- Cerebrospinal fluid produced by modified ependymal cells of choroid plexus.
- CSF flows from lateral ventricles via foramina of Monro/ inter ventricular foramen into the third ventricle, and then the fourth ventricle via the cerebral aqueduct in the brainstem.
- CSF passes into central canal of spinal cord or into cisterns of subarachnoid space via three small foramina: the central foramen of Magendie and the two lateral foramina of Luschka.
- CSF flows around the superior sagittal sinus, is reabsorbed via the arachnoid villi into the venous system.
- CSF within spinal cord can flow all the way down to the lumbar cistern at the end of the cord around the cauda equina where lumbar punctures are performed.
- Cerebrospinal fluid can be analysed to make judgments about a person’s general health. A sample is taken from the spinal cord via a lumbar puncture
Cerebral acqueduct between the third and fourth ventricles very small, if blocked, leads to high pressure in the lateral ventricles

Question 3

Describe lesions of trigeminal nerve

Answer 3

• Neuralgia - type of trigeminal neuropathy brought on by nerve damage
• Primary trigeminal neuralgiaoccurs when an artery or vein wraps around the trigeminal nerve and causes irritation.
• Secondary trigeminal neuralgiaoccurs when a tumor, cyst or facial injury puts pressure on the trigeminal nerve.Multiple sclerosisalso causes a form of secondary trigeminal neuralgia.

Question 4

describe test you would conduct for potential trigeminal branch ophthalmic nerve

Answer 4

Corneal reflex - protection mechanism of the eye place thinned cotton balled infant of eye to see if eye responds fast enough to stimulus
Orbicularis fris is stimulated
Gently touch cornea- ophthalmic nerve - spinal nucleus of trigeminal nerve - motor nucleus of facial nerve - orbiculares oris contracts

Question 5

describe pathway of lateral reticulospinal tract

Answer 5

• originate medullary reticular formation
  Start cerebral-reticular fibres in inhibitory cortical area in precentral gyrus
  Synapse internuncial neurones or directly with anterior horn cells that act on Gamma efferent system.
  Putamen receives fibres from cerebral cortex, Substantia Nigra and Caudate nucleus
  Efferent from caudate nucleus, putamen, substantia nigra, thalamus pass through globus pallidus
  Globus pallidus is main outflow for corpus striatum
  Efferent fibres descend in ansa and fasiculus lenticular is and go through medial side of internal capsule
  Descend to reticular nuclei in medulla and pons
  Some fibres turn upward to fasiculus thalamicus and end in ventral anterior nucleus of thalamus
  Rest descend to sub thalamic nuclei , red nucleus and reticular nuclei of medulla
  facilitatory reticulospinal fibres descend to lateral column and end in anterior horn cell
  Activate alpha and gamma motor neurons

Question 6

list and describe types of brain haemorrhages

Answer 6

Extradural haemorrhage- between dura and skull. = lemon shaped
Subdural haemorrhage - between arachnoid mater and dura mater = crescent or moon shaped
Subarachnoid haemorrhage - in subarachnoid space between arachnoid mater and Pia mater

Question 7

describe both hernias

Answer 7

Uncus herniation = Uncus of the temporal lobe can be pushed through the tentorial notch. This presses on III, particularly the efferent parasympathetic fibres, causing a sluggish light reflex
Cerebellar tonsil herniation = Cerebellar tonsil can be pushed into the foramen magnum, pressing on the medulla and abnormal function of the cardiorespiratory centre causes: • BP to rise • pulse rate to fall • cycles of apnoea and tachypnea/hyperventilation à Cheyne-Stokes respiration