Anatomy 20 (Neuro 3) Flashcards
What is the midbrain divided into?
Dorsal tectum
Ventral tegmentum
What is the bulbopontine sulcus?
A transverse groove at the caudal border of the pons
What is the basilar sulcus?
A shallow sulcus in which the basilar artery runs
What are the middle cerebellar peduncles
Lateral extensions of neural tissue from the pons to the cerebellum
What is the anterior median fissure?
a partial division of the medulla in the ventral
midline
What is the inferior cerebellar peduncle?
Forms the posterolateral margin of the medulla, a thick bundle of white matter passing into the cerebellum.
What is the tectum made up of?
Colliculi
What is the superior colliculi part of?
Visual system, concerned with visual reflexes
What is the inferior colliculi part of?
Auditory system, concerned with the reflex of
looking towards a loud noise
What is the superior cerebellar peduncle?
A fibre bundle passing from the cerebellum to the midbrain
What is the pineal gland?
An endocrine gland that synthesises melatonin which modulates sleep patterns in both circadian and seasonal cycles
What is the function of the inferior brachium?
Conveys auditory information from the medial geniculate body (nucleus) to the inferior colliculi
What is the function of the superior brachium?
Conveys visual information from the lateral geniculate
body (nucleus) to the superior colliculi
What does the tegmentum in the pons contain?
Contains the nuclei of the:
Abducens (Cn 6),
Facial (Cn 7)
Trigeminal (Cn 5 [motor division - muscles of mastication])
What does the posterior median sulcus mark?
The midline of the medulla
What is the gracile tubercle?
Round swelling on either side of the midline, overlying the gracile fasciculus
What is the function of the gracile fasciculus?
Carries fine touch, vibration, two-point discrimination
and proprioception from the lower limb
What is the cuneate tubercle?
A swelling lateral to the gracile tubercles, overlying the cuneate fasciculus
What is the function of the cuneate fasciculus?
Carries fine touch, vibration, two-point discrimination
and proprioception from the upper limb
What does the tegmentum in the medulla contain?
Contains the nuclei of the:
Glossopharyngeal (Cn 9)
Vagus (Cn 10)
Accessory (Cn 11)
Hypoglossal (Cn 12)
What is the dorsal column nuclei?
A major relay site for the dorsal column sensory pathway
What is Bell’s palsy?
Acute unilateral inflammation of the facial nerve (lower motor neurone)
What is Bell’s palsy caused by?
Herpes zoster (virus that also causes shingles), a vesicular rash is present in the external auditory canal and on the oropharynx
What are signs and symptoms of Bell’s Palsy?
▪ Pain behind the ear.
▪ Paralysis of facial muscles and failure to close eye.
▪ Absent corneal reflex.
▪ Hyperacusis (certain sounds heard as unpleasantly loud).
▪ Loss of taste on anterior two-thirds of tongue.
What is Bulbar palsy?
Impairment of the functions of the cranial nerves that arise from the medulla (Cn 9, 10, 11 and 12)
What are signs and symptoms of Bulbar Palsy?
▪ Dysphagia (difficulty swallowing).
▪ Dysarthria (slurring of speech).
▪ Dysphonia (difficulty forming sounds).
▪ Sialorrhea (excess saliva / dribbling).
▪ Wasting and fasciculating tongue.
▪ Absent gag reflex.
What are causes of Bulbar Palsy?
Motor neurone disease (MND)
Amyotrophic lateral sclerosis (ALS)
Guillain-Barré syndrome
What is central pontine myelinolysis?
Destruction of myelin in the pons
What are signs and symptoms of central pontine myelinolysis?
▪ Confusion.
▪ Balance problems.
▪ Dysphagia.
▪ Hallucinations.
▪ Reduced consciousness.
▪ Slurred speech.
▪ Tremor and weakness in the face or limbs
When does central pontine myelinolysis occur?
When low sodium levels (hyponatremia) are corrected too quickly
What is the mnemonic for the geniculate bodies?
MALE
Medial geniculate for Auditory system
Lateral geniculate for Visual System (Eyes)
What is the function of the optic nerve?
Carries the axons of the cells in the ganglionic layer of the retina
Where does the optic nerve enter the skull?
Through the optic canal
Where do the fibres from the nasal portion of the retina cross at?
Optic Chiasm
Where is the optic chiasm located?
Anterior to the pituitary infundibulum
Where do the optic tracts carry the fibres from the nasal portion of the retina?
Carry the fibres posterolaterally round the cerebral peduncles to terminate at the lateral geniculate bodies of the
thalamus
Where do the axons of the nerve cells from the lateral geniculate pathways pass?
Pass posteriorly through the internal capsule to the visual cortex of the occipital lobe
What does a pituitary tumour cause?
Causing under- or overproduction of hormones and
may lead to bitemporal hemianopia due to pressing on the optic chiasm where nerve fibres from both optic nerves cross
What is bitemporal hemianopia?
Impaired peripheral vision in the outer temporal halves of the visual field of each eye
