Neuroantamony 2 Flashcards
What is the function of the optic chiasma ?
2 optic nerve converge here
Hemidecussation of the optic fibres to project to the lateral geniculate nucleus
It is the nasal portions which decussate to the contralateral side
Temporal portions remain ipsilateral
Hypothalamus is above and pituitary gland is below
What is the function of the olfactory bulb ?
Main relay station in the olfactory pathways
Where the initial processing of olfactory info occurs
Contains many interneurons
What is the function of the mammillary bodies ?
Part of the lambic system
Receives afferents neurons from hippocampus and send projections to anterior nucleus of thalamus and brainstem
What is the function of the superior colliculus?
Input via tectospinal fibres is reflex in nature and causes closure of eyelids in response to intense light or rapid approaching object
Tectospinal fibres originate here
What is the function of the periaqueductal grey ?
Important in descending control of pain pathways
Involved in vocalisation, control of reproductive behaviour, modulation of medullary respiratory centres, aggressive behaviour and vertical gaze
Receives info from bladder filling and so is involved in process of micturition
What is the function of the inferior olive ?
Thought to be involved in motor coordination and motor learning due to its connections to the cerebellum
What is the function of the raphe nucleus ?
Many of the neurons are serotonergic
Many fibres distributed throughout CNS
- ascending fibres to forebrain are involved in sleep
- descending fibres to spinal cord involved in modulation of pain
What is the function of the red nucleus ?
Involved in motor control
Rubrospinal tract originates here and is involved in toning of limb flexor muscles
Receives motor info from cerebellum and motor cortex
What is the function of the substantia gelantinosa?
Also known as rexed laminae 1-111
Integrates sensory info to provide the feeling of pain
Receives collateral a of a-delta and c fibres involved in pain
What is the function of the spinothalamic tract ?
Also known as neospinothalamic system
Ascending fibre tract carrying info about pain, temperature and course touch and pressure
What is the function of the corticospinal tract ?
Descending fibre tract originating from neurones in the motor areas of the cerebral cortex
Control activity of motor neurons in spinal cord which innervate trunk and limb muscles
Involved in controlling skilled and voluntary movements
What is the function of the lissauers tract ?
Also known as posterolateral tract
Axons project from dorsal root ganglion carrying info about pain and temp
Axons enter into spinal cord and ascend/descend few spinal segments
Axons end up forming spinothalamic tract
What are the clinical consequences of a thoracic spinal cord hemilesion ?
Brown- Sequard syndrome
- ipsilateral loss of proprioception and upper motor neuron signs
- contralateral loss of pain and temperature
What are the clinical consequences of a unilateral brainstem lesion ?
Ipsilateral cranial nerve dysfunction
Contralateral spastic hemiparesis( paralysis of one side)
Contralateral hemisensory loss
Extensor plantar response/ babinski response
Ipsilateral in coordination
What are the clinical consequences of unilateral Cerebellar hemispheric lesion ?
Ipsilateral in coordination of arm and leg
Unsteady gait in the absence of weakness or sensory loss
Impairs coordination of eye movements causing nystagmus
What are the clinical consequences of cerebral hemispheric lesion ?
Mental impairment (asphasias) Contralateral spastic hemiparesis Hyperreflexia - caused by spinal cord injury t5 or above Extensor plantar reflex Contralateral hemisensory loss
What causes hemiballismus ?
Lesion of subthalamopallidal pathways or the subthalamic nucleus
- causes involuntary violent hyperkinesis of the contralateral upper and lower extremities
What are the causes of subdural haemotoma ?
Caused by tearing of the veins stretching across the subdural space - chronic subdural haemotoma
Blow to the head causing blood vessels along surface of the brain to tear - acute subdural haemotoma
What are the causes of hydrocephalus ?
Obstruction of CSF in the ventricular system - caused by tumour or obstruction of subarachnoid space
Damage to arachnoid villi
Brain can start to produce too much CSF
What are the causes of multiple sclerosis ?
Immune system attacking the myelin sheath of axons
Caused by a combination of genetic and environmental factors - smoking, lack of vitamin D or a virus
What are the causes of upper motor neurone disease ?
Lesions to motor areas of the brain/spinal cord
Haven’t developed properly
Lesion of the corticospinal tract
What are the causes of trigeminal neuralgia ?
Blood vessels compressing the trigeminal nerve
Caused by MS or a tumour
Aberrant sensory roots exist
What are the causes of Bell’s palsy ?
Acute unilateral inflammatory lesion of the facial nerve on its course to the skull
Caused by herpes zoster virus, middle ear infection, Lyme disease and other virus’s
What makes up the lentiform nucleus ?
Putamen
Globus pallidus
What makes up the basal ganglia ?
Globus pallidus
Putamen
Caudate nucleus
What happens to the dorsal column pathways at the medulla ?
The fibres converge at the junction between the closed and open medulla forming the gracilis and cuneatus tubercles
What does the cingulate gurus form into ??
Parahippocampal gurus which turns back on itself forming the uncus
What is the uncus ?
Houses the primary olfactory Cortex
Which part of the medulla has the central canal running through it ?
Closed medulla
Opens up into the 4th ventricle at the obex
What makes up the floor of the 4th ventricle ?
Medulla and pons
What makes up the roof of the 4th ventricle ?
Cerebellum
What are 2 prominent aspects on the dorsal surface of the midbrain ?
Superior and inferior colliculi
What are the cerebral peduncles?
Also known as basis peduncles
- white matter bundles
- carry motor info from the cerebral cortex to the brainstem
What is the interpeduncular fossa?
It’s inbetween the cerebral peduncles
Oculomotor nerve emerges from it
Where does the hypoglossal nerve arise from ?
The junction between the pyramids and the olive
What nerves arise from the Cerebellar pontine angle ?
7, 8, 9
What nerve arises from the medullary/pontine junction ?
6
What is the vermis ?
Runs in the midline of the cerebellum
