N3: brainstem and blood supply Flashcards
functions of brainstem
- Conduit for tracts (sensory and motor)
- Consciousness, cardiovascular (CV) system, respiratory system, pain perception (reticular formation)
structure of brainstem
- Midbrain
- Pons
- Medulla oblongata
superior colliculi structure and function
bumpy top
part of visual pathway
inferior colliculi structure and function
bumpy bottom
auditory pathway
gracile tubercle structure and function
midline of brainstem
lower limb fibres
cuneate tubercle structure and function
lateral brainstem
upper limb fibres
where is the bulbo-pontine sulcus
between pons and medulla
what lies in the bacilla sulcus
basilla artery
where is the anterior median sulcus
between pyramids
where are the olives
lateral to pyramids
what is the decussation of pyrimidal tracts
where the tracts cross over
in a horizontal section, what are the eyes and mouth of the pug
red nuclei = eyes
cerebral aquiduct = mouth
cause and symptoms of parkinson’s disease
- Characterised by resting tremor, difficulty in initiating voluntary movement and jerking
- caused by depletion of dopamine in substantia nigra
where do afferent neurones enter the spinal cord
dorsal horn
where do efferent neurones exit the spinal cord
ventral horn
function of white matter tracts
→ carry info to and from cerebrum
what is the corticospinal tract
DESCENDING
- pyramidal tract
- voluntary control over skeletal muscles below the head and neck
- decussates at pyramids of medulla
- lateral and anteruir
what is the corticobulbar tract
DESCENDING
- Voluntary (conscious) control over skeletal muscles of head and neck
- precentral gyrus -> internal capsule -> midbrain synapse -> brainstem synapse
what is the dorsal column medial lemniscus tract?
ASCENDING
- relays sensory info from peripheral nerves to cerebral cortex
- proprioception, fine touch and vibration
- signals from gracile nucleus and cuneate nucleus
where do signals from gracile nucleus come from?
lower limb
= medial part of dorsal column
where do signals from cuneate nucleus come from?
from lower limb
lateral part of dorsal column
what is the spinothalamic tract
- Sensory information from the peripheral nerves to the cerebral cortex
- pain, temperature, crude touch and pressure
pathway of DCML
1st: dorsal root ganglion -> nucleus gracilis/cuneate
2nd: nucleus -> thalamus
3rd: thalamus -> post-central gyrus
pathway of spinothalamic tract
1st: dorsal horn -> spinal cord
2nd: SC -> thalamus
3rd: thalamus -> post-central gyrus
what are spinocerebellar tracts
- Unconscious proprioceptive information
- Co-ordinate and refine motor movements
- Signals from muscles to cerebellum
what systems make up the cerebral arterial circle
- Internal carotid system
- Vertebral-basilar system
contents of cerebral arterial circle
- Two internal carotid arteries
- Two vertebral arteries
connect to form circle
where do carotid arteries enter skull
through carotid canal
where do vertebral arteries enter skull
through the foramen magnum
what does internal carotid artery arise from
common carotid artery on arch of aorta
where does vertebral artery originate
subclavian artery
what artery supplies the lateral lobes
medial artery
what artery supplies the anterior lobes
anterior artery
what artery supplies the posterior lobes
posterior artery
what is a Saccular (berry) Aneurysm
- most common type
- occurs within the vessels that supply the cerebral arterial circle
- rupture causes accumulation of blood in the subarachnoid space with a subsequent increase in intracranial pressure.
major dural venous sinuses
- Superior sagittal sinus
- Inferior sagittal sinus
- Straight sinus
- Transverse sinus
- Confluence of sinuses
- cavernous sinus
- sigmoid sinus
what vein do all venous sinuses drain into
internal jugular vein
what are the motor pathways
= descending
corticospinal tract
corticobulbar
what are the sensory pathways
= ascending
spinothalamic tract
dorsal column medial limniscus
