session 1 Flashcards
superficial to deep what is the order of the meninges?
dura mater arachnoid mater pia mater
describe the dura mater.
It has 2 layers endosteal which is fused to the periosteum and inner meningeal layer.
how are dural sinuses formed?
-the separation of the endosteal and inner meningeal layers. -these are lined by endothelial cells
what are the 4 points the endosteal and inner menigeal layers separate to form sinuses?
- falx cerebri - divides 2 cerebral hemispheres contains superior and inferior sagital sinuses 2. tentorium cerebelli - separates cerebrum from cerebellum and contains transverse sinus 3. falx cerebelli - separates cerebellar hemispheres 4. diaphragma sella - forms the roof of the pituitary fossa and provides blood supply to the pituitary gland
what makes up the blood brain barrier?
endothelial cells
basement membrane - formed from pia
Astrocytic end feet
what part of the brain does the anterior cerebral artery supply?
medial aspects of the brain and the corpus callosum
what part of the brain does the middle cerebral artery supply?
supplies majority of the lateral surface of the hemispheres
what part of the brain does the posterior cerebral artery supply?
supplies the posterior parts of the brain and the inferior parts of the lateral brain
(yellow)
what are the percentages of blood supplied to the brain by the internal carotids & vertebral arteries?
80% internal carotids and 20% vertebral arteries
what are the most common sites for berry aneurysms?
most common in the anterior communicating arteries
what drains into the straight sinus?
inferior saggital sinus
what drains into the transverse sinus?
superior saggital sinus, ocipital sinus and straight sinus
where does the transverse sinus drain into?
sigmoid sinus
how does venous blood leave the brain?
leaves through the internal jugular through the jugular foramen
what are the three functions of CSF?
- cushioning 2. transport of nutrients 3. supporting - the mass of the brain effectively floats in the skull
how does CSF return back blood?
projections of arachnoid mater goes through the endosteal layer of the dura mater in the superior saggital sinus. these are called arachnoid granulations
what produce CSF? where would you find them?
choroid plexuses on the floor of the lateral ventricles, the roof of the third ventricle and the roof of the fourth ventricle
how does CSF leave the ventricles and enter the sub arachnoid space?
when it reaches the 4th ventricle it can enter the sub arachnoid space through either the lateral (lushke) or median (megendi) aperture
what structures pass through the cavernous sinus?
OTOMCat occulomtor trochlear opthalmic branch of trigeminal maxillary branch of the trigeminal internal carotid artery abducent
how does CSF get from the lateral ventricles to the 3rd ventricle?
through the interventricular foramina (foramina of monro)
how does CSF get from the 3rd to 4th ventricle??
through the cerebral aqueduct (aqueduct of Sylvius)
What is the top nerve in the cavernous sinus?
Occulomotor
What is the blood vessel passing through the cavernous sinus? What nerve is closely related to it?
Internal carotid artery
Abducens
What are the bottom 2 nerves passing laterally and inferiorly in the cavernous sinus?
Maxillary and opthalmic branch of the trigeminal (superior to inferior)
What would you see clinically in a patient with a venous thrombosis in the cavernous sinus?
Headache - cos raised ICP
opthalmopgeia (CN 3,4 and 6)
orbit swelling - increase in pressure with no drainage
ptosis (drooping of the eyelid) (CN V2)
facial numbness (CN V1+2)
maybe seizure
maybe LOC
Where is Broca’s area located?
inferior frontal gyrus - usually left (dominant)
What is the blood supply to Broca’s area? What symptoms do you get when there is a stroke in this area?
Left middle cerebral artery - expressive aphasia - an inability to form language (spoken or written)
displays effortful speech
Where is wernicke’s area?
superior temporal gyrus - usually left (dominant)
What sulcus is the primary occipital cortex found around?
Calcrine sulcus
What makes up the limbic system?
hippocampus, fornix, mamillary bodies, thalamus, hypothalamus, cingulate gyrus
What role does the limbic system have?
Emotions, memory, behaviour and olfaction.
HC - long term memory formation
amygdala - significant stimuli eg fight or flight
where is the nucleus accumbens? what is it’s role?
rostral to the preoptic hyptothalamus
reward centre of the brain - dopamine and serotonin intereactions
if you have a left middle cerebral artery infarct what clinical features would you see?
expressive dysphasia, right sided spastic hemiparesis, right sided sensory deficit, right hemispatial neglect
What vessel do the vertebral arteries arise from?
Subclavian artery
What makes up the posterior circulation?
Posterior cerebral artery + Vertebral arteries
what does an extra dural haemorrhage look like on a CT scan?
Lemon shaped
What does a subdural haematoma look like on a CT scan ?
Banana shaped
What is the function of the insular?
emotion, homeostasis, perception, motor control, self-awareness, cognitive functioning and interpersonal experience.
