intro to neuro lecture Flashcards
What are the two pairs of vessels that supply the brain?
internal carotids and vertebral arteries
Describe path of ICA…
Ascends the neck, traverses petrous temporal bone, goes thru cavernous sinus, ophthalmic artery branches off as IC enters subarachnoid space.
ICA travels along optic chasm and bifurcates into middle cerebral MCA and Anterior cerebral arteries. (ACA)
Prior to this branch anterior choroidal and posterior communicating artery come off ICA
This artery is long and thin, as well as clinically significant as it is involved in strokes.
Also supplies many different structures; optic tract, choroid plexus in temporal horn of lateral ventricle, deep structures (internal capsule, thalamus, hippocampus) sometimes cerebral peduncle.
What is the Ant. Choroidal artery!
Posterior communicating Artery does what?
PCA is part of the verterbral system so it interconnects ICA & vertebral vascular supply
Anterior Cerebral Artery supplies…
The medial parts of the frontal and parietal lobes. *Some branches extend over the dorsolateral surface. * Note the 2 ACA’s are connected by the anterior communicating artery.
Middle Cerebral Artery supplies…
Supplies most of lateral cerebral hemispheres.
* Runs laterally into lateral sulcus, divides into many branches.
Defintion and function of perforating arteries…
Arise basically from all arteries at the the base of the brain.
*Supply basal ganglia, thalamus and the internal capsule.
can be involved in strokes and cause neurologic deficits out of portion to size.
Vertebral-basilar system supplies…
Supplies the brainstem and cerebellum.
* Vertebral arteries run along lateral medulla, fuse to bailer artery at pons
Prior to joining basilar artery, the vertebral artery gives rise to 3 things….
- Posterior spinal artery = supplies post. 1/3 of spinal cord.
- Anterior spinal artery = supplies Ant. 2/3 of spinal cord.
- PICA: supplies inferior cerebellum and lateral medulla.
Basilar artery bifurcates at midbrain into 2 PCA’s, however prior tot this bifurcation it gives off 2 other arteries….
- AICA = supplies ant. portions of the inferior surface of cerebellum (flocculus) and caudal pons.
- SCA = supplies superior cerebellum, caudal midbrain and rostral pons.
Posterior cerebral artery (PCA) supplies…
Branches of PCA supply medial & inferior surfaces of temporal and occipital lobes.
Branches also go to rostral midbrain and posterior diencephalon.
Circle of Willis definition and function…
- it interconnects ICA and vertebral-basilar system via Post. communicating artery.
- Ant. communication interconnects right and left side of circle.
*Typically little blood flow here until you stroke out…..
Three main mechanisms for cerebral regional change in blood flow:
- Autoregulation = vessels are stretched, so constrict when decrease in pressure and dilate when pressure increases.
- Collaboration of brain & vessels = response to increased brain activity (glutamate sensing)
- Cerebral vascular autonomics = (may be more important at extremes of autoregulatory range
What is the blood-brain barrier? What is it made of? And how does material get across?
Refers to anatomic and physiologic barrier that controls movement of materials from extracellular fluid of body to extracellular fluid of brain.
Barrier includes arachnoid, endothelial tight junctions and lack of pinocytic vesicles.
- Lipids-soluable substances go thru
- glucose crosses by facilitated diffusion
- other substances are actively transported across.
Circumventricular organs are…
areas where cerebral capillaries are fenestrated allowing open communication between blood and brain extracellular fluid.
- Located around 3rd and 4th ventricles
- Some have sensory function )monitor CSF composition)
- Some release Hormones from neuronal endings into the blood.
- Specialized ependymal cells, tancytes overlie ventricular surface.
Describe Brain drainage (veinous system)
Drainage occurs thru a system of cerebral veins that empty into dural sinuses to the IJV and basilar venous plexus at the base of the brain.
*Cerebral venous system has numerous anastomosis, unlike the rest of the body (to protect from stroke)
Where does superficial venous system drain to?
Most empty into superior sagittal sinus
Where does deep venous system drain to?
Drains internal structures & empties into straight sinus
Three commonly found superior veins are…..
- Superficial middle cerebral vein
- Superior anastomotic vein
- Inferior anastomotic vein
What is the major Deep Vein?
- Internal cerebral vein formed by confluence of septal vein and thalamostriate vein, joined by choroidal vein.
- This paired vein flows to great cerebral vein of galen, then to straight sinus.
The ________ Vein forms near the optic chasm and drains orbitofrontal cortex, insula, inferior basal ganglia and parts of the temporal lobes.
Basal Vein
*Also joins great vein of galen and flows into straight sinus.
Tearing of bridging veins is a ________.
Subdural hematoma
Tear of meningeal arteries between skull and dura is a _______.
Epidural hematoma.
Space between dura and calvaria…
Epidural space
Space in innermost dural layer near dura-arachnoid space…
Subdural space
_______ are major sights of CSF reabsorption into the venous system.
Arachnoid Vili
*CSF> venous pressure
______ is found beneath the uncut in the temporal lobe.
Amygdala
The Hippocampus is found where?
In the medial temporal lobe.
What is the function of the basal ganglia?
Involved in Movement control.
The caudate and putamen (of the basal ganglia) make up the _______.
Striatium
The Putamen and globus pallidus (of the basal ganglia) make up the _____.
Lenticular nucleus
What is the function of the limbic lobe?
Limbic lobe is important in emotional responses, drive-related behaviors & Memory.
________ consists of mostly cingulate and parahippocampal gyri.
Limbic lobe.
Where is the primary visual cortex located?
in the banks of the calcarine sulcus (Occipital lobe) and surrounding cortex.
- Occipital lobe is almost exclusively visual in function.
- Vision also associated with temporal lobe too.
Where is the primary auditory cortex located?
in the superior temporal gyrus of the temporal lobe.
Where does language comprehension take place?
- Wernike’s area of temporal lobe. (posterior aspect of one hemisphere, usually left)
- Inferior parietal lobule (of parietal lobe) usually left side.
Where does higher order visual processing take place?
in much of the temporal lobe.
What is the function of the Postcentral gyrus (of the parietal lobe)?
Postcentral gyrus is the primary somatosensory cortex, concerned with initial processing of tactile and proprioceptive info.
___________ is responsible for complex aspects of spatial orientation and directing attention.
much of Parietal lobe.
What are the 4 functional areas of the frontal lobe?
- Precentral gyrus
- Premotor & supplemental motor areas (part of percentile, nearby portions of superior middle frontal gyri)
- Broca’s area (left inferior frontal gyrus)
- Prefrontal cortex. (rest of frontal lobe)
_______ is responsible for executive functions (personality, foresight, insight)
Prefrontal cortex
Broca’s area is responsible for what?
Production of spoken and written language.
What is the function of the precentral gyrus?
- Primary motor cortex
- Origin of descending pathway
- Initiates voluntary movements.
What are the two main dural reflections?
Falx cerebri & Tentorium cerebelli
What is the origin of the descending motor pathway?
The Precentral Gyrus!
Parietal lobe divisons (lateral)….
- Postcentral gyrus
- Superior parietal lobule
- Inferior Parietal lobule
Parietal lobe divisons (medial)..
- Precuneus (lower)
- Paracentral lobule (upper)
Where are the Occiptotemporal & lingual gyri located?
Medial aspect of temporal lobe (Lingual is smaller and more superior *Lingual is also in occipital lobe!)
What does the epithalamus contain?
pineal gland and surrounding structures
What is Massa intermedia or Intrathalamic adhesion?
Area of thalamic fusion across midline (not seen in all brains)
What marks the borders of the third ventricle?
Stria medullaris
What separates the thalamus and hypothalamus?
The hypothalamic sulcus in the wall of the third ventricle. (Hypothalamus lower half)
________ emerges from the interpeduncular fossa.
Oculomotor nerve (CN III)
Where does Trochlear (IV) emerges from ______
the Dorsal aspect of the brainstem (its the only one to do so!)
CN XI emerges from where?
Upper cervical spinal cord
__________ is responsible for eye movements and vestibular function.
The Flocculonodular lobe of the cerebellum
Anterior lobe of cerebellum is responsible for what?
spinal cord input and Trunk & limb movement
Posterior lobe of cerebellum is responsible for what?
input from cortex, coordinates voluntary movements.
The basal ganglia is involved in what?
movement control
Describe path of CSF Circulation…
From lateral and 3rd ventricles –> down aqueduct ——> 4th ventricle —> median & lateral apertures ——>down the brainstem & cord —> to arachnid granulations and into superior sagittal sinus.
______ is the space in the tantrum were brainstem passes thru.
tentorial notch or tentorial incisure
