Exam 2 Flashcards
(45 cards)
Arteries if the forebrian
Anterior cerebral artery—
Middle cerebral artery—- branches of the internal carotid artery
Posterior cerebral artery– (Gets blood from vertebral artery too)
Anterior Cerebral Artery
Supplies most of the medial brain
Arches over the corpus callosum
Middle Cerebral Artery
Biggest of the 3
Receives 80% of the internal carotid blood flow
Located along the lateral fissure
2 branches: upper (frontal & parietal) and lower ( temporal & occipital)
Supplies blood to 2/3 of the lateral surface
Lateral striated arteries –> lesion pyramidal tract fibers @ internal capsule.
Posterior Cerebral Artery
25% of the blood flow comes from the internal carotid artery. Other 75% comes from vertebral artery Supplies occipital (medial part) and temporal (inferior part) lobes.
Blood supply to the brain
Vertebral Artery
Posterior inferior cerebellar artery- lateral side of the medulla
Anterior spinal artery- ventral and medial aspects of the medulla
Posterior spinal artery- dorsal and medial aspects of the medulla
Blood supply to the brain
Anterior Inferior Cerebellar Artery
Supplies the lateral sides of the pons and the inner ear ( artery it the inner ear, labyrinthine artery)
Blood supply to the brain
Pontine
Small and striated
Supplies midpons
Blood supply to the brain
Posterior Cerebral
Supplies the midbrain
Venous Drainage
Superficial
Superior brain-superior sagittal sinus
Middle brain-cavernous sinus
Inferior brain-transverse sinus
Venus Drainage
Deep
Great cerebral vein of Galen
Regulation of blood flow
Auto-regulation:
- H+ concentration
- intraluminar pressure
Meninges
Dura mater
Arachnoid membrane
Pia mater
Difference in brain and vertebral canal
Cranial dura
Two layers: Periosteal layer-rich blood supply Meningeal layer-no vascular supply Potential space - located inbetween the two layers Innervated by Trigeminal nerve c1-c3
Folds of the Meningeal layer
Falx Cerebri (longitudinal fissure) Tentorium Cerebelli Falx Cerebelli (separating the cerebellum)
Cranial arachnoid
Space between dura and arachnoid = subdural space Arachnoid trabeculae suspends the brain in the CSF Arachnoid cisterns (found near sinuses, pouches)
Arachnoid granulation
CSF passes through the sinuses (helps get ride of old CSF)
Cranial pia
Follows contours of the brain (right up against the brain! big space between arachnoid and pia)
Spinal dura
One layer
Epidural fat and a plexus of veins separates intro the vertebral periosteum.
Ends at S2
Coccygeal ligament ( filum terminale externa) anchors it to periosteum of cx1 and cx2
Spinal arachnoid
Potential subdural space
Trabeculae suspends the spinal cord
Lumbar cistern L2-S2 ( pouch, elongated roots, cauda equina found within
Spinal pia
Filum terminale
21 (pairs) denticulate ligaments attach to dura from foramen magnum to below tv12
Pia is tightly attached to spinal cord as it is in the brain
Extention-filum terminale interna, has pia and dura inside the dural sac, thicker.
Dural sinuses
Lined with endothelium No valves Collects blood from brain and emissary veins Collects CSF from subarachnoid space Drains into the internal jugular vein Carry deoxygenated blood
Anterior inferior sinuses
Cavernous - sellar tursica,surround pituitary gland
Sphenoparietal - less wing of sphenoid bone
Superior petrosal
Inferior petrosal
Basilar plexus - lies along basic skull, clivous
Posterior superior sinuses
Superior sagittal
Inferior sagittal Both longitudinal fissure
Straight - runs bw tentorium falx Cerebelli
Transverse - runs in sigmoid sinus
Sigmoid
Confluence - all sinuses come together here, creating a whirlpool. Sucks the blood up by creating a vacuum.
Cerebral spinal fluid
Formed by the choroid plexus
- 14-35ml per hour
- 800 ml per day
- 150 ml at any given moment
High sodium, potassium, and chloride
Low in protein, lymphocytes, and epitheliod cells
Cushions the brain and removes waste products
