W2: Blook Supply, Telencephalon, Diencephalon Flashcards
What protects the CNS?
Blood brain barrier
Blood brain barrier
Location: surrounding the CNS
Made of: endothelial cells that are NOT fenestrated but have tight junctions.
Function: To protect the CNS (no bacteria, toxins, proteins, blood cells are transported)
Fenestrated
to have pores
What two major arteries supply the brain with blood?
1) Internal carotid artery
2) Vertebral/basilar arteries
Internal carotid artery
supplies blood to eyes, anterior/middle cerebral artery and mid sagittal.
Middle cerebral artery
(most important)
supplies majority of lateral surface of brain and 2/3 of temporal lobe (on the lateral side)
Vertebral/basilar artiries
Branches off aorta, assends to lateral part of vertebrae to skull to foramen magnum and ends in the posterior cerebral artery.
Posterior cerebral artery
Comes from verebral artery
Supplies occipital lobe and inferior side of temporal lobe.
What arteries make up the Circle of Willis?
1) Anterior communicating artery
2) Anterior cerebral artery
3) Internal chorotid artery
4) Middle cerebral artery
5) Posterior cerebral artery
6) Basilar artery
7) Posterier communicating artery
Anterior cerebral artery
connects the hemisphere
Stroke
Caused by circulatory problems in the CNS and can lead to a loss of cortical function.
Hemiplegia
Blockage of entire middle cerebral artery
TPA
Tissue plasminigen activator
Dissolves clot if administered within 3-6hrs.
Cannot administer if bleeding
Symptoms of there is a black in the posterior cerebral artery
Visual deficit
Learning/memory
Where do the superior and inferior sagittal sinuses and straight sinus drain to?
They drain posteriorly into the transverse sinuses and then the sigmoid sinuses.
How does venous blood and CSF exit the skull? How does it return to circulation?
Exit: internal jugular
Re-enter: superior vena cava
Basal Ganglia
Location: Telencephalon
Made of: caudate, putamen, globus pallidus
Function: integrates motor & sensory information & initiates voluntary movement
Corpus Striatum
Caudate
Putamen
Afferent axons of the caudate-putamen make up what regions?
1) Corticostriate
2) Thalamostriate
3) Nigrostriate
Where do the Corticostriate, Thalamostriate, Nigrostriate project from?
1) Corticostriate - from all parts of the cerebral cortex
2) Thalamostriate - from the thalamus
3) Nigrostriate - from the substantia nigra
How are afferent axons organized?
somatotopically
Parkinson’s Disease
A degenerative disease of the basal ganglia that produces movement disorders. Involves loss of cell bodies in substanita nigra that project azons to the casudate-putamen and use dopamine for neurotransmission. Treatment for Parkinson’s patients is to give them L-DOPA, which crosses the blood brain barrier and is converted to dopamine by DOPA decarboxylase.
Symptoms: slow motor function, trouble initiating motor function, resting tremor
Basal ganglia motor command curcuit
Motor/somatosensory neurons of cerebral cortex > putamen > globus pallidus > ventral lateral thalamus > back to motor areas of cortex and facilitate cortical output.
Huntington’s Disease
A rare autosomal dominant genetic disease causing degeneration of GABAergic neurons in the causdate-putamen and produces severe motor disorders. Currently there are no treatments but have located the gene, so effective genetic screening and couseling is available.
Symptoms: hyperactive/involuntary movement, severe change in cognition and personality.