Lecture 2: Blood supply and ventricles Flashcards
What artery supplies Wernike’s and Broca’s area?
Middle cerebral artery (as it supplies the lateral surface of frontal and parietal lobes. It also supplies the superior and lateral surface of the temporal lobes and the part of the lateral surface of the occipital lobe.
What artery supplies the primary auditory area?
Middle cerebral artery
What artery supplies the primary somatosensory and primary motor areas?
The anterior cerebral artery supplies the medial and part of the superior surface of the pre-central and post-central gyri - that provide motor outputs and somatosensory innervation to lower limbs. And the middle cerebral artery supplies the lateral surface.
What percentage of blood supply to the brain is provided by the internal carotid arteries and vertebral arteries? What smaller arteries do each of these supply?
2/3 is provided by internal carotid which divides in the the anterior cerebral artery and middle cerebral artery.
1/3 is provided by the vertebral arteries (which splits into:
Posterior inferior cerebellar arteries [PICA}, anterior inferior cerebellar arteries [AICA], superior cerebellar arteries, posterior cerebral arteries and their braches and anterior and posterior spinal arteries.
Which sinus drains into the internal jugular vein?
sigmoid sinus
Which sinus drains into the sigmoid sinus?
transverse sinus
Which sinus drains into the straight sinus?
inferior sagittal sinus
What is the role of the blood brain barrier (BBB)?
To keep out neuroactive and neurotoxic compounds
What type of compounds can easily cross the BBB
Lipophilic compounds (eg. diazepam, caffeine, nicotine, ethanol)
How does D-glucose and essential amino acids cross the BBB?
Via active transport as these compounds are more hydrophilic - and large molecules such as proteins cannot get through.
What are the differences between capillaries of the body and the capillaries of the brain?
Brain capillaries are non-fenestrated with tight junctions between endothelial cells. These endothelial cells are covered by pericytes in basement membrane and reinforced by astrocytic end feet to maintain structure.
What can damage the blood brain barrier?
High blood pressure, infections, specific compounds (quinolinic acid, hormones), brain tumours, multiple sclerosis, brain oedema (stroke or head injury)
How do “desirable” substances get across the blood brain barrier?
D-glucose (but not L-glucose) and essential amino acids cross the BBB by active transport)
Vitamins and hormones cross the BBB by CSF - which is much slower than active transport.
What is de vivo disease?
A disease where glucose transport via GLUT-1 is compromised. This often results in intellectual disabilities as well as other neurological symptoms
How do chemists get drugs across the BBB?
Make drugs more lipophilic, for example, by adding an aromatic component to the molecule - eg. benzene ring .
High intensity focused ultrasound can also disrupt the blood brain barrier temporarily.
