Download Free Medical How does blood flow inform us about brain function PowerPoint Presentation

How does blood flow inform us about brain function PowerPoint Presentation

DOWNLOAD MEDICAL POWERPOINT PRESENTATION

About This Presentation

Description : Check out this medical presentation on Artery, which is titled "How does blood flow inform us about brain function?", to know about cerebrovascular anatomy and neural regulation of CNS blood flow.

Tags : Artery, blood flow, brain function, cerebrovascular anatomy, neural regulation, CNS blood flow

Published on : Jun 02, 2021 | Views : 1574 | Downloads : 2

Shareable Url :

Embed Code :

Comment

Transcript

Slide 1-

How does blood flow inform us about brain function? Cerebrovascular anatomy & neural regulation of CNS blood flow Neurovascular coupling HST 583 Brad Dickerson, M.D. bradd@nmr.mgh.harvard.edu
Slide 2-

How does blood flow inform us about brain function? Cerebrovascular anatomy & neural regulation of CNS blood flow Cerebral blood flow: intro Cerebrovascular anatomy Neurotransmitter systems & neural regulation
Slide 3-

Blood flow and the organ of thought “…blood supply to any part of the cerebral tissue is varied in accordance with the activity of the chemiccal changes which underlie the functional action of that part…” -- Roy & Sherrington, 1890 “We must suppose a very delicate adjustment whereby the circulation follows the needs of the cerebral activity. Blood very likely may rush to each region of the cortex according as it is most active, but of this we know nothing.” -- W. James, 1890
Slide 4-

Blood flow and the organ of thought Slide courtesy of M. Raichle
Slide 5-

Blood flow and the organ of thought The brain requires blood for: General support of maintenance functions, like every organ - requires energy (ATP) Specific localized support of functional activity related to neural activity - requires energy (ATP) Blood supplies substrates for energy production: Glucose and oxygen ~750 ml/min
Slide 6-

The route of blood to the head
Slide 7-

The route of blood within the head
Slide 8-

Circle of Willis
Slide 9-

The route of blood within the head
Slide 10-

T1 T2
Slide 11-

The route of blood within the head
Slide 12-

The route of blood within the head
Slide 13-

Scale of the circulatory system Aorta: 2.5 cm (~1 in) Large arteries (e.g., carotid): .5 - 1 cm Arterioles: 10 - 50 um Capillaries: 5 - 10 um (RBC)
Slide 14-

Scale of the circulatory system Large arteries (e.g., carotid): .5 - 1 cm Arterioles: 10 - 50 um
Slide 15-

Scale of the circulatory system Capillaries: 5 - 10 um (RBC)
Slide 16-

Scale of the circulatory system Venules/veins
Slide 17-

The route of blood within the head
Slide 18-

The route of blood within the head
Slide 19-

The route of blood within the head
Slide 20-

The route of blood within the head
Slide 21-

ppt slide no 21 content not found
Slide 22-

ppt slide no 22 content not found
Slide 23-

ppt slide no 23 content not found
Slide 24-

ppt slide no 24 content not found
Slide 25-

ppt slide no 25 content not found
Slide 26-

ppt slide no 26 content not found
Slide 27-

ppt slide no 27 content not found
Slide 28-

Pial arteriolar anastomoses 1 mm From Edvinsson, 1993
Slide 29-

ppt slide no 29 content not found
Slide 30-

AP view: Vertebral artery angiogram
Slide 31-

ppt slide no 31 content not found
Slide 32-

5 mm Cortical capillary vasculature
Slide 33-

5 mm Cortical neural structure
Slide 34-

5 mm Cortical capillary vasculature Grey matter has 2-4 times the capillary density of white matter
Slide 35-

Cerebellar Vasculature
Slide 36-

Inferior Olivary Nucleus and Inferior Cerebellar Peduncle 2 mm From Duvernoy, 1995
Slide 37-

Cerebellar Histology Blue = myelin Pink = neuropil 1 mm From Duvernoy, 1995
Slide 38-

100 mm 500 mm From Duvernoy, 1995
Slide 39-

Cerebellar Cortical Histology
Slide 40-

Molecular Layer Purkinje Cells Granular Layer Cerebellar histology and vascularization From Duvernoy, 1995
Slide 41-

Capillary density in rat brain is proportional to metabolic rate Low levels of CBF Hypothalamus, cerebellum, medulla High levels of CBF Cochlear nucleus, mammillary body, cortex Low levels of CMRglu Hypothalamus, cerebellum, medulla High levels of CMRglu Cochlear nucleus, mammillary body, cortex From Edvinsson, 1993
Slide 42-

Flow of CSF
Slide 43-

CSF return to venous blood
Slide 44-

Large vessels in subarachnoid space
Slide 45-

Blood Brain Barrier What cerebral capillaries have: Tight continuous quintuple-layered intercellular junctions low wall thickness (0.2 um) higher mitochondrial content thick basement membrane What cerebral capillaries don’t have: fenestrations lots of vesicles fluid-filled bulk transport channels
Slide 46-

Blood Brain Barrier Allows passage/transport of small molecules (H2O, O2, CO2), lipophilic molecules (EtOH, heroin), passive transport of glucose, active transport of amino acids/NT precursors Prevents passage of larger molecules (dopamine), charged molecules, etc
Slide 47-

Measurement of blood flow to the brain Aorta 90cm/s, ICA 40cm/s, arterioles 10-250mm/s, capillaries 1mm/s Transcranial doppler ultrasound
Slide 48-

Cerebral autoregulation CBF remains constant over wide range of change in arterial pressure
Slide 49-

Flow is regulated by arteriolar smooth muscle Arterioles: 10 - 50 um
Slide 50-

Sites of CBF Regulation Large diameter vessels (ANS) Smaller diameter arterioles, venules (neurogenic) Must have smooth muscle with appropriate innervation and receptor site to act upon If signaling is at capillary level, message must move upstream to supplying arteriole
Slide 51-

Changes in cerebral blood flow can be prompted by Change in hemical mileu/blood gases Arterial hypercarbia/tissue acidosis/hypoxemia Neurotransmitter systems Autonomic nervous system Sympathetic (NE, Neuropeptide Y) Parasympathetic (ACh, VIP) Dopamine vs noradrenaline Serotonin Localized neural activity
Slide 52-

from hypothalamus and brain stem Global perfusion increase
Slide 53-

NE (fast, short acting) & NPY (slow, longer lasting) From Wilson-Pauwels, 1997 from hypothalamus and brain stem Sympathetic innervation of blood vessels
Slide 54-

Noradrenergic Dopaminergic from hypothalamus and brain stem Sympathetic innervation of cortical pial vessels
Slide 55-

Neurotransmitter systems