Blood Brain Barrier Flashcards
(22 cards)
Who taught the lecture on BBB?
Dr. Elwood K. Walls
What are special properties of BBB?
- less endocytosis
- less vesicular transport
- tight junctions
- specific transport systems
- astroglia endfeet
What percent of the body’s energy goes to the brain?
20%
What prevents toxic or unwanted substances circulating in the blood of the brain?
tight control of brain extracellular fluid or BBB
What are unique properties of the BBB?
CNS vessels are continuous nonfenestrated vessels
Who found the BBB?
Paul Ehrlich and Edwin Goldmann found the BBB when they noticed that vital dyes got in the brain only when injected directly into CSF
What role do endothelial cells play?
they connect by tight junctions to control what substances enter; they lack fenestrations and pinocytotic vesicles
What can pass endothelial cell membrane?
lipid-soluble gases (O2) and lipophilic substances (alcohol and psychoactive drugs)
How do metabolites get across epithelial cells?
specific transport mechanisms (ie. transporters, ion channels, exchangers)
What does BBB maintain?
It maintains homeostasis of CNS extracellular fluid and sustains optimal microenvironment for neurons and glia
What relationship do astrocytes have with the blood vessels?
They have endfeet that wrap portions of the blood vessel. They transport materials from blood vessels to the neurons
How do we get lifesaving drugs into the brain?
- Hyperosmotic solutions
- Microcatherization
- Microbubbles
- Attaching to carriers
What areas of the brain do not have a BBB? Why?
circumventricular organs, CVOs (hypothalamus and pituitary glands) because they need to secrete substances that enter blood stream or to respond to blood-borne substances
What are disorders of BBB?
- brain tumors and brain metastases (leaky vessels)
- Bacterial Meningitis (breakdown of barrier)
What produces CFO?
choroid plexus of lateral, 3rd and 4th ventricles
Where does CSF flow to from choroid plexus?
3rd ventricle, 4th ventricle, central canal as well as subarachnoid space between Pia mater and arachnoid maembrane
Where is CSF reabsorbed?
In the arachnoid granulations to be cleared into venous blood
How often is CSF replaced?
every 6 horus
What is composition of CSF similar to? What contains more carbon dioxide?
plasma or brain ECF; CSF has more carbon dioxide
Functions of CSF?
- provides a pressurized fluid-mechanical cushion to the brain
- removing harmful metabolites
3.Distribution of polypeptide hormones
Diagnostics and medical applications
- Cloud appearance and elevated presence of leukocytes indicates infection
- In multiple sclerosis immunoglobulin concentration is elevated
What is a hydrocephalus shunt?
It is a shunt designed to relieves pressure in hydrocephalus; infants have brain distorting due to blocked flow of CSF in the cerebral aqueduct
