By continuing your visit to this site, you accept the use of cookies. They ensure the proper functioning of our services and display relevant ads. Learn more about cookies and act

Not yet registered? Create a OverBlog!

Create my blog

What is the blood-brain barrier

The 'Blood Brain Barrier' is a barricade of cells which acts as a sieve to prevent many substances from the blood such as drugs or chemical compounds, viruses which cause diseases, radioactive ions etc. into entering the central nervous system.

Blood Brain Barrier (BBB)

The BBB is composed of three cellular components of the brain microvasculature namely endothelial cells, astrocyte end-feet and pericytes (PCs). It is formed by a combination of special glial cells (astrocytes) with blood vessels and is critical for maintaining the homeostasis in the brain. Essential nutrients such as carbon dioxide and oxygen and substances such as steroids can pass through the BBB easily, and some such as caffeine and ethanol pass via the lipid membranes of the cells. Substances such as chloride ions, sodium and potassium need specific carrier molecules along with to reach the brain, and some substances cannot pass through at all (which can damage the brain). BBB is located in the endothelial cells of the capillaries of the brain and usually develops on the 28th day of being born. History of BBB The concept of BBB was first suggested by bacteriologist Paul Ehrlich. While conducting an experiment, he found that intravenous dyes if injected into the body stained all the tissues of the body except the brain. Later, in 1913, Edwin Goldmann directly injected the dye in the brain which stained the brain and not the rest of the body indicating a compartment between the two. This concept was further proposed by Lina Stern in 1921. Finally in 1960, some scientists used electron microscopy and electron - dense tracers to detect and confirm the existence of BBB.

BBB’s structure

The brain’s endothelial cells are attached by tight junctions of high electrical resistance which act as a barrier against molecules, whereas the endothelial cells of peripheral tissues in the body ensure a free transcellular movement of molecules. Moreover, the capillaries of the brain are in contact with foot processes of astrocytes which segregate neurones from them. Some areas such as postrema and the posterior pituitary do not have the BBB as the pituitary has to allow some neurosecretory products to reach the blood on the brain. BBB is absent in the subfornical organ so that water balance and other homeostasis functions can be maintained. Dysfunction of BBB
Impairment of tight junctions can cause stroke or neuroinflammatory disorders. Other diseases affecting the blood brain barrier are meningitis, epilepsy, multiple sclerosis, neuromyelitis optica, late-stage neurological trypanosomiasis (sleeping sickness), progressive multifocal leukoencephalopathy (PML), de vivo disease, alzheimer's disease and HIV encephalitis. All of these diseases cause harm as they allow unwanted substances to pass to the blood on the brain, thereby affecting BBB.

Same category articles Illness & diseases

Where to get online medical advice

Where to get online medical advice

Web health advice is available in abundance and it is important to differentiate between sources that are reliable and sources that are biased. Speaking to medical professionals online is now possible, as is gaining impartial articles that can help you to recognise symptoms. Read this article to know where to get online medical advice.
What is paranoid schizophrenia?

What is paranoid schizophrenia?

Schizophrenia is a severe mental illness which affects around 1% of the population and is equally common in both men and women. One of the most prevalent types of schizophrenia is paranoid schizophrenia, where sufferers are typically highly suspicious of other people around them and may have delusions of being persecuted.
All about the Anthony Nolan Trust

All about the Anthony Nolan Trust

Anthony Nolan is a company in the UK that works to save people who need urgent stem cell transplants by locating matching donors. The company claims that it is the country's most successful stem cell register, and involves itself in research in an effort to improve the success of transplants by encouraging donating. This is a guide to the essential facts about the company and what it offers.
How to treat swollen eyes

How to treat swollen eyes

Under eye swelling can make you look and feel old and tired. If you have puffiness under the eyes, dark circles and irritation, you can soothe your eyes at home with simple remedies. For serious eye irritation, painful eyes or any trouble with your vision, make sure to see your doctor. In this article, find out how to treat swollen eyes.