Your brain needs 15 percent of your total blood volume. It is through this precious blood that it gets the oxygen and glucose that is so vital for it to function. It is protected by a membrane, cushioned by fluid and protected, again, by bone. And, yet, there are various types of diseases that can affect it.
Meningitis
The meninges is the name of the membrane that completely covers your brain. It has three layers, as well as a fluid, called the cerebrospinal fluid, that circulates between two of the layers. Both the meninges and the fluid serve to protect your brain, but, if a microorganism is able to reach the meninges, infecting where the fluid circulates, then you have meningitis. Meningitis is the inflammation of the meninges, as stated by Ramzi Cotran, M.D., et al in the book "Robbins Pathologic Basis of Disease."
Encephalitis
Encephalitis is inflammation of the brain itself. While meningitis can be caused by bacteria, viruses or fungi, according to Elizabeth Corwin, Ph.D., in "Handbook of Pathophysiology," encephalitis is usually caused by viruses. Many times, the viral infection is carried by a mosquito. Other times, encephalitis is due to an infection directly caused by the cytomegalovirus or by the herpes simplex 1 virus.
Cerebral Abscess
Cerebral abscesses develop as a result of a head wound, an infection that spread to your brain via your bloodstream or from a nearby infection in your sinuses or skull. At first, pus develops in the infected area. Then, a capsule made of a thin membrane develops and forms a wall around the infection, says Cotran.
Tumors
Cotran writes that 50 percent of all brain tumors are primary brain tumors, meaning that they develop within the brain. The other 50 percent are metastatic; that is, they spread to the brain from a tumor located elsewhere. The tentorium cerebelli is the name of a thick membrane that separates your cerebellum from the back of your brain. Tumors that are located above the tentorium cerebelli, called supratentorial tumors, are usually found in adults. The most common supratentorial tumors are called glioblastomas, meningiomas and schwannomas. Tumors found below the tentorium cerebelli are called infratentorial tumors, and these are usually found in children. The most common infratentorial tumors are called astrocytomas, medulloblastomas and ependymomas.
Neurodegenerative Diseases
This term refers to diseases that cause a slow, progressive loss of nerve cells (neurons) in the brain. Such diseases include Alzheimer's, which is the most common cause of dementia, with its loss of neurons that release a substance called acetylcholine. Parkinson's is a neurodegenerative disease where there is a loss of neurons that release dopamine. In Huntington's, which is hereditary, the diseased state results from the loss of GABA. Acetylcholine, dopamine and GABA are all vital, as they are used by neurons to send signals, says Corwin.
Alcoholism
Chronic (long-term) alcoholism causes a diseased brain. First of all, it causes the brain to atrophy; that is, to get smaller. Second, it can also cause what is referred to as Wernicke-Korsakoff syndrome, with problems of eye movement, unsteadiness in walking, mental confusion and memory loss. Merck explains that all this is due to a thiamine deficiency from a poor diet.
References
- "Handbook of Pathophysiology"; Elizabeth Corwin, MSN, Ph.D., FNP; 2000
- "Robbins Pathologic Basis of Disease"; Ramzi Cotran, M.D., Vinay Kumar, M.D., Stanley Robbins, M.D.; 1994
- Merck: Alcohol
