The Blood-Brain Barrier The Blood-Brain Barrier

Perhaps the first scientific researcher to document the occurrence of a blood-brain barrier was Paul Ehrlich (1885, 1906) (10:1). He observed that intravenous injection of water-soluble vital dyes colored all of the body's tissues except for those of the central nervous system (CNS). The physiologic mechanisms underlying this "hindrance to diffusion," however, remained unclear for many years (5:1-40). It wasn't until the early years of this century, that Stern and Gautier (1921, 1922) studied the movement of different substances into the brain. From their observations, the two researchers concluded that the cerebrospinal fluid (CSF) acts as an intermediary between the blood and the CNS (6:28). Eventually, their work led to the identification of two separate barriers: the blood-CSF barrier and the BBB.

. . .
tems permit for the directional movement of solutes (9:87-88). By allowing the CNS endothelium to act as both a passive and an active barrier, the tight junctions ultimately serve to regulate the composition of the interstitial fluid bathing the brain's neurons and glia. Since these cells are highly responsive to the extracellular fluid's ionic composition, the endothelial cell tight junctions play a significant role in CNS function. In fact, tight junctions are only found in the capillaries and postcapillary venules of the cerebral cortex (3:107). Other important cellular components of the BBB include astrocytes, pericytes, and microglial cells. Astrocytes and pericytes generally occur at the abluminal surface of the endothelium associated with its basal lamina. For example, astrocyte cell bodies may extend endfoot processes to the endothelial cells' basement membrane. In contrast, pericytes are contractile cells have been found to extend long processes around the capillary endothelium. Thirdly, the microglia occur primarily in the perivascular region. These cells are thought to be involved in the immunopathology of several CNS diseases (9:87-88). Clearly, the blood-brain barrier does more than function merely as a
. . .

Some common words found in the essay are:
Fortunately BBB, BBB German, Stern Gautier, Book Company, Blood-Brain Barrier, Raven Press, blood-brain barrier, Paul Ehrlich, Essentially BBB, Davson History, Nilaver Hammerstad, york ny, tight junctions, york ny raven, barrier cellular molecular, molecular biology, biology york, barrier cellular, cellular molecular, ny raven, endothelial cells, cellular molecular biology, molecular biology york, press 1993, blood-brain barrier cellular,
Approximate Word count = 2052
Approximate Pages = 8 (250 words per page)

More Essays on The Blood-Brain Barrier The Blood-Brain Barrier