Which statements are true regarding the blood-brain barrier (BBB)? (Select all that apply.)
A)The BBB is dependent on astrocytes.
B)It uses the meningeal layers of the brain.
C)It restricts the flow of large molecules, such as plasma proteins.
D)Naturally occurring inflammatory mediators affect the BBB.
E)Becomes increasingly permeable with aging

Question

Quizplus · Accepted Answer

The BBB is a term used to describe cellular structures that selectively inhibit certain substances in the blood from entering the interstitial spaces of the brain or CSF. This term emphasizes the impermeability of the nervous system to large and potentially harmful molecules. Astrocytes wrap their foot processes around the epithelial cells of brain capillaries, thereby contributing to the formation of the BBB. Tight junctions between capillary endothelial cells form a barrier that regulates the passage of ions (e.g., sodium, potassium) that could interfere with nerve transmission, prevent toxins from entering the brain, and promote transport of nutrients and the removal of metabolites. Hormones, neurotransmitters, and inflammatory mediators can affect BBB permeability. The BBB becomes increasingly permeable with age. The statement regarding the meningeal layers of the brain is incorrect.

Which Statements Are True Regarding the Blood-Brain Barrier (BBB)? (Select