Question 21 ptsWhich of the following statements is CORRECT regarding the blood-brain barrier?Group of answer choicesmicroglial cells help the endothelial cells to form the blood-brain barrierpericytes form tight junctions between endothelial cells in blood vesselsbrain capillaries lack fenestrations and have high pinocytosistight junctions open and close to control the passage of material through the intercellular spacesthe vascular basement membrane contributes to the integrity of the blood-brain barrier

The correct statement regarding the blood-brain barrier is: "the vascular basement membrane contributes to the integrity of the blood-brain barrier."

Here's why:

1. Microglial cells do not help the endothelial cells to form the blood-brain barrier. Microglial cells are a type of glial cell that are the resident macrophages of the brain and spinal cord, and thus act as the first and main form of active immune defense in the central nervous system.

2. Pericytes do not form tight junctions between endothelial cells in blood vessels. Pericytes are contractile cells that wrap around the endothelial cells of capillaries and venules throughout the body. They are located in the capillary wall, where they are embedded in the basement membrane.

3. Brain capillaries do lack fenestrations and have low pinocytosis, not high. This is one of the features that make the blood

The correct statement regarding the blood-brain barrier is: "the vascular basement membrane contributes to the integrity of the blood-brain barrier."

Here's why:

1. Microglial cells are a type of glial cell located throughout the brain and spinal cord. They are the first and main form of active immune defense in the central nervous system. However, they do not help endothelial cells to form the blood-brain barrier.

2. Pericytes are contractile cells that wrap around the endothelial cells of capillaries and venules throughout the body. They do not form tight junctions between endothelial cells in blood vessels.

3. Brain capillaries do lack fenestrations and have high pinocytosis, but this is not the primary factor in the formation of the blood-brain barrier.

4. Tight junctions do not open and close to control the passage of material through the intercellular spaces. They are a type of connection between cells that prevent the leakage of molecules and ions through the space between cells.

5. The vascular basement membrane does contribute to the integrity of the blood-brain barrier. It provides structural support to the cells and tissues of the barrier and helps to maintain its selective permeability.