Question

select all that apply
which of the following can freely pass through the blood - brain barrier? more than one answer may be correct.
glucose
oxygen
alcohol
large proteins

Explanation:

• Glucose: It is transported across the blood - brain barrier via specific glucose transporters (GLUT - 1).
• Oxygen: Small, non - polar molecules like oxygen can freely diffuse through the lipid bilayer of the endothelial cells forming the blood - brain barrier.
• Alcohol: It is a small, lipid - soluble molecule and can pass through the blood - brain barrier by simple diffusion.
• Large proteins: They are too large and polar to pass through the blood - brain barrier without specific transport mechanisms (which they lack in this context).

Answer:

glucose, oxygen, alcohol