A biological barrier is a natural
selectively permeable membrane
Semipermeable membrane is a type of Chemical synthesis, synthetic or Biological membrane, biologic, polymeric membrane that allows certain molecules or ions to pass through it by osmosis. The rate of passage depends on the pressure, concentration ...
that protects certain organs or tissues by allowing some substances to pass through them, and blocking entry of other substances.
It can refer to:
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Blood-brain barrier, a biological barrier that prevents entry of harmful substances into the brain by selectively allowing some substances to pass through it
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Blood-testis barrier, the biological barrier between blood and testes
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Blood-placental barrier, the biological barrier between a pregnant individual's blood and foetal blood (blood of one or more foetuses)
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Blood-CSF barrier, the biological barrier between blood and cerebrospinal fluid (CSF; also called brain fluid)
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Blood–spinal cord barrier, the biological barrier between blood and the spinal cord
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Blood–saliva barrier, the biological barrier between blood and saliva
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