Page 45 - Physiology and Pathophysiology MNU 2024-2025 نظرى

Clinical pharmacy 2024/2025 Level 2 Pharm D Physiology and Pathophysiology (MD303)

Blood Brain Barrier (BBB)

❖ barrier between cerebral capillary blood and the CSF.
Anatomy ❖ It consists of the endothelial cells of the cerebral capillaries and the choroid
 CSF fills the ventricles and the subarachnoid space.

plexus epithelium.

1. Maintains a constant environment for neurons in the CNS.

2. protects the brain from endogenous or exogenous toxins.

3. prevents the escape of neurotransmitters from their functional sites in the CNS

into the general circulation.
Function 4. Drugs penetrate the blood–brain barrier to varying degrees.

 For example, nonionized (lipid-soluble) drugs cross more readily than ionized

(water-soluble) drugs.

 Inflammation, irradiation, and tumors may destroy the blood–brain barrier and

permit entry into the brain of substances that are usually excluded (e.g.,

antibiotics, radiolabeled markers).

Ventricles of the brain

Within the brain there are four irregular shaped cavities or ventricles, containing

cerebrospinal fluid (CSF).

* They are

1) Right and left lateral ventricles. 2) Third ventricle. 3) Fourth ventricle.

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