Week 1 Lecture 6 Flashcards
What is the brain-blood barrier (BBB)?
Why is the BBB important?
The ionic composition of the extracellular fluid around the neuron must be carefully controlled because: the membrane is dependent on concentration gradients and neurotransmitters cannot be floating around for no reason
What could the BBB be thought of as?
A two-fold entity in which there are two barriers, one between the blood vessel and interstitial fluid (fluid surrounding neurons) and one between the blood vessels and cerebrospinal fluid (CSF). There is free diffusion between interstitial fluid and CSF which have the same composition
What is Parkinson’s disease?
A neurological disease associated with low levels of dopamine, a neurotransmitter that cannot cross the BBB; however, L-DOPA, a dopamine precursor, is used as a treatment
What is MSG?
A compound found in foods that is associated with thirstiness and neck/muscle stiffness
Is the entire brain protected by the BBB?
No, although most of the brain is protected by the BBB, it is not continuous. The BBB is broken in areas that interact with the endocrine system e.g. hypothalamus and pituitary gland or require sensitivity to plasma e.g. circumventricular organs
What are the encasing of the brain?
Skull, meninges, and reticular formation
What are the three layers of connective tissue in the meninges
- Dura mater: tough sac containing the brain and spinal cord
- Arachnoid membrane: delicate tissue
- Pia mater: lie right on top of the brain and tethered to the arachnoid membrane
What is between the arachnoid membrane and pia mater?
Subarachnoid space
What is the subarachnoid space?
Filled with CSF and protects brain from mechanical stress, BBB present
How are endothelial cells of blood vessels (BV) and cells in the brain different?
The endothelial lining of BVs contain large gaps (fenestrations (windows)) that allow molecules to pass through while the endothelial cells in the brain are tightly bound via tight junctions which creates the BBB
What are ventricles
Hollow cavities deep inside the brain, filled with CSF, 4 in total
What are the 4 ventricles and how are they connected to each and the spinal cord?
- Lateral ventricle (LV): large curved ventricles found in both cerebral hemispheres (paired)
- LV empties into the 3rd Ventricle which is midline and communicates with the 4th ventricle via the Aqueduct of Sylvius
- Connected to the 4th ventricles is Central Canal which is connected to the middle of the spinal cord
