Cerebral Circulation and the Blood-Brain Barrier

Vocabulary flashcards focusing on the vascular supply of the brain, the role of cerebrospinal fluid, and the mechanisms of the blood-brain barrier.

Four main pipes of cerebral arteries

The anterior circuit, posterior circuit, internal carotid arteries, and the vertebral artery.

Internal carotid arteries

Arteries that go inward to supply the brain.

External carotid artery

The artery that goes towards the skin of the face.

Vertebral artery

An artery that goes up the transverse foramina on the spinal column; the posterior circuit enters via the foramen magnum.

Cerebral blood flow rate

$600-750\,mL/min$, which is approximately the volume of a bottle of wine per minute.

Optic chiasm

Identified as a black X in slide 105; drawing a line through it differentiates the anterior from the posterior circuits.

Middle cerebral artery (MCA)

The most common artery for strokes, supplying half of the brain mass and middle structures including the sylvian fissure.

MCA Superior division

Supplies motor and sensory functions to the face, arm, and hand, as well as Broca's motor speech area.

MCA Inferior division

Responsible for speech and language comprehension.

Anterior cerebral artery (ACA)

Supplies the leg, foot, trunk, hip, genitals, and the motor/sensory cortex of the lower extremities (LE), as well as the cingulate gyrus/limbic system.

Posterior cerebral artery (PCA)

Comes from the vertebral circuit rather than the internal carotid; hooks behind the midbrain to supply the occipital lobe and the thalamus (sensory relay).

Cerebrospinal Fluid (CSF)

Described as 'Gatorade for the NS', it bathes the nervous system, provides shock absorption, and cushions the brain.

Normal CSF pressure

$11\,mm\,Hg$ (11 mm of mercury) of hydrostatic pressure.

Choroid plexus

Referred to as 'nerd gummies', it is produced by the pia mater and functions to produce CSF.

Arachnoid mater

The layer that absorbs and takes away all waste from the CSF.

Blood brain barrier (BBB)

A 'bouncer' that regulates what enters the brain; it is made of ependymal cells, tight junction cells, and astrocytes.

Astrocytes

Support cells that are critical in forming the blood brain barrier.

Tight junctions

Structures in the BBB that keep water-soluble channels out unless the brain specifically needs them.

Lipid soluble molecules

The 'VIP' molecules that easily slide through the phospholipid bilayer to enter the brain; this is primarily how drugs are moved into the brain.

Blood CSF layer

An alternative entry point to the brain where particles that get through unchecked go straight to the brain.