Blood-Brain Barrier, Cerebrospinal Fluid and Ventricles

Epidural hematoma

(i.e., accumulation of blood in the potential space between dura and bone) may be intracranial (EDH) or spinal (SEDH)

what percent of csf is made in the lateral ventricles

95% of the CSF is produced in the lateral ventricles, and 5% is produced by the 3rd and 4th ventricles CSF is produced at ~1500 ml/day, yet the ventricles only hold 120-150 ml at any one time, so there is a 10 fold turnover rate Fetal choroid plexus is proportionally larger than that of the adult brain and fills more of the space in the ventricles

Meningeal Tumors

: are benign, well-circumscribed , slow-growing tumors; 90% of meningiomas are supratentorial

Brain lymphatic system

A brain drainage system - Brain scans of healthy volunteers showed that our brains may drain waste through lymphatic vessels, the body's sewer system. ... In most of the body they run alongside blood vessels. They transport lymph, a colorless fluid containing immune cells and waste, to the lymph nodes.

Hydrocephalus ex vacuo

Appearance of increased CSF in atrophy. Intracranial pressure normal, triad not seen. This Alzheimer's disease brain demonstrates mild to moderate cortical atrophy However, the most striking features are the large ventricles, particularly the third ventricle and inferior horns of the lateral ventricles An expansion of the ventricles due to tissue loss, as in this case, is termed hydrocephalus ex vacuo Ex-vacuo hydrocephalus, which occurs when there is damage to the brain caused by stroke or traumatic injury. This type of hydrocephalus may not be a health danger for some people, in which case treatment is not needed.

CSF flows from the choroid plexus (for instance) through the brain's blank, interconnecting ventricles before finally entering the sub-arachnoid space, which surrounds the brain and spinal cord The fluid then flows over the brain and spinal cord and is eventually absorbed into the venous blood system through tiny, one-way channels called blank blank

CSF flows from the choroid plexus (for instance) through the brain's four, interconnecting ventricles before finally entering the sub-arachnoid space, which surrounds the brain and spinal cord The fluid then flows over the brain and spinal cord and is eventually absorbed into the venous blood system through tiny, one-way channels called arachnoid granulations or villi

Cerebrospinal Fluid (CSF)

CSF is a watery broth of nutrients, ions and other essential molecules The CSF bathes the exterior of the CNS and fills the ventricles, the four large cavities inside the brain

. Normal-pressure hydrocephalus

CSF is not absorbed by the arachnoid vill Normal-pressure hydrocephalus, which usually develops in people who are age 55 or older. It is a potentially treatable cause of dementia. This type of hydrocephalus often occurs after head trauma, infections, and bleeding within the brain.i

CSF is synthesized in the blank blank the Virchow-Robin space and other brain sites As CSF flows, it exchanges molecules with the interstitial fluid between neurons

CSF is synthesized in the choroid plexus, the Virchow-Robin space and other brain sites As CSF flows, it exchanges molecules with the interstitial fluid between neurons

CSF moves from subarachnoid space to venous drainage though the blank blank

CSF moves from subarachnoid space to venous drainage though the Arachnoid Villi

Bacterial Meningitis Viral Meningitis

Characterized clinically by fever, headache, Nuchal rigidity and Kernig's sign Streptococcus Echovirus, Epstein-Barr virus, Herpes simplex type 2 virus

Cerebrospinal fluid Circulation

Circulates through system of channels: - ventricles: 3rd, lateral, 4th - subarachnoid space - spinal cord

Three cellular elements of the brain microvasculature compose the BBB

Endothelial cells Astrocyte end-feet Pericytes

Failure of arachnoid villi occurs in multiple patients Including and often in elderly and those with blank disease symptoms. This leads to Normal Pressure Hydrocephalus (discussed later).

Failure of arachnoid villi occurs in multiple patients Including and often in elderly and those with Alzheimer's disease symptoms. This leads to Normal Pressure Hydrocephalus (discussed later).

Fourth ventricle continues as the

Fourth ventricle continues as the central canal of the medulla (foramina of Luschka and Magendie) and spinal cord

Subfalcine (Cingulate) Herniation

Herniation below the falx cerebri (headaches, contralateral leg weakness)

The BBB is relatively impermeable However these dieasesase can get through HSC Brain hiv ms alz

Hypoxia-Ischemia Septic encephalopathy Cerebral edema Brain tumors HIV-associated dementia Multiple sclerosis Alzheimer's disease

Pseudo-tumor cerebri

Increased resistance to CSF outflow at the arachnoid villi

Adult Ventriculomegaly

Individuals with schizophrenia, including those who have never been treated, typically have enlarged ventricles in the brain, as demonstrated in over 100 studies to date enlarged ventricules

Meningitis:

Inflammation of the pia-arachnoid area of the brain, spinal cord, or both

Cerebrospinal Fluid Properties

It contains very small amounts of protein, sugar and K+ It contains large amounts of Na+ and Cl - Normal CSF has no cellular components in it, so a gram stain would be negative There is no substance found in CSF which is not also normally found in blood plasma, it is really no different from any other interstitial fluid It is an ultra-filtrate of blood

Large blank in the choroid plexus may obstruct the flow of CSF or compromise cerebral circulation by pressing against the brain parenchyma

Large tumors in the choroid plexus may obstruct the flow of CSF or compromise cerebral circulation by pressing against the brain parenchyma Example: benign adenoma manufactures too much CSF

The blood-brain barrier is present in all brain regions, except for the circumventricular organs: Mnpsoa

Median eminence Neurohypophysis Pineal gland Subfornical organ Organum vasculosum of the lamina terminalis Area postrema

Neurochemical and neuronal mechanisms involved in the emetic response and relevant receptors seem to be rather complicated relative to emetic stimuli It is well known that blank receptor agonists and L-DOPA are effective drugs for the treatment of Parkinson's disease. These drugs, however, frequently (approximately 30%) cause nausea and vomiting as unavoidable side effects by stimulating dopamine receptors in peripheral and brain tissues

Neurochemical and neuronal mechanisms involved in the emetic response and relevant receptors seem to be rather complicated relative to emetic stimuli It is well known that dopamine receptor agonists and L-DOPA are effective drugs for the treatment of Parkinson's disease. These drugs, however, frequently (approximately 30%) cause nausea and vomiting as unavoidable side effects by stimulating dopamine receptors in peripheral and brain tissues

Non-Communicating hydrocephalus

Obstruction within the ventricles Obstructive, or non-communicating, hydrocephalus occurs when the CSF does not flow properly between or out of the brain ventricles because of an obstruction, such as from a malformation or narrowing

Transforaminal (Tonsillar) Herniation

Protrusion of the brain stem and cerebellum through the foramen magnum (obtundation)

Transtentorial (Uncal) Herniation

Protrusion of the brain through the tentorial incisure (occulomotor CN III, paresis ipsilateral, dilated pupils)

Such adenomas may secrete from three to five times as much CSF as normal Over-secretion of CSF overwhelms the brain's mechanisms for reabsorbing the fluid The result is: blank

Such adenomas may secrete from three to five times as much CSF as normal Over-secretion of CSF overwhelms the brain's mechanisms for reabsorbing the fluid The result is: hydrocephalus

The above unprotected areas of the brain regulate blank nervous system and blank glands (e.g., the pituitary) of the body

The above unprotected areas of the brain regulate autonomic nervous system and endocrine glands (e.g., the pituitary) of the body

The arachnoid membrane and the pia mater are collectively referred to as the

The arachnoid membrane and the pia mater are collectively referred to as the leptomeninges

ventricular system

The cerebrospinal fluid-filled spaces inside the brain, consisting of the lateral ventricles, third ventricle, cerebral aqueduct, and fourth ventricle.

The paired lateral ventricles communicate with the third ventricle through the

The paired lateral ventricles communicate with the third ventricle through the interventricular foramina (foramina of Monro)

The third ventricle communicates with the fourth ventricle through the

The third ventricle communicates with the fourth ventricle through the cerebral aqueduct (aqueduct of Sylvius)

These pathological insults can alter the integrity of the BBB with consequent migration of blankinto the brain parenchyma Leukocytes: blank(lymphocytes and monocytes), Granulocytes (neutrophils and basophils)

These pathological insults can alter the integrity of the BBB with consequent migration of leukocytes into the brain parenchyma Leukocytes: Agranulocytes (lymphocytes and monocytes), Granulocytes (neutrophils and basophils)

A 5-year-old boy presents to your office with fever, headache, nuchal rigidity and positive Kernig's sign. Cerebral spinal fluid profiles show numerous polymorphonuclear leukocytes, decreased glucose levels and increased protein levels. What is the most likely diagnosis? A. Bacterial meningitis B. Septic encephalopathy C. Subfalcine herniation D. Transforaminal herniation E. Viral meningitis

a

Blood-brain barrier disruption is present in: A. Multiple sclerosis B. Serotonin syndrome C. Grave‟s disease D. Addison‟s disease E. Autism spectrum disorders

a

The specialized structure that projects into the lateral, third and fourth ventricles of the brain is: A. The choroid plexus B. Astrocyte end-feet C. Crus cerebri D. Optic chiasm E. Median foramen (of Magendie)

a

The third ventricle communicates with the fourth ventricle through the: A. Cerebral aqueduct B. Interventricular foramina C. Central cana D. Subfornical organ E. Median eminence

a

area postrema

a region of the medulla where the blood-brain barrier is weak; poisons can be detected there and can initiate vomiting

Hydrocephalus

accumulation of fluid in the spaces of the brain

The dura mater:

also called the pachymeninx Inner portions of the dura mater give rise to septa such as the falx cerebri or tentorium cerebelli

Which of the following regions lack the blood-brain barrier? A. Amygdala B. Organum vasculosum of the laminal terminalis C. Hippocampus D. Habenula E. Nucleus accumbens

b

Communicating hydrocephalus

blockade of subarachnoid space Non-obstructive, or communicating, hydrocephalus occurs when the CSF flows out of the chambers of the brain (ventricles) and into the spinal canal, but it is not reabsorbed normally by the tissue surrounding the brain and spinal cord. Sometimes this type of hydrocephalus corrects itself.

cells in order of blood (most medial)

blood, endothelial cell, pericyte, basebement membrane, perivascular astrocyte endfoot

Which of the following is a circumventricular organ: A. Hippocampus B. Amygdala C. Area postrema D. Caudate putamen E. Septum

c

A subdural hematoma

develops when the tiny veins that run between the dura and the surface of the brain (bridging veins) tear and leak blood This is usually the result of a head injury

meninges of brain

dura mater, arachnoid mater, pia mater

Cerebrospinal fluid (CSF) is produced by the __________ and absorbed by the ___________ that protrude into the venous sinuses A. Subarachnoid space; dura mater B. Epidural space; pia mater C. Fourth ventricle; central canal D. Interventricular foramen of Monro; third ventricle E. Choroid plexus; arachnoid granulations or villi

e

Detection of red blood cells in the cerebrospinal fluid could indicate: A. Aseptic meningitis B. Herniation or coning C. Meningeal tumor(s) D. Rhinorrhea E. Subarachnoid hemorrhage

e

These tumors are benign, well-circumscribed, slow growing tumors. They account for 15% of primary intracranial tumors and are more commonly diagnosed in females than males (3:2). In addition, ninety percent of these tumors are supratentorial: A. Astrocytoma B. Ependymoma C. Glioblastoma multiforme D. Medulloblastoma E. Meningioma

e

what cells form tight junctions

enthotelial cells

meningeal layers

epidural (between bone and dura) external cartoid branch across the top of the dura dura sudural space arachnoid subarachnoid space (this is the space where all of the cerebral arteries are located, anterior and posterior blood supplies meet at the base of the brain in the circle of willis) pia brain

Emesis

is an instinctive defense reaction caused by the somato-autonomic nerve reflex, which is integrated in the medulla oblongata

A brain herniation

is when brain tissue, cerebrospinal fluid, and blood vessels are moved or pressed away from their usual position in the head A brain herniation occurs when something inside the skull produces pressure that moves brain tissues This is most often the result of brain swelling from a head injury

tight junctions

present between the cerebral endothelial cells, form a diffusion barrier, which selectively excludes most blood-borne substances from entering the brain

pericyte

stem cell that regenerates smooth muscle cells

Astrocyte

type of glial cell that transports water and salts from capillaries They perform many functions, including biochemical support of endothelial cells that form the blood-brain barrier, provision of nutrients to the nervous tissue, maintenance of extracellular ion balance, and a role in the repair and scarring process of the brain and spinal cord following traumatic injuries.

-emesis

vomiting

The blood-brain barrier (BBB) is a diffusion barrier function

which impedes influx of most compounds from blood to the brain parenchyma