Egleton - Ventricles Flashcards
What is the third ventricle associated with?
Hypothalamus
What type of cells are neurons?
What is a consequence of this?
Post-mitotic, if they die they are not replaced
Cranial Dura
Outermost layer, adherent to inner surface on the cranial bone
Outer layer Not continuous with dura of spina cord
Dural Septa function?
Provide support and protection for the brain
Helps protect against suddent, violent movements
More common in children and adults–
Infratentorial and Supretentorial Tumors?
Infratentorial tumors more common in children
Supratentorial tumors more common in adults
Clinical: Dural venous sinuses and impact on brain?
Venous sinuses return CSF to systemic circulation
If they become damaged, fluids won’t move and pressure can build up
Clinical: Lesions and the Great Cerebral Vein of Galen?
Supretentorial space-occupying lesions can cause this vein to be compromised and block venous flow or cause a compression hemorrhage
Clinica: Infection and the Cavernous Sinus?
Receives blood from the face, anastomoses can cause infections to spread to the CNS
Sub-Arachnoid Space
CSF is distributed here
All major blood vessels of the brain lie in the subarachnoid space
Cisterns
Four major?
CSF pools in there areas
- Cerbellomedullar Cistern
- Pontine Cistern
- Interpeduncular Cistern (major area for CSF), Circle of Willis lies here
- Lumbar Cistern, area where spinal tap taken here
Arachnoid Villi
Penetrations of Arachnoid into the venous sinuses, allow for passage of CSF back into general circulation
May become calcified and visible in brain scans (normal)
Pia
Inner most layer, in elderly CSF can pool in Virchow Robin space, and appear as “bright spots” on T2
Separation of two lateral ventricles?
Septum Pellucidum
What connects lateral ventricles to the third venticle?
What forms the walls of the third ventricle?
What connects to the fourth ventricle?
Intraventiricular Foramen of Monro
Walls of Thalamus and Hypothalamus
Cerebral Aqueduct of Sylvius
What forms the boundaries for the fourth ventricle?
Cerebellum (roof)
Pons/Medulla (floor)
Pineal Body
Melatonin
Circadian rhythms
Organum Vasculosum of the Lamina Terminalis
Measure Sodium
Neurohypophysis (Pituitary Gland)
Endocrine Organ
Oxytocin, Vasopressin
Area Postrema
Chemoreceptor trigger zone (vomit center)
Hydrocephalus
Non-communicating vs Communicating
Excess CSF
Non-communicating: blockage of fluid flow in ventricle, commonly Aqueduct of Sylvius, usually secondary to another disorder, shunt treatment
Communicating: Too much CSF is produced, or not enough removed. Head may swell, can damage brain. May destroy choroid plexus, or reduce CSF w/meds
CSF Color:
Clear
Pink or Red
Yellow and Clots Spontaneously
Cloudy or White
Clear to Slightly Cloudy
Clear: Normal, sterile
Pink or Red: Blood, Circle of Willis bleed
Yellow and Clots Spontaneously: Increased protein, chronic inflammation (ex. M.S.)
Cloudy or White: Bacterial Meningitis, High protein, low glucose
Clear to Slightly Cloudy: Aseptic Meningitis, Normal protein, glucose; viral
Compensated and Uncompensated Mass?
Large mass lesions can increase Intracranial Pressure (ICP0 by compression, comprimized blood flow, or herniation of brain
Herniations:
- Subfalcine
- Uncal
- Pressure Coning
Uncal - Uncus of Temporal Lobe into tentorial notch
Compression of crus cerebri, motor weakness in either side, decreased consciousness, pupillary dilation on ipsilateral side of herniation
- - - -
Pressure Coning - Cerebellat tonsil into Foramen Magnum
Very decreased consciousness, change in vital signs
Clinical: Sbarachnoid Hemorrhage
Crab of Death!
Pink or red CSF
Most common burst berry aneurysm in Circle of Willis (Anterior part)
Symptom: Sudden onset of severe headache, stiff neck, altered consciousness
Clinical: Fractures at base of skull
Usually more life threatening
Symptoms: May leak CSF from nose, bleed from auditory canal
High risk of infection
Clinical: Epidural Hemorrhage
Biconvex disc on CT/MRI
Middle Meningeal Artery
Herniation possible
Clinical: Subdural Hemorrhage
Bleeding into subdural space between dura and the arachnoid
Not bound by suture lines
Crescent-shaped hematomas
Tear of bridging veins, more common in elderly
CTE (Chronic Traumatic Encephalopathy)
Caused by repeated head trauma, TBIs
Memory loss, paranoid, depression, ataxia
Clinical: Neonatal and Pediatric Hydrocephalus
Mothers infected with mumps or rubella virus (inflammatory adhesions form and obstruct flow of CSF)
Non-Communicating in Newborns may swell head
Can be fatal!
**Clinical: Idiopathic Intracranial Hypertension**
Increased ICP w/no apprent cause
Signs:
Elevated opening pressure in LP
Pulsatile headaches
Visual disturbances
Risk:
Obese woman
Vitamin A excess
Estrogen birth control
Treatment:
LP, Drugs to lower CSF, Alter meds
Lose weight
Clinical: What type of drugs are used to alter CSF production?
Inhibit Carbonic anhydrase activity
Reduces activity of bicarb dependent co-transporters
Clinical: Normal Pressure Hydrocephalus (NPH)
Seen in elderly adults
Type of communicating hydrocephalus
May or May Not have increase in ICP
Imbalance in CSF production / reabsorption
Three Major Signs: Gait difficulty, Cognitive disturbance, Urinary incontinence (NO headache, nausea, vision, papilledeme)
Treatment: Shunt
