Ventricular System of the Brain
spatial, removes
2 more functions of CSF: ______ buffer and ________ unwanted substances away from the CNS
1. anterior (frontal) horn 2. body: located in the frontal and parietal lobes 3. posterior (occipital) horn 4.inferior (temporal horn) 5. atrium: where body and posterior horn meet
5 basic components of each lateral ventricle:
increased intracranial pressure
ICP has a variety of causes: cerebral edema, brain hemorrhages or tumors, CSF volume increase, venous obstruction causes increase in blood volume
stable ionic
a function of CSF: provides _______ ______ environment for the CNS
suspended
a function of the CSF is to provide an environment for the brain and spinal cord to be __________
central canal
a small canal that extends caudally throughout the spinal cord
medial aperture
aka foramen of Magendie; one of these
lateral apertures
aka foramina of Luschka; two of these
3 apertures
blocked circulation of CSF may result from a failure of the ___ ________ of the 4th ventricle to form during development (all ventricles hydrocephalic)
specialized epithelial cells
choroid plexus is formed from _________________
impeded reabsorption of CSF
cogenital absence of arachnoid villi -rare -all ventricles hydrocephalic
hydrocephalus
dilation of the ventricles; puts pressure on surrounding brain tissue
third ventricle
formed by the surface of thalamus (laterally) and hypothalamus (ventrally)
lateral, third and fourth
four cavities make up the ventricles:
1. excess production of CSF 2. blocked circulation of CSF 3. impeded reabsorption of CSF
hydrocephalus can result from 3 issues:
communicating (non-obstructive), non-communicating (obstructive)
hydrocephalus is clinically subdivided into:
brain herniation
if ICP is left untreated, may cause ____ _____ (brain fills up cranial cavity so it moves through foramen magnum or other brain areas for more space)
subarachnoid, dural venous sinuses
in the pressure gradient system, the pressure is higher in the ___________ space compared to the pressure in the _______ ______ _______ so CSF flows from area of high pressure to an area of low pressure
choroid plexus
invagination of vascular pia mater
cerebral aqueduct
is relatively long, narrow and easily blocked
treatment of ICP
may include: sedatives and paralytics, extraventricular drains and bolts, craniotomies
mechanical
movement of CSF is pulsatile as arteries pulsate
choroid plexus
produces CSF and is present in each ventricle
-headache -nausea and vomiting -bradycardia -hypertension -loss of consciousness
symptoms of ICP
pyramid
the fourth ventricle is ______ shaped
cerebellum
the fourth ventricle is located posterior to pons and upper part of medulla and anterior to the _____________
diencephalon
the third ventricle is considered a midline slit of _________
buoyancy
to reduce traction on nerves and blood vessels
hydrocephalus treatment
treated by addressing the cause and shunting
blocked circulation of CSF
tumors may cause this: 1. tumor near one interventricular foramen (one enlarged lateral ventricle) 2. pineal gland tumor can occlude (block) cerebral aqueduct (enlarged lateral and 3rd ventricles)
papillomas
tumors of choroid plexus: sometimes causes increased CSF production and hydrocephalus. Results in all ventricles being hydrocephalic
lateral ventricles
two of these, one in each hemisphere
blocked circulation of CSF
-circulation obstructed outside the ventricular system (subarachnoid hemorrhage or meningitis) -Arnold-Chiari malformation (parts of cerebellum and medulla displaced through foramen magnum blocked CSF flow; associated with spina bifida) =all ventricles being hydrocephalic