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