Download Cerebrospinal Fluid: Production, Circulation, and Functions and more Quizzes Philosophy of psychiatry in PDF only on Docsity!
What are ventricles?
spaces within the brain that are filled with cerebrospinal fluid (CSF). TERM 2
Where is CSF secreted?
DEFINITION 2 actively secreted by a specialized epithelium using blood plasma as a primary resource for material TERM 3
CSF circulation path
DEFINITION 3 circulates through the ventricles and subarachnoid space to eventually return to the venous system TERM 4
What is the purpose of the CSF fluid
circulation?
DEFINITION 4 circulation of fluid provides a second mechanism for fluid exchange within the brain similar to lymphatic circulation peripherally TERM 5
Anatomy of the ventricles
DEFINITION 5 4 ventricles are interconnected that include: Two lateral ventricles in the cerebral hemispheres. A third ventricle in the midline between the two halves of the diencephalon. A fourth ventricle between the cerebellum and brainstem.
What cells line the ventricles?
The surfaces of the ventricles, including the spinal central canal are lined with simple cuboidal neuroglial cells, the ependyma TERM 7
What do ependyma
do?
DEFINITION 7 The ependyma form an epithelial lining for the ventricles which is permeable to fluid exchange with brain tissue. TERM 8
Specialized areas of ependymal cells are
what?
DEFINITION 8 specialized areas of ependymal cells (choroid plexus) produce cerebrospinal fluid. TERM 9
The exchange or flow of extracellular fluid
from brain tissue through ependymal lining of
the ventricles is somewhat similar to what?
DEFINITION 9 the lymphatic system peripherally (the brain has no lymphatic system). TERM 10
where is the choroid plexus located?
DEFINITION 10 Most of the choroid plexus is in the lateral ventricles, to a lesser extent in the third and fourth ventricles.
The junction between the lateral ventricles
and the third ventricle?
the interventricular foramen (Foramen of Monro TERM 17
Cerebral aqueduct
DEFINITION 17 The cerebral aqueduct communicates between the third and fourth ventricles in the midbrain TERM 18
From the fourth ventricle, cerebrospinal fluid
moves how?
DEFINITION 18 into the subarachnoid space through 3 openings TERM 19
What is the lateral opening through which the
CSF flows from the 4th ventricle?
DEFINITION 19 The lateral openings are the foramina of Luschka (2) allow CSF to flow laterally out of the 4th ventricle TERM 20
Foramen of Magendie
DEFINITION 20 a single midline foramina under the vermis of the cerebellum
How does CSF flow beyong the ventricles?
From the three foramina in the fourth ventricle, cerebrospinal fluid moves out of the ventricles and out over the entire surface of the brain (and spinal cord)in the subarachnoid space TERM 22
Subarachnoid space
DEFINITION 22 The subarachnoid space, is a space between the arachnoid mater and pia materThis space also contains surface vessels of the brain TERM 23
The brain and spinal cord are therefore
essentially suspended in CSF by what?
DEFINITION 23 the arachnoid trabeculae (connective tissue filaments between the arachnoid and pia). TERM 24
Subarachnoid cisterns
DEFINITION 24 are naturally expanded regions of the subarachnoid space that contain CSF, arteries and veins and in some instances, cranial nerve roots TERM 25
How are subarachnoid cisterns named?
DEFINITION 25 The cisterns are usually named according to their adjacent structuresThe shapes of these cisterns are often useful in MRI and CT scans because of their relationships to brain structures
CSF volume compensation
When the heart beats, cerebral vessels expand with the increase in arterial pressure. This causes an increase in vascular volume within a closed space, the cranial cavity. This volume change is compensated by an increased outflow of CSF into the dural sinuses. Obstruction in the normal flow can produce changes in the pattern. TERM 32
Normal pressure of CSF
DEFINITION 32 is 50-180 mm of H2O and is to some extent regulated by venous pressure TERM 33
How is CSF pressure and composition
measured or sampled?
DEFINITION 33 with a spinal tap needle into the lumbar cistern. The pressure of CSF varies with the pulse and respiration because both of these processes affect venous backpressure TERM 34
Normal appearance of CSF
DEFINITION 34 ClearColorlessHas very little proteinHas very few cellsIonic composition is similar, but not identical to blood plasmaAlteration of these properties can be an indicator of disease states TERM 35
Indications of
infection
DEFINITION 35 Cloudiness or increases in immune-related cells can indicate infection. (-gitis)Yellow =Blood breakdown products Hyperbilirubinemia
Bacterial meningitis
can spread rapidly because of the CSF flow in the subarachnoid space.Because the infection spreads in the region of CSF flow, CSF is usually cloudy with many white blood cells, increased protein and bacteria. TERM 37
symptoms of bacterial meningitis
DEFINITION 37 symptoms include elevated temperature, alternating chills and fever, headache and patients may have a depressed level of consciousness. Rapidly progressing disease can result in death within 2 days. TERM 38
CSF disturbance and increased intracranial
pressure
DEFINITION 38 If CSF is prevented from circulating back into the venous sinuses it will build up pressure (intracranial pressure aka hydrocephalus). This can enlarge one or more of the ventricles, usually at the expense of vascular space (veins) if it occurs quickly and white matter over longer periods of time TERM 39
signs of increased intracranial pressure
DEFINITION 39 include headache, changes in mental status with altered level of consciousness, papilledema, and sometimes projectile vomiting TERM 40
Papilledema
DEFINITION 40 Edema or bulging of the optic papilla (disk) with increased CSF pressue is due to the fact that CSF also runs along the dura and connective tissues of the cranial nerves, notably the optic nervesThis allows for elevated CSF pressure to be transferred to the back of the eye resulting in papilledema
Communicating hydrocephalus
the flow of CSF through the ventricles and subarachnoid space is not impaired, but the movement of CSF into the venous system is totally or partially blocked TERM 47
causes of communicating hydrocephalus
DEFINITION 47 the congenital absence of arachnoid villi, blockage of villi by subarachnoid hemorrhage, or infection. CSF can also be over produced usually as a result of a choroid plexus tumor TERM 48
Both forms of hydrocephalus can result in
what?
DEFINITION 48 increased intracranial pressure and ventricular expansion TERM 49
Normal pressure hydrocephalus may develop
when?
DEFINITION 49 after chronic meningitis, subarachnoid hemorrhage, or disease of the base of the skull that produces compression. TERM 50
cause of normal pressure hydrocephalus
DEFINITION 50 Often the cause is unknown, but usually, it is related to a disruption of arachnoid granulations. The ventricles may be initially enlarged and CSF pressure elevated, but the pressure may wax and wane over time and remain at a high normal level
symptoms of normal pressure hydrocephalus
Symptoms may include urinary problems (frequency, urgency, or incontinence), impaired gait (ability to step up on a curb, apraxic gait-no weakness, but difficulty) and dementia. NPH can mimic Alzheimers and Parkinsons disease. TERM 52
Treatment for hydrocephalus
DEFINITION 52 The typical treatment for persistent increases in intracranial pressure is the placement of a shunt into a lateral ventricle with a drain into the peritoneal cavity.
