Question

radiographic pathology for technologists

Chapter 8: CENTRAL NERVOUS SYSTEM Answer the following questions with a short answer (2-3 sentences). • Please submit only the answer portion of this exercise to the instructor. • Make sure to number your answers. 1. Where is CSF manufactured and absorbed? Explain the physiologic basis for the development of hydrocephalus. 2. Why is MRI the modality of choice for demonstrating diseases in the posterior fossa? 3. What is the most common cause for CVA and the most common site for it to occur? 4. What are the major differences between meningitis and encephalitis? 5. Explain the differences between glial and nonglial tumors, and give an example, of each type.

Answer 1

1. The choroid plexus of each ventricle produces CSF. CSF flows through the ventricles and into the subarachnoid space via the median and lateral apertures. CSF flows through the subarachnoid space. CSF is absorbed into the dural venus sinuses via the arachnoid villi (granules).

CSF is blocked, does not get absorbed into blood propery, brain makes too much, can also be caused by genetic defects, certain infections during pregnancy. Also caused by infections to CNS, bleeding into brain soon after delivery (esp premature babies), injury before during or after childbirth, tumors of central nervous system, injury/trauma

3. Commonest type of CVA :-

1. ischemic-type stroke

-involves OCCLUSION OR BLOCKAGE of a blood vessel

-death of brain tissue occurs due to the inadequate supply of blood and oxygen to the brain

-two main types thrombotic and embolic

2. hemorrhagic-type stroke

-occurs when a weakened blood vessel in the brain BURSTS OR RUPTURES causing bleeding into the brain

-blood is spilled into surrounding structures and brain tissue compressed and displaced

3. thrombotic stroke

-the most common cause of CVA (nearly 60% of all strokes) is due to a thrombus (blood clot)

-these clots usually form around atherosclerotic plaques

-blood flow is blocked to a part of the brain and causes brain cells in that area to stop functioning and die

-blockage of the artery is gradual, therefore onset of symptoms may be slower

4. embolic stroke

-embolism-moving clot that forms somewhere in the body and eventually occludes a blood vessel to the brain

-emboli may arise from the heart or other blood vessels

-atrial fibrillation is a common precursor to this type of stroke

-the emboli will travel the bloodstream until they become lodged and cannot travel any further

#. The most common site of CVA is MCA

4. The major difference between meningitis and encephalitis :-

Meningitis - inflammatory disease of the leptomeninges ( arachnoid and piamater )

Encephalitis is the inflammation of the brain , mostly caused due to viral infection .