PSYB65 chapter 14.docx

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Published on 15 Jun 2012
School
UTSC
Department
Psychology
Course
PSYB65H3
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Chapter 14
- Tumor: mass of new and abnormal tissue that is not beneficial
o Also called neoplasms “new tissue”
o Space occupying lesions, foreign objects that cause damage to CNS.
- Brain most common site, uterus second.
- Tumors differ in growth rate, whether they infiltrate or stay encapsulated, or how likely
to recur if removed
- Benign: won’t recur
- Malignant: more likely to recur
- 3 major types of brain tumours: originate from glial cells, the meninges, nervous tissue,
or other parts of the body already infected with a tumor
o From glial cells gliomas
Astrocytomas: from astrocytes. Grow slowly and rarely malignant.
Causes compression of surrounding tissue. Some infiltrate surrounding
tissue. Usually surgically removed unless it’s inaccessible
Glioblastoma: grow quickly, highly malignant. Infiltrates surrounding
tissue. Hard to surgically remove chemotherapy is often treatment
instead
Medullablastoma. Highly malignant, forms around cerebellum and
brainstem early in life so it affects vegetative functions. Prognosis is
poor. Chemotherapy best option
o From meninges
Meningiomas: gorow out from meninges. From dura mater. Outside of
CNS therefore well encapsulated. Harmful when pressure applied from
tumor. Relatively benign. Surgery best treatment
o Metastatic tumors: secondary tumors from migrated tumor. Can be lungs,
breasts, uterus, kidneys. More common for original tumor to be located outside
of CNS
Simple metastatic: one tumor
Multiple metastatic tumors: more spread from lungs to CNS.
Surgical or radiological treatment. If multiple, than whole brain
radiotherapy or chemotherapy
Prognosis poor
- Neuropsychological effects: small slow infiltrating astrocytoma in primary visual cortex
can slowly cause nlndness in part of visual field. Same with tuomrs of pituitary gland
because its close to optic chiasm
- Rapid meningioma that is encapsulated can apply pressure to primary motor and
sensory corticies causing paresis and numbess to feet and legs
- Metastatic tumors in left temporal lobe = speech distruabnces, left parietal lobe =
apraxia. Tumors can also cause epileptic seizues and release substances toxic to brain. If
in ventricles it can be spread
Cerebrovascular disorders
- When blood supply is interrupted
- Leading cause of disabling neurological damage. Third most common cause of death in
developed world (first is cancer, then heart attack and these lead to neurological
damage)
- CVA (cerebrovascaular accident) aka stroke. Interruptions to brain’s blood syupply. Can
be sudden or gradually can result in
o Cerebral ischemia: lack of blood supply to brain.
o Severe cerebral iscehma is an infarct.
o If it’s in major vessel result can be large like heart attack
o Cause can be from blocked arteries, broken arteries or interruption of blood
supply outside
- Thrombosis: blood clot in cerebral blood vessel. Can form outside brain. If in heart
causes heart attack
o Common cause is atherosclerosis: fatty deposits build up inside walls of blood
vessels constricting it more and more. Gradually, symptoms appear gradually.
o Bifurcation: blocks artery that branch off. Therefore affect is is large and results
in disorder that are usually diffuse and gradually
- Embolism: also blocking of artery by buildup. A clot that travels in bloodstream from
one part of body to another (where vessel is smaller therefore is blocked). Often sudden
and complete. Extremely dangerous if not removed immediately. Treated surgically or
with anticoagulant drugs
- Hemorrhage: bursting of blood vessel. Can be from aneurism (weak spot of vessel) or
too much pressure from an embolism or thrombosis, or piercing foreign object, or
hypertension/high blood pressure
o Blood is somewhat toxic to neural tissue and loss of oxygen and glucose supply
o Bleeding can compromise brain regions. Pressure can become displaced to
neural centers critical for basic vegetative functions.
Intracerebral hemorrhage: hemmorrhage in brain. Usually from
hypertension and results in interupition of blood flow, toxicity of
uncontained blood and pressure build up. Unlikely to recur. Prognosis is
poor
Subarachnoid hemmorhage: blleding into subarachnoid space. Also
from hypertension. Pressure causes headache, nausea vomiting, loss of
consciousness. Influence many different structures. Also poor prognosis
- Some CVAs caused by physical defects in cerebral vasculature. Maybe be congenital, or
physical trauma
- Arteriovenus malformation (AVM): malformed arteries and vessels. Extra or missing
connections. Tend to form in middle cerebral artery
o Bleeds regularly but small amounts over long periods of time. Damage results in
lack of irrigation of a particular area acoupled with toxicity of blood
- Aneurysm: area of artery that dilates because of weakness. Balloon like expansion.
o Can burst, blooed, or not produce problem
o Prognosis could be good because of surgery, but if it suddenly bursts it can lead
to intracranial hemorrhage and can be fatal but rare.
o AVM treatment depends on medical history too. if surgically inaccessible, may
use drugs to alter blood pressure, but can’t if they already have low blood
pressure
o Surgical treatment questionable. May do more harm? Can be clipped and not
magnetic so you can use MRI. Older types of clips vulnerable to magnetic fields
o Draining can also be used as treatment
o Surgery can remove or rbeak thromboses or embolisms.
o Antigoagulant drugs can e used but risks starting bleed that can’t be controlled
Head injuries
- Traumatic brain injury (TBI) leading cause of closed head injury. 0-% of head injuries
- Does not include congenital disorders or birth trauma
- Not all brain damage occurs as result of initial accident.
- Young people 15-24 are highest risk for TVI. Older people more serious symptoms. Men
more likely than women.
- Those who survive di not have greater risk of mortality
- Disabilities can reduce individual’s independence and work
- Many TBI recover within weeks so no examiniation of cognitive functions
- 15% mild TBI patients still disabled year after
- Primary symptom is cognitive impairment.
- Effects of TBI reflect most severe injuries
- Common impairments: sexecutive skills, short term memory, concentration, difficulty in
well=known tasks when there are small deviations from normal routine (can’t transfer
learning). Normal intelligence however but may be incapable of independent living.
- Closed head injury: nlow to head but doesn’t penetrate skull
- Open head: penetrates skull. Not always worse. Causes lesions and neurosurgery can
saved. Does not lose consciousness, damage is localized
- Closed head injury more damage because the coup (point of impact) leads to brain
bouncing off skull producing contre-coup injury. Can lead to displacement, shearing of
brain from skull’s protrusions (fossae), build-up of blood, sudden loss of consciousness,
widespread areas of brain affected.
Infections
- Usually infections spread from other sistes outside the CNS. Eg. The nose or ears.

Document Summary

Tumor: mass of new and abnormal tissue that is not beneficial: also called neoplasms new tissue , space occupying lesions, foreign objects that cause damage to cns. Tumors differ in growth rate, whether they infiltrate or stay encapsulated, or how likely to recur if removed. 3 major types of brain tumours: originate from glial cells, the meninges, nervous tissue, or other parts of the body already infected with a tumor: from glial cells gliomas. Hard to surgically remove chemotherapy is often treatment instead. Highly malignant, forms around cerebellum and brainstem early in life so it affects vegetative functions. Surgery best treatment: metastatic tumors: secondary tumors from migrated tumor. More common for original tumor to be located outside of cns. Multiple metastatic tumors: more spread from lungs to cns. Neuropsychological effects: small slow infiltrating astrocytoma in primary visual cortex can slowly cause nlndness in part of visual field. Same with tuomrs of pituitary gland because its close to optic chiasm.