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Lecture 3

Course Code
Ted Petit

of 5
PSYB65H3 Lecture 3 (Sept 27, 2010)
Exam Format
Information from lecture + Information from textbook (even if he doesnt talk about
No dates
Will not ask any questions that are in a table (those that are not in textbook) , only
the text from the textbook
Midterm Exam Date: (Monday) November 1, 5-7pm
Exam is multiple choice
Main Teaching Points:
1.Things that go wrong with the nervous system eg. Stroke, traumas
2.Glial Cells and diseases that pertain to glial cells
Problems in Vascular System (Blood Flow)
Blockage in blood flow = lack of oxygen and glucose (critical)
Brain has high metabolic rate, a short period without oxygen is devastating
Brain damage
A.Types of Blockage of Blood flow
1.Cerebral Vascular Accident (CVA)
Most commonly called as stroke
Severe interruption of blood supply to the brain
Interruption of blood supply result in ischemia problem in blood supply, not
enough blood
oNot enough blood supply = not enough glucose and oxygen supplied to
the brain
Produces dead / dying tissue (infarct)
oInfarct tissue that is very damaged and has a lot of dying tissue 2
Lack of blood supply but very slow
Not rapid, very slow blockage in which blood vessels slowly breakdown
Result of very slow reduction in blood supply to the brain
Results in softening of the brain tissue getting some dead in the brain tissue
or swelling but death is not complete
3.Transient Ischemic Attack (TIA)
Sudden lack of oxygen that is temporary
Usually involves a typical musculature vessel
Eg. Migraine headaches
During constriction, there is a lack of blood supply to a particular part of the
Short duration comes and goes
Causes that result in disruption in blood flow
PSYB65H3 Lecture 3 (Sept 27, 2010)
Thrombosis locally formed blockage
oBlood clot can form at a single spot in the brain
Embolism a blockage that breaks off from someplace else
oA clot can break off from somewhere and become lodged at another
Arteriosclerosis general clogging of the arteries
oSlow reduction in blood supply results in encephomalacia
oHarding of the arteries (slow process)
B.Types of Blood Vessels Bursting
1.Cerebral Hemorrhage
Massive bleeding into the brain tissue itself
Busted blood tissue that is bleeding into the brain tissue itself
Can be life threatening
It is most often associated with high blood pressure
Cerebral hemorrhage kills the tissue where the bleeding is
2.Subdural Hematoma
Bleeding into the space between the skull and the brain itself
Bleeding underneath the dura mater (in Subaranoid space, where the vessels
are) bleeding outside the brain (in the meninges)
Doesnt kill the brain tissue itself directly if caught on time; causes pressure
on the brain
oIf caught in time, pressure can be released and no brain damage will
A collection or mass of enlarged abnormal blood vessels that can shunt blood
in the wrong direction
Blood vessels are inherently weak; if under high pressure, it can burst
(leading to a stroke)
Usually congenital
Vascular dilation - expanded blood pressure caused by localized problems in
Generally has no symptoms
Can result in hemorrhage
Slide 1
Subdural Hematoma
Bleeding has occurred in skull; pressure is pushing the brain way over (deforming
the brain)
Release of pressure can be done by drilling a hole in the skull to release the blood
Closed Head Injuries
PSYB65H3 Lecture 3 (Sept 27, 2010)
A blow to the head that causes an injury to the brain but doesnt actually open up
the head itself
Contracoup Effect someone whos come from a head injury; the possibility that the
other side of the brain may be affected from the damage of one side of the brain
(because brain is floating in CSF)
Brain Tumors
Caused by cancer a mass of growing tissue that is growing independent of the
surrounding tissue
Cancer of glial (helper) cells
Accounts for 45% of all brain tumors
Range from benign (not invasive) to highly malignant (will divide and
spread and infiltrate to other parts of the body)
Tumors formed in the meninges
Generally benign not threatening
Puts pressure on the brain (like subdural hematoma); not inside brain
If removed in time, usually not a problem
Slide 2
Shows common head injuries car accidents
Damage to front portion of the brain
Slam the brain to the front of the skull, or damage to temporal lobe on each side
Slide 3
Cancer down the centre of the brain
Slide 4
Brain Cancer in brainstem will kill the person because brain stem is not operable
(can only do chemotherapy)
Slide 5
Brain Cancer
Slide 6
Left: Cancer in cerebral cortex wont kill the person; probably just lost function in
Right: Cancer in thalamic area
Slide 7
Meningioma putting pressure on the brain but not in the brain; removal of tumor
will cure person
Infections of the Brain
Relatively rare, but can be very important
Infections that makes its way into the brain will cause inflammation and swelling
Encephalitis inflammation of the brain