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Chapter 15

PSYC 211 Chapter Notes - Chapter 15: Amyloid Precursor Protein, Glatiramer Acetate, Basal Ganglia

Course Code
PSYC 211
Yogita Chudasama

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Chapter 15: Neurological Disorders
Notes taken by: Ashley Brown
Contact for mistakes: Ashley.brown@mail.mcgill.ca
These notes probably suck (esp. near the end) and a lot of the time are essentially
copied straight from the book (10th edition btw) because I kind of just stare and take
notes at the same time, so they contain not the most brief of statements but yeah… I
still feel like I owe docuum a set of notes for saving my butt every exam. Enjoy,
happy studying, and hope these help!
The major categories of neuropathological conditions that the brain can sustain are:
tumours, seizure disorders, cerebrovascular accidents, disorders of development,
degenerative disorders, and disorders caused by infectious diseases
Tumour: a mass of cells whose growth is uncontrolled and that serves no useful function
- malignant tumour: a cancerous tumour, it lacks a distinct border and may
- benign tumour: a noncancerous tumour, it has a distinct border and cannot
- the major difference between the two is whether the tumour is encapsulated or
has a distinct border between the mass of tumour cells and surrounding tissue
Metastasis: the processes by which cells break off tumours, travel through the vascular
system, and grow elsewhere in the body
Tumours damage brain tissue by two means: compression and infiltration
- both benign and malignant tumours can cause damage by compression
because they occupy space and push against the brain either destroying brain
tissue or indirectly blocking the flow of cerebrospinal fluid and causing
- malignant tumours also infiltrate by invading the surrounding region and
destroying cells in its path
- some are sensitive to radiation and can be destroyed by a beam of radiation
focussed on them
o in the brain they remove as much as possible and then target the
remaining cells with radiation
Tumours don’t arise from nerve cells (b/c they can’t divide) so they come other cells in
the brain or from metastasis. For types see TABLE 15.1 PAGE 522
- most serious types are metastases and the gliomas, which are usually very
malignant/fast growing
Glioma: a cancerous brain tumour composed of one of several types of glial cells
- glioblastoma multiformae: poorly differentiated glial cells

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- Astrocytoma: from astrocytes
- ependymoma: from ependymal cells that line the ventricle
- medulloblastoma: from cells in the roof of the fourth ventricle
- oligodendrocytoma: from oligodendrocytes
Meningioma: a benign brain tumour composed of the cells that constitute the meninges
- tend originate in either the part of the dura mater b/t the two cerebral
hemispheres or along the tentorium (the sheet of dura mater b/t the occipital
lobe and cerebellum)
Seizure Disorders
Physicians use the term seizure disorder for epilepsy due to negative connotations
acquired in the past
- second most important category of neurological disorders (after strokes)
- see TABLE 15.2 PAGE 524 for categories
A seizure is a period of sudden, excessive activity of cerebral neurons
- if neurons that make up the motor system are involved it can cause a
o a violent sequence of uncontrolled muscular movements caused by a
o most seizures do not cause these
Two important distinctions in seizure disorders: (1) partial vs. generalized seizures and
(2) simple vs. complex
- Partial seizures: a seizure that begins at a focus and remains localized, not
generalizing to the rest of the brain
o Definite focus or source of irritation (typically a scarred region from
an injury or a developmental abnormality such as a malformed blood
o Neurons involved remained restricted to a small area
- Generalized seizures: a seizure that involves most of the brain, not just a
localized area
o Usually grow from a cous
Partial seizures can be simple or complex
- simple partial seizures: starts from a focus, remains localized, and doesn’t
lose consciousness
o involves changes in consciousness
- complex partial seizures start from a focus, remain localized but produce
loss of consciousness
Grand mal (or tonic-clonic seizures): a generalized seizure which is the most severe and
accompanied by convulsions

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- often before it starts they have warning symptoms like changes in moods or a
few sudden jerks upon awakening
- a few seconds before it occurs the person can experience an aura which is a
sensation whose nature depends on the location of its focus
o effects having to do with what the area the focus does like if the
temporal lobe is where the focus is (which is in control of emotion)
they could suddenly feel angry or euphoric
- tonic phase: the first phase of the grand mal seizure in which all of the
patient’s skeletal muscles contract
o sometimes there is an involuntary scream from muscles around the
lung contracting
o holds a rigid posture for about 15 seconds before entering the next
- clonic phase: the second phase in which the patient shows rhythmic jerking
o literally means “agitated phase”
o muscles are trembling then jerking convulsively, quickly at first then
more and more slowly
o eyes roll, face is contorted with violent grimaces, tongue may be biten
o intense activity of ANS results in sweating and salivation
o after 30 seconds the patients muscles relax and then breathing begins
- after clonic phase they fall into an unresponsive sleep for about 15 minutes
then may awake briefly only to fall back into an exhaustive sleep for a few
Neural activity of a grand mal seizure:
- firing beigns in the focus at the time of the aura then spreads first to around
the focus then to the contralateral side through the corpus callosum
- then to the basal ganglia, the thalamus, and various nuclei of the brain stem
reticular formation
o the symptoms begin here
- the excited subcortical feed back more excitation to the cortex which
amplifies the activity there
- neurons in the motor cortex fire continuously tonic phase
- diencephalic structures try to quench the seizure by sending inhibitory msg to
the cortex
o at first comes in brief burst jerking of the clonic phase (as they
relax and contract again)
o burst of inhibition become more and more prolonged jerking of
clonic phase occurs more slowly
o finally inhibition wins and they completely relax
Partial seizures involve smaller portions of the brain so their symptoms can include
sensory changes, motor activity, or both.
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