Mod4-Obj6: Brain dysfunction

Question 1

Brain dysfunction

Answer 1

• Traumatic brain injury
• Increased intracranial pressure (ICP)
• Cerebrovascular accidents (CVA, stroke)
• Degenerative brain disorders
• Alzheimer’s disease
• Parkinson’s disease

Question 2

Traumatic brain injury

Answer 2

Head injuries lead to brain damage at the injury site and the opposite side as the brain hits the cranium

Question 3

Concussion

Answer 3

Mild brain injury with short-lived effects

• Temporary alteration in brain function-headache, dizziness, vomiting, irritability, cognitive impairment, loss of consciousness
• Multiple concussions-cumulative damage

Question 4

Contusion

Answer 4

Bruising (haematoma) due to microhaemorrhages

• May lead to increased intracranial pressure (ICP)
• Some degree of permanent neurological damage
• May result in coma

Question 5

Increased intracranial pressure results from…

Answer 5

• Intracranial pressure
• Oedema=swelling due to an accumulation of ISF or CSF
• Tumors, inflammation/infections e.g.) meningitis

Question 6

Increased intracranial pressure: ICF compresses neural tissue…

Answer 6

• Impairs neural function
• May cause tissue damage (via crushing or shifting)
• Interferes with blood flow-ischaemic tissue damage
• May impair CSF circulation-enhances ICP

Question 7

Increased intracranial pressure-Excessive pressure…

Answer 7

• Midline shift-distorts the brain stem

- Herniation of the brain stem (coning)-death

Question 8

Cerebrovascular accidents

Answer 8

‘stroke’-most common nervous system disorder

• Blood flow to a brain area is blocked and tissue dies=Ischaemia
• Tissue damage enhanced by glutamate excitotoxicity
• Most commonly caused by a clot in a cerebral artery (also caused by increased ICP or atherosclerosis)
• Generally leads to one-sided paralysis (hemiplegia) somatosensory deficits, language impairment
• Some function can be recovered-therapy essential

Question 9

Cerebrovascular accidents: Transient ischaemic attacks (TIA)

Answer 9

5-50 minutes

• Temporary numbness, paralysis or impaired speech (precede serious CVA)
• Treatment=dissolved the blood clots

Question 10

Alzheimer’s disease

Answer 10

Progressive degeneration and death of brain tissue=shrinkage of the brain=dementia
-Affects the hippocampus and prefrontal cortex

Question 11

Alzheimer’s disease symptoms

Answer 11

• Memory loss (especially short-term)
• Shortened attention span
• Disorientation
• Language loss
• Irritability
• Confusion
• Dementia

Question 12

Alzheimer’s disease treatment

Answer 12

Drugs that prevent acetylcholine breakdown or block glutamate excitotoxicity

Question 13

Parkinson’s disease

Answer 13

Disease of unknown cause, diagnosed around 50-60 years

• Role for glial cells and inflammation?
• Degeneration of substantia nigra (midbrain)=no dopamine=basal nuclei become overactive=over-dampen motor activity

Question 14

Parkinson’s disease symptoms

Answer 14

Persistent tremors at rest, head-nodding, forward bent posture, shuffling gait, stiff facial expression

Question 15

Parkinson’s disease treatment

Answer 15

L-dopa (converted to dopamine within the brain) alleviates symptoms but does not prevent death of midbrain neurons

Question 16

Summary-Concussion

Answer 16

Mild, traumatic injury with short lived effects

Question 17

Summary-contusion

Answer 17

More serious traumatic injury, some permanent damage

Question 18

Summary-Increased ICP

Answer 18

• Impairs neuron function
• May cause compressive and/or ischaemic tissue damage
• Life threatening

Question 19

Summary-Degenerative diseases

Answer 19

Alzheimer’s disease-Affects prefrontal cortex and hippocampus=cognitive impairment and memory loss (i.e. dementia)
Parkinson’s disease-Lack of dopamine=overactive basal nuclei=excessive dampening of skeletal muscle activity