Brain Damage and Recovery

1. Know the major causes of brain damage and their effects.

Genetic: passed from parent to child through DNA (not necessarily hereditary)

  • e.g., faulty duplication (e.g., Down’s, Turner’s, Klinefelter’s), dominant gene disorders (e.g., Parkisons, Huntington’s), recessive gene disorders (e.g., ALD), and polygenetic disorders (i.e., most psychological and personality traits/disorders).

Congenital: exposure to toxins, drugs, etc., or birth trauma or exposure to STDs.

Environmental: toxins, radiation, drugs, nutrition (e.g., lack of essential amino acids)

  • toxins: alcohol, drugs
  • metal: mercury, lead

Neoplasms: i.e., cancers: invade/steal resources from normal, healthy tissue; can crowd out/put pressure on brain tissue, or damage and kill.

Cell death: either necrosis (externally caused) or apoptosis (normal housekeeping, killing of cells)

Cerebrovascular problems: brain is supplied by 4 major arteries, blockage or bursting of artery can result in damage, death of brain tissue supplied by the blood vessle.

Head impact:

Infections:

2. Know why genetic brain damage is rare.

There are three major types of genetic brain damage:

  • faulty chromosome replication: as in Down’s syndrome, Turner’s or Klinefelter’s
  • dominant gene disorders: are usually self-limiting – person with disorder not likely to reproduce (unless has late onset of symptoms)
  • e.g.: Parkinson’s and Huntingdon’s
  • recessive gene disorders: only 25% of offspring have potential to develop disorder IF both parents carry the gene. These often affect the myelination of cerebral neurons.
  • polygenetic disorders: require several different genetic malfunctions for manifestation of disorder (as well as certain environmental influences).

3. Know the historical and current thinking on why CVAs cause brain death.

CVA: Cerebrovascular Accident:

  • Two main reasons:
  • area of brain previously fed by blood supply is no longer receiving it = death
  • blood builds up pressue on brain
  • Actually due to excess glutamate release from blood-deprived neurons
  • Excess Ca++ and Na influx (through NMDA) receptors
  • Hippocampus is especially affected

4. Know the differences between benign and malignant neoplasms.

Benign neoplasms are not very harmful, they are well-defined and well-contained; they do not intrude into the surrounding tissue.

Malignant neoplasms are very harmful; they are irregularly shaped, and can infiltrate surrounding tissue; can also matasticize and spread to other areas of body; recurrent, kills surrounding tissue.

Neoplasms (general info)

Brain is 2nd to utereus for tumors

typically not from nerves, but from GLIAL cells

Tyrosine  L-DOPA  DA

Cerebrovascular Information

Bi-lateral independent arterial supply both front and back.

Circle of Willis connects all major arteries together, so if one fails, rest can pick up slack.

Mid-cerebral arteries: run along central sulcus

anterior cerebral arteries: run along anterior of brain

posterior cerebral arteries: run along posterior of brain.