The brain stem, brain dirsorders LO6, LO7

Question 1

The Brain Stem

Answer 1

midbrain, pons, medulla oblongata and reticular formation

Question 2

Midbrain has white matter
and gray matter

Answer 2

white matter is composed of axon tracts –> conduct
sensory & motor information through the brain stem
gray matter contains nuclei
–> some of these nuclei are associated with the cranial nerves (CN) that arise from the brain stem

Question 3

Midbrain (a.k.a. mesencephalon)

Answer 3

• Gray matter contains various nuclei:
• visual and auditory reflex centres
• substantia nigra –> produces dopamine
• cranial nerve nuclei that regulate eye movements via CN II and CN IV

Question 4

Pons

Answer 4

Gray matter contains:
- cranial nerve nuclei involved in taste, chewing, eye movements, hearing, balance, and facial sensations & expressions via CN V - VIII
- nuclei that regulate breathing

Question 5

Medulla Oblongata

Answer 5

Gray matter contains:
- autonomic nuclei controlled by the hypothalamus
- cardiovascular centre –> controls HR, force of contraction and blood vessel diameter
- respiratory centres –> control the rate and
depth of breathing
- cranial nerve nuclei that regulate swallowing,
tongue movements & digestive functions
via CN IX, X and XII

Question 6

Reticular Formation

Answer 6

(RAS)
- maintains consciousness
- damaged = coma

Question 7

Concussion

Answer 7

Mild brain injury with short-lived effects –> headache,
dizziness, temporary loss of consciousness

Question 8

Contusion

Answer 8

Bruising of the brain
- may cause permanent neurological damage
- may result in a coma

Question 9

Stroke

Answer 9

• blood flow to a brain area is reduced or blocked (ischaemia) and neurons die due due to a lack of oxygen & nutrients (glucose)
  causes:
• blood clot in a cerebral artery = ischaemic stroke
  (most common)
• cerebral blood vessel ruptures and bleeds
  = haemorrhagic stroke
• common symptoms: muscle weakness/paralysis (usually face and arm), loss of vision/blurred vision, difficulty speaking and understanding speech

Question 10

Transient Ischaemic Attack

Answer 10

“Mini stroke”
- blood flow to a brain area is temporarily reduced or
blocked - no neurons die
- symptoms: as per a stroke, but last less than 24 hours
- warning of impending stroke

Question 11

Alzheimer’s Disease

Answer 11

Progressive degenerative disease of the brain
- the death of neurons causes the brain to shrink
- particularly affects hippocampus & prefrontal cortex
- causes ?
- symptoms: memory loss (especially short-term),
confusion and disorientation, personality changes (irritable, moody, paranoid) and an inability to read, write, talk, eat and
walk

Question 12

Parkinson’s Diseas

Answer 12

• Progressive degenerative disease of the brain
• the degeneration and death of dopamine-releasing
  neurons of the substantia nigra = a loss of dopamine
• cause: unknown
• symptoms: minimal facial expression, forward bent
  posture, shuffling gait with no arm swing, difficulty
  speaking and swallowing, and persistent tremors at
  rest