Neuroanatomy

Question 1

What is the role of astrocytes? (3)

Answer 1

Support, maintain the BBB and environmental homeostasis.

Question 2

Why do we have gyri and sulci in the structure of the brain?

Answer 2

To allow a greater SA for grey matter; this is where we do most of our thinking.

Question 3

At which vertebral level does the spinal cord terminate and what structure does it form?

Answer 3

L1/L2; conus medullaris from which the caudal equina extend.

Question 4

There are 3 major longitudinal spinal arteries; what is there distribution between anterior and posterior sides and from where do they originate?

Answer 4

1 anterior, 2 posterior; all 3 originate from the vertebral arteries.

Question 5

Roughly describe the somatotopic organisation of the somatosensory gyrus?

Answer 5

Medially starting off with the genitals progressing to the foot and leg.
Then, moving laterally along the gyrus we move towards the arm and progress to the hands and lips, for which there is a much greater representation.

See homunculus.

Question 6

What sensations is the dorsal column responsible?

Answer 6

Fine touch, vibration and conscious proprioception.

Question 7

What sensations is the spinothalamic tract responsible for?

Answer 7

Pain, temperature and crude touch.

Question 8

Roughly describe the somatotopic organisation of the somatomotor cortex?

Answer 8

Medially starting off with the toes and foot, progressing laterally onto the leg and shoulder.
Moving further laterally we move onto the arm before reaching the hand, face, lips, vocalisation, salivation and mastication.
The hand is represented more than in the somatosensory cortex, as with the muscles of mastication and vocalisation.

See homunculus.

Question 9

What is the corticospinal tract responsible for?

Answer 9

Fine, precise movement.

Question 10

What is thought of as the “movement computer” of the brain? Name 2 other functions this structure possesses

Answer 10

Cerebellum; memory and muscle memory

Question 11

Why does acute alcohol exposure result in a staggered gait and slurred speech?

Answer 11

Bilateral cerebellar dysfunction can occur after acute alcohol exposure; resulting in dysarthria, with bilateral incoordination of the arms and cerebellar ataxia.

Question 12

A midline lesion of the cerebellum will have an affect on which modality?

Answer 12

Postural control; patient will tend to fall over when standing or sitting, despite preserved limb coordination.

Question 13

What are the 3 functions of the basal ganglia and where are they located?

Answer 13

1) Facilitate purposeful movement
2) Inhibit unwanted movements
3) Roles in posture and muscle tone

Located near the base of each cerebellar hemisphere.

Question 14

Which particular structure in the basal ganglia has implications in PD?

Answer 14

Substantia nigra

Question 15

For unilateral lesions in the following structures, state whether the contralateral/ipsilateral side is affected:

1) Somatosensory cortex
2) Cerebellum
3) Basal ganglia

Answer 15

1) Contralateral
2) Ipsilateral
3) Contralateral

Question 16

Why, in a CNVII palsy, can the upper face be spared?

Answer 16

Because this portion has a bilateral motor supply, unlike the lower half of the face.

Question 17

Damage in Broca’s area has what affect on language?

Answer 17

Difficulty producing language; patient may appear frustrated.

Question 18

Damage in Wernicke’s area has what affect on language?

Answer 18

Difficulty comprehending language; patient may have meaningless responses to questions.