Anatomy and Physiology VII

Question 1

What is the function of the direct pathway of the basal ganglia?

Answer 1

To facilitate movement (stimulatory) (p.416)

Question 2

What is the function of the indirect pathway of the basal ganglia?

Answer 2

To inhibit movement (p.416)

Question 3

Which dopaminergic receptors correspond to the direct and indirect pathways respectively?

Answer 3

Direct- D1; Indirect- D2 (p.416)

Question 4

Describe the excitatory pathway through the basal ganglia.

Answer 4

Cortical inputs stimulate the striatum (putamen). This stimulates release of GABA. GABA release disinhibits the thalamus via the Gpi/SNr nuclei. This works to increase motion (p.416)

Question 5

Describe the inhibitory pathway through the basal ganglia.

Answer 5

Cortical inputs stimulate the striatum (putamen). This disinhibits STN via the Gpe nucleus. STN then stimulates the Gpi/SNr nuclei to inhibit the thalamus. This decreases motion (p.416)

Question 6

What is Parkinson’s disease?

Answer 6

A degenerative disorder of the CNS associated with Lewy bodies and loss of dopaminergic neurons (p.416)

Question 7

What are Lewy bodies composed of?

Answer 7

A-synuclein intracellular inclusions (p.416)

Question 8

What changes occur in the substantia nigra pars compacta due to loss of dopaminergic neurons in Parkinson’s disease?

Answer 8

Depigmentation (p.416)

Question 9

What area of the brain is most affected by loss of dopaminergic neurons in Parkinson’s disease?

Answer 9

The substantia nigra pars compacta of the basal ganglia (p.416)

Question 10

Name four clinical features of Parkinson’s Disease.

Answer 10

Resting tremor (“pill rolling tremor”); cogwheel rigidity; Akinesia (or bradykinesia); Postural instability (p.416)

Question 11

What is the inheritance pattern of Huntington’s disease?

Answer 11

Autosominal dominant; trinucleotide repeat of CAG (p.417)

Question 12

What neurotransmitters are decreased in the caudate nucleus of patients with Huntington’s disease?

Answer 12

GABA, Ach (p.417)

Question 13

What are the clinical findings associated with Huntington’s disease?

Answer 13

Chorea, aggression, depression, dementia (p.417)

Question 14

What is the pathophysiology associated with Huntington’s disease?

Answer 14

Neuronal death via NMDA-R binding and glutamate toxicity.

Question 15

What imaging findings can be seen in a patient with Huntington’s?

Answer 15

Atrophy of the striatal nuclei (main inhibitors of movement) (p.417)

Question 16

Name eight disorders of movement.

Answer 16

Hemiballismus; Chorea; Athetosis; Myoclonys; Dystonia; Essential Tremor (postural tremor); Resting tremor; Intention tremor (p.417)

Question 17

What is the characteristic presentation of Hemiballismus?

Answer 17

Sudden, wild flailing of 1 arm +/1 the ipsilateral leg (half of body typically affected) (p.417)

Question 18

What is the characteristic presentation of Chorea?

Answer 18

Sudden, jerky, purposeless movements (dance-like) (p.417)

Question 19

What is the characteristic presentation of Athetosis?

Answer 19

Slow, writhing movements, especially seen in fingers (p.417)

Question 20

What is the characteristic presentation of Myoclonus?

Answer 20

Sudden, brief, uncontrolled muscle contraction (common in metabolic abnormalities) (p.417)

Question 21

What is the characteristic presentation of Dystonia?

Answer 21

Sustained, involuntary muscle contractions (p.417)

Question 22

What is the characteristic presentation of Essential Tremor (postural tremor)?

Answer 22

Action tremor; exascerbated by holding posture/ limb position; genetic predisposition (p.417)

Question 23

What is the characteristic presentation of Resting Tremor?

Answer 23

Uncontrolled movement of distal appendages (most notable in hands) which is alleviated by intentional movement (p.417)

Question 24

What is the characteristic presentation of Intention tremor?

Answer 24

Slow, zigzag motion when pointing/ extending towards a target (p.417)

Question 25

What lesion is characteristically associated with Hemiballismus?

Answer 25

Contralateral subthalamic nucleus (e.g. lacunar stroke) (p.417)