ic2 and 3 (physio)

Question 1

Afferent nerves

Efferent nerves

Answer 1

Towards CNS

Away from CNS

Question 2

Examples of noxious stimuli

Answer 2

Mechanical

Thermal (temperature)

Chemical (eg. capsaicin)

Question 3

What happens during upstroke?

What happens during downstroke?

Answer 3

Upstroke: Na+ channels activated, Na+ enters cell

Downstroke: Na+ channels deactivated, K+ channels activated, K+ leaves the cell

Question 4

Damage to Broca’s area and Wenicke’s area

Answer 4

Damage leads to difficulty in expressing language, difficulty comprehending language

Question 5

Subgenual Anterior Cingulate Cortex (ACC)

Answer 5

Higher activity of Subgenual ACC → more Depression

Question 6

Hippocampus

Answer 6

Involved in declarative memory eg. events, names
Lesion in Hippocampus leads to Alzheimer’s disease

Question 7

Amygdala

Answer 7

Emotions, recognise facial expression

Question 8

What is a modality

Answer 8

a class of stimuli eg. vision

Question 9

Where does the touch pathway travel along

Answer 9

Dorsal column pathway

1st order neuron travels up the Dorsal column, synapse and crosses over at the Medulla

Question 10

Where does the pain pathway travel along

Answer 10

Spinothalamic tract pathway

1st order neuron synapse at the dorsal horn, 2nd order neuron crosses over in the Spinal Cord, travels from Spinal Cord to Medulla and Thalamus

Question 11

where does touch pathway and pain pathway crossover occur?

Answer 11

touch: cross at medulla
pain: cross at spinal cord

always synapse then cross

Question 12

What is a labelled line

Answer 12

the receptor and its associated first order neurons

Question 13

What is topographic line

Answer 13

orderly mapping of entire body

Different somatic surfaces (body parts) will give rise to different topographic relays

Question 14

Which part of body corresponds to which part of cortex

Answer 14

Upper body parts (eg. eyes, face, tongue) will be more lateral (outer part of brain)

Lower body parts (eg. trunk, hip, leg) will be more medial (middle part of brain)

Question 15

How does touch allodynia occur?

Answer 15

1. Inhibitory neuron damaged
2. Hyperexcitability
   Tissue damage lead to release of chemicals eg. Prostaglandin, Serotonin, Bradykinin

Mediators will increase TRV1 receptors on the 2nd order neuron (spinothalamic tract neuron) or decrease threshold to excite TRV1 receptor

1st order neuron synapses on the spine of 2nd order neuron (Spinothalamic tract neuron), releasing more Glutamate

Hyperexcitability causes 1) more AMPAR receptors on the spine, 2) Lower threshold to excite AMPAR receptors

Since spinothalamic tract neuron becomes more hyperexcitable (more AMPAR receptors, lower threshold to excite AMPAR receptors), it amplifies the
excitatory inputs from C fiber → Hyperalgesia
+ Weakly excitatory input from A-Beta fibre (which overrides inhibitory nerve) → Touch allodynia

Question 16

How is pain modulated?

Answer 16

Morphine acts on Periaqueductal gray in midbrain, signal travel down nucleus raphe magnus, inhibitory neuron releases Enkephalin to inhibit signal from C fibre to spinothalamic tract

Question 17

3 types of movement

where are they generated?

Answer 17

Reflex, Rhythmic, Voluntary

Reflex Rhythmic -> Brainstem
Voluntary -> cortex

Question 18

2 pathways controlling efferent

Which one is contralateral

Where does synapse occur?

Answer 18

Corticospinal pathway
Brainstem pathway

Corticospinal pathway

Ventral horn

Question 19

Function of basal ganglia

What disease is caused by damage of basal ganglia

Answer 19

Affects initiation of movements

Parkinsons disease