Test 54   (neural physiology)

1. The following are true about pain:

a. in disseminated cancer can be effectively relieved by 
    hypophysectomy

b. does not ascend through the dorsal column of the spinal 
    cord

c. is transmitted faster through the C fibres than the A 
    delta fibres

d. stimulation of the ß receptors in the brain produces 
    analgesia

e. injection of 100% alcohol into the retrobulbar space is 
    useful in treating intractable ocular pain

Answera.T   b.F   c.F  d.T   e.T
Although the spinothalamic and spinoreticular tracts conduct most of the pain sensation; some pain travels up the dorsal column.
Pain travels faster through the A delta fibres.
Stimulation of the beta receptors produces analgesia and is common with opiates.

2. The following are true about the spinal cord:

a. segment T12 lies at the level of vertebral body T9

b. cerebrospinal fluid is found within the subdural space

c. two point discrimination is transmitted in the dorsal 
    column

d. hemisection results in contralateral loss of pain and 
    temperature sense below the lesion.

e. hemisection results in contralateral upper motor neuron 
    paralysis below the level of the lesion.

Answera.T   b.F   c.T   d.T   e.F
Cerebrospinal fluid is found in the subarachnoid space.
Hemisection of the spinal cord results in ipsilateral upper motor neuron paralysis.

3. Stimulation of the cholinergic pathway results in:

a. ciliary muscle contraction

b. a decrease in atrial contractility

c. gall bladder contraction

d. ejaculation

e. contraction of the detrusor muscle

Answera. T   b.T   c.T   d.F   e.T
Cholinergic stimulation leads to erection.
 

4. The following drugs are miotics:

a. carbachol

b. cocaine

c. scopolamine

d. isofluorosphosphate

e. salbutamol

Answera.T   b.F   c.F   d.T   e.F
Carbachol is a parasympathomemitic drug and isofluorosphosphate a cholinesterase inhibitor.
Cocaine and salbutamol are sympathomemitic and scopolamine parasympatholytic drugs.

5. The following are true about the synaptic potential:

a. the Na⁺ and K⁺ currents occurs simultaneously

b. is a graded potential

c. the channel is ligand-gated

d. the post-synaptic potential is inhibitory when 
    depolarizing

e. the post-synaptic potential is inhibitory when GABA 
   binds to post-synaptic receptors.

Answera.T   b.T   c.T   d.F   e.T
The postsynaptic potential is excitatory when depolarizing.