Test 64 (physiology)
1. In the skeletal muscle:
a. myosin is found in the thick filament

b. the thin filament contains actin and troponin

c. during stimulus excitation calcium ions are derived from 
    the serum

d. tropomyosin masks the myosin-combining sites on the 

e. the resting membrane potential is about -90 mV

2. The conduction velocity of the nerve fibres is increased by:

a. decreased temperature

b. increased concentration of the external sodium ions

e. increased axon diameter

d. myelination

e. increased serum calcium ions

3. In the neurone:

a. the magnitude of the action potential is dependent on the strength of the stimulus

b. impulses can travel in both direction

c. depolarization is accompanied by increased permeability of the cell membrane to potassium ions

d. during depolarization, the potential of the neurone changes from -70mV to +40mV

e. the refractory period of the nerve is dependent on the refractory period

4. The following are true about the neurotransmitters:

a. acetylcholine is inactivated mainly by presynaptic 

b. tyrosine is essential for the formation of dopamine

c. noradrenaline is inactivated mainly by hydrolysis

d. adrenaline is formed from methylation of the 

e. serotonin is synthesized from trytophan.

5. The muscle spindles:

a. are extrafusal fibres

b. are innervated by type Ia and II fibres

c. received motor innervation from the gamma fibres.

d. respond to tension in the muscle

e. respond to rate of change in the length of the muscle

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