531. Which of the following statement regarding axon is FALSE?
A. Progesterone promotes myelin synthesis
B. Wallerian degeneration refers to distal axonal degeneration after transection of axon.
C. Action potential is initiated at the axon hillock
D. Fast anterograde axonal transport is mediated by kinesin
E. Slow anterograde & retrograde axonal transport is mediated by dynesin

532. Depolarizing threshold (threshold potential) of neuron is about:
A. -35mV
B. -4 0mV
C. -45mV
D. -5 0mV
E. -5 5mV

533. Electrotonic potential occur between:
A. -95 to -7 0mV
B. -70 to -5 5mV
C. -55 to DmV
D. 0 to +55mV
E. +55 to +70mV

534. Which of the following statement regarding electrotonic potential is FALSE?
A. Electrotonic potential is due to active opening of NalK channels
B. Electrotonic potential decays exponentially
C. If electrotonic potential reaches depolarizing threshold, action potential will be produced.
D. Decay of electrotonic potential is because the hyperpolarizing force is much stronger than the depolarizing forces.
E. None of the above

535. Which of the following statement regarding nerve conduction is FALSE?
A. Propogation of action potential is unidirectional as the membrane behind the propogational front is in refractory period
B. Saltatory conduction occurs in all types of neurons
C. Strength of stimuli has no correlation with the amplitude of action potential
D. Synapse potentials are not all necessary propogated down the post-synaptic axon
E. All of the above

536. Which of the following statement regarding action potential is TRUE?
A. Generation of action potential is an A TP dependent process
B. Depolarization in the neuron is due to the opening of voltage independent Na channels.
C. Na channels are of high concentration in the regions of nodes of Ranvier.
D. Repolarization of neuron is due to the opening of voltage dependent Ca channels
E. Threshold potential of individual nerve fiber in the peripheral nerve is constant.

537. Which of the following pairing of nerve fiber type & its function is FALSE?
A. Au fiber -somatic motor
B. A8 fiber-Pain, cold & touch sensation
C. Af3 fiber-touch & pressure sensation
D. C fiber -motor to m spindle
E. None of the above

538. Which of the following is TRUE regarding nerve fiber sensitivity to the following situations?
A. Speed of conduction increases with the diameter of nerve fiber.
B. Local anesthetics suppresses smaller diameter nerve fiber before larger diameter ones.
C. Pressure on a mixed nerve causes conduction defects in the larger nerve fibers first.
D. Type B nerve fiber is most susceptible to hypoxia
E. All of the above

539. Which of the following statements regarding sarcomere is TRUE?
A. Thick filament is twice the diameter of thin filament
B. Thick filaments is made up of myosin
C. Thin filaments is made up of actin, tropomyosin & troponin
D. There are no syncytial bridges between individual skeletal muscle cells.
E. All of the above

540. Which of the following statements is FALSE?
A. Sarcoplasmic reticulum is in direct continuum with the extracellular space.
B. Sarcoplasmic reticulum allows rapid transmission of action potential from cell membrane to all myofibril in them
C. Dystrophin is important for structure support & strength of myofibril
D. T tubule system in the skeletal muscle is located at the Z line
E. Calcium is stored in the lateral sacs of sarcoplasmic reticulum.