Refractory/Propag Dr. Jones Neuro Exam 1

Which of the following is due to to inactivated Na+ channels and NO STIMULUS?

• Absolute refractory period

• Relative refractory period

Which of the following causes NO stimulus of any strength will lead to a new action potential?

• continue outward diffusion of K+

• inactivated Na+ channels

• continue inward diffusion of K+

• activated Na+ channels

Which of the following may elicit an action potential with a stronger stimulus in the Relative refractory period?

• inactivated Na+ channels

• continued outward diffusion of K+

• activated Na+ channels

• continued inward diffusion of K+

How can the number of action potentials can be increased?

• decreasing the strength in stimulus

• increasing the strength in stimulus

• inhibiting the strength in stimulus

• stopping the strength in stimulus

In which region the action potentials are initiated where we reach the threshold of depolarization in the initial segment?

• dendrites

• axon hillock

• nucleus

• soma

Where does the slow continuous conduction occur?

• unmyelinated axons

• myelinated axons

• unmyelinated dendrites

• myelinated dendrites

• cell body

Which of the following statements is TRUE about fast Saltatory Conduction?

• unmyelinated axons increases conduction velocity

• it takes more time due to the unmyelinated axons

• myelination and larger diameter axon increases conduction velocity

• myelination decreases conduction velocity

• myelination and smaller diameter axon increases conduction velocity

A 16 years old patient shows to the emergency department due to having fatigue, dysphagia and ataxia. The patient has a clinical history of Multiple Sclerosis diagnosed two years ago. This autoimmune disease affects the brain and spinal cord in the CNS.

Which of the following is occurring in this patient within this autoimmune disease?

• increased conduction velocity due to Oligodendrocytes produced by myelin being attacked

• decreased conduction velocity due to Oligodendrocytes produced by myelin being attacked

• decreased conduction velocity due to Schwann cells produced by myelin being attacked

• increased conduction velocity due to Astrocytes produced by myelin being attacked