9. Which of the following statements about the regeneration of nerve fibers is incorrect?  a. PNS nerve fibers cannot be regenerated b. CNS nerve fibers cannot be regenerated c. Schwann cells secrete growth inhibiting factors to stop axon regeneration d. Oligodendrocytes secrete growth promoting factors to spur axon regeneration e. none of the above

High blood K+ concentrations cause depolarization of the restingmembrane potential. Predict and explain the effect of high blood K+levels on smooth muscle function

7. Explain how a nerve impulse is conducted from one neuron to another.

1.

4. Draw and label graph showing the changes in membrane potential during a nerve impulse

5. Discuss the steps involved in the generation of a nerve impulse.

54 MS is a disabling disease that disrupts the communication between the brain and the body when the immune system attacks the protective sheaths (myelin) of the axons. Which cells are likely involved in this process? Select one or more: O a. Astrocytes b. Вірolar cells O c. Oligodendrocytes d. Schwann cells O e. Microglia O f. Dendrites O g. Astroglia

3.single choice Which part of the nervous reflex is fatigable. A. synapse B. sensory receptors C. afferent neuron D. efferent neuron E. effector 4.multiple choice The factors that influence the AP conduction velocity on nerve fiber include A. thickness of the myelin shealth. B. myelinated or not C. diameter of the fiber D. temperature E. strength of the stimulation 5.single choice Which property could be destroyed by the local anesthetics procaine (普鲁卡因). A. physiological integrity B. structure integrity C. insulation D. infatigable 6.single choice Which of the following is not the chemical mediated signal transmission. A. gap junction B. neuro-muscular junction. C. hormone binding with the receptor on the target. D. classical synapse E. varicosity 7.single choice In the nerve reflex, the latency from the stimulation to the response is mainly dependent on A. the number of synapses in the central nervous system. B. the action potential…

The walls of blood vessels in the brain are formed by cells that are very tightly packed. This arrangement of cells provides which of the following properties of most brain vasculature?     a. efficient removal of waste products by blood systems     b. rigidity and likelihood of stroke     c. most large and charged molecules cannot move from the blood to the brain     d. easy access to required blood chemicals such as glucose, oxygen, and various hormones   What does it mean to say that acetylcholine exerts ionotropic effects?     a. It opens ion channels.     b. It increases the concentration of ions within the vesicles.     c. It alters the permeability of the presynaptic neuron.     d. It changes the electrical charge of sodium ions from positive to negative.

6. The short period of time when the nerve is not responsive to stimuli it’s termed the: A. Adaptation period B. Accommodation period C. Refractory period D. Resting period