2. Schwann cells are a type of glial cell found in the nervous system. In addition to the conduction of nerve impulses, the outermost layer called neurilemma aids in nerve development and regeneration.
After examining the image below, can you explain why brain cells have limited capacity for regeneration?
Cross Section of Human Brain
Human Brain Cross Section. Rajalakshmi L Nair et al.
Select one:
a. Neurons in the central nervous system lack neurilemma of Schwann cells.
b. Neurons in the central nervous system are surrounded by white matter.
c. Neurons in the peripheral nervous system are surrounded by grey matter.
d. Axons of the peripheral nervous system lack neurilemma of Schwann cells.
8.
Match each structure in the reflex arc numbered above with its description given below.
Structure: Answer Answer Answer Answer
Description:
Dendrite of a
motor neuron
Axon terminal of
a motor neuron
Dendrite of a
sensory neuron
Axon terminal of
a sensory neuron
22. Both potassium and sodium channels located along the nerve membrane are voltage-gated. This means that they respond to the changes in the voltage by opening and closing the gates to allow the ions to flow in or out of the membrane.
When the threshold level is reached and depolarization occurs, how come only the sodium ions begin to rush in?
Select one:
a. The threshold level for the potassium channels is lower than the sodium channels.
b. The threshold levels for both sodium and potassium channels are equal, but sodium channels are slower to open.
c. The threshold level for the potassium channels is higher than the sodium channels.
d. The threshold levels for both sodium and potassium channels are equal, but potassium channels take longer to open.
23.During an action potential, the inside of the cell membrane becomes more positive than the outside. Why does this happen?
Select one:
a. During depolarization, the sodium ions rush in and the potassium ions have not begun rushing out, making the outside more positive.
b. During depolarization, the sodium ions rush in and the potassium ions have begun rushing out, making the outside more positive.
c. During depolarization, the potassium ions rush in and the sodium ions have begun rushing out, making the inside more positive.
d. During depolarization, the sodium ions rush in and the potassium ions have not begun rushing out, making the inside more positive.