Nervous System

Question 1

Name the most abundant CNS neuroglia cell and its function?

Answer 1

Astrocytes Secretion and absorption of neural transmitters and maintenance of the blood–brain barrier

Question 2

Name the defensive cells of CNS and its function?

Answer 2

Microglial cells

Question 3

Which cells line the cerebrospinalfluid-filled cavities? What is the function of these cells?

Answer 3

Ependymal cells Produce cerebrospinal fluid (CSF).

Question 4

Which cells form the myelin sheaths around CNS nerve fibers.

Answer 4

Process of Oligodendrocyte

Question 5

What is the function of Shwann cells?

Answer 5

Forms myelin sheath

Question 6

What is the function of Satellite cells?

Answer 6

Supply nutrients to the surrounding neurons

Question 7

Which cells surround the neurons of the PNS?

Answer 7

Shwann cells and Satellite cells

Question 8

What is the charge close to the cell plasma membrane?

Answer 8

-70millivolts

Question 9

What conditions are required for an action potential generation and propagation?

Answer 9

1) Sodium ion concentrations are higher outside of the cell vs. inside. 2) Potassium ion concentrations are higher inside of the cell vs. outside. 3) Cells are naturally “leaky” with regard to potassium. 4) Cells typically have a slightly negative electrical potential across the cell membrane 5) During Repolarization, the resting membrane potential returns to a negative value due to sodium flowing out at a faster rate than potassium ions flowing in. Hyperpolariation (about -90mV) occurs just before the resting membrane potential of -70 mV is re-established. 6) This process continues along the cell membrane, changing membrane potentials along the cell membrane.

Question 10

What are the stages required for a cell to become polarized?

Answer 10

When the electrical potential of a cell is measured close to the membrane, the inside of the cell is found to be slightly more negative, e.g. about -70 mV (resting membrane potential) b. When an action potential is generated, the cell membrane permeability changes, e.g. sodium ions flow in through voltage-gated channels c. Potassium flows out of the cell at a slower rate than the flow of sodium ions into the cell. d. The membrane potential becomes less negative. If the membrane potential reaches and crosses a threshold of around -55 mV, the cell membrane potential will increase to around +30 mV (the cell is now Depolarized – reversal of polarity)

Question 11

Draw and label the Action potential graph?

Answer 11

see notes