Human Physiology

Only available on StudyMode
  • Download(s) : 1354
  • Published : May 31, 2009
Open Document
Text Preview
Neurophysiology of Nerve Impulses


1. Match each of the definitions in Column A with the appropriate term in Column B. Column A
Column B
__D__ term that refers to a membrane potential of about -70 mv __F__ reversal of membrane potential due to influx of sodium ions __B__ major cation found outside of a cell
__A__ minimal stimulus needed to elicit an action potential
__E__ period when cell membrane is totally insensitive to additional stimuli, regardless of the stimulus force applied __C__ major cation found inside of a cell
a. threshold
b. sodium
c. potassium
d. resting membrane
e. absolute refractory period
f. depolarization

2. Fill in the blanks with the correct words or terms.
Neurons, as with other excitable cells of the body, have two major physiological properties: _irritability____ and _conductivity___. A neuron has a positive charge on the outer surface of the cell membrane due in part to the action of an active transport system called the __sodium-potassium pump______. This system moves _sodium____ out of the cell and ___potassium___ into the cell. The inside of the cell membrane is negative, not only due to the active transport system but also because of _intracellular proteins_, which remain negative due to intracellular pH and keep the inside of the cell membrane negative.

3. Why don’t the terms depolarization and action potential mean the same thing? -Depolarization and action potential did not mean the same thing because are excitable cells that communicate by transmitting electrical impulses that are capable of producing rapid electrical signals and depolarization in the interior surface of the membrane which becomes less negative and the exterior surface becomes less positive. When depolarization reaches a certain threshold, an action potential is initiated and the polarity of the membrane reverses.

4. What is the difference between membrane irritability and membrane conductivity?...
tracking img