Which of the following situations occurs in electrically excitable cells?
A. When Na+ ion channels open, K+ ion channels close.
B. The sodium-potassium exchange pump moves sodium into the cell.
C. Depolarization causes voltage-gated sodium ion channels to open.
D. Ligand-gated sodium ion channels are opened by high extracellular calcium levels.
E. Proteins tend to diffuse out of the cell.
C
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The ________ gland is located deep between the cerebral hemispheres attached to the roof of the third ventricle.
Fill in the blank(s) with the appropriate word(s).
List three ways that neural reflex pathways can be classified. Name one of the reflexes in each category. What additional information may be gained from the name of the reflex? Name a specific reflex and identify its classification in all of the categories you listed.
What will be an ideal response?
The complex processing and integration of neural information from peripheral structures, visceral information from the eyes, and equilibrium-related sensations from the inner ear are performed by the ________.
Fill in the blank(s) with the appropriate word(s).
Which of the following statements about the refractory period of a membrane is TRUE?
A. The absolute refractory period refers to the period of time during which another action potential cannot be initiated in that part of the membrane that is undergoing an action potential, no matter how great the strength of the stimulus. B. The relative refractory period refers to the period of time during which another action potential can be initiated in that part of the membrane that has just undergone an action potential if a stronger than normal stimulus is applied. C. The refractory period prevents the action potential from spreading back over the part of the membrane that just underwent an action potential. D. The refractory period places an upper limit on the frequency with which a nerve cell can conduct action potentials. E. All of the above choices are correct.