The plasma membrane of an excitable cell is more permeable to K+ because
A. there are more leak ion channels for K+ than Na+.
B. protein molecules cannot exit through the plasma membrane.
C. there are more gated channels for K+.
D. of its positive electrical charge.
E. calcium ions block Na+ and Cl- channels.
Answer: A
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Which is TRUE about the resting membrane potential?
A. Only nerve and muscle cells have a potential difference across the membrane at rest. B. It requires very few ions to be distributed unevenly. C. It is oriented so that the cell's interior is positive with respect to the extracellular fluid. D. It has the same value in all cells. E. It is not altered by changing concentration gradients of permeating ions.
Which brain structure is responsible for the "startle reflex" in response to loud sounds?
a) Superior colliculus b) Inferior colliculus c) Pontine nucleus d) Medial lemniscus e) Arbor vitae
Using Figure 10.3, match the following:
1) Trapezius muscle.
2) Teres major muscle.
3) The latissimus dorsi.
4) Rotates scapula.
5) Retract scapula.
6) Levator scapulae.
Muscles of the vertebral column extend, flex and rotate the vertebral column.
a. True b. False