Which of the following statements concerning gap junctions is incorrect?
a. gap junctions are communicating junctions.
b. at a gap junction, filaments of unknown composition extend between the plasma membranes of two closely adjacent but not touching cells, acting as "spot rivets" to anchor the cells together.
c. gap junctions are formed by small connecting tunnels that link two adjacent cells and permit exchange of small water-soluble particles between the cells.
d. gap junctions play an important role in transmission of electrical activity throughout an entire muscle mass.
e. connexons are an important structural component of gap junctions.
B
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The area between Z lines is the
A) sarcolemma. B) sarcomere. C) sarcoplasmic reticulum. D) myofibril. E) myofilament.
Which statement is FALSE?
A. If the receptive field is small, precise localization of the stimulus is easily determined. B. The receptors in our ears for balance and equilibrium are tonic receptors. C. The special senses are examples of interoceptors. D. The interoceptors, or visceroceptors, are primarily stretch receptors. E. Pacinian corpuscles, Meissner corpuscles, Krause bulbs. and Ruffini corpuscles are examples of encapsulated receptors.
A patient is admitted to the hospital in complete collapse. His blood pH is 6.8, and his HCO3- is 20 mEq/L. What diagnosis would you give and what prognosis? A medical history reveals that this patient is a chronic alcoholic.
What will be an ideal response?
The feet of the sensory homunculus are located
A. medially on the postcentral gyrus. B. medially on the precentral gyrus. C. laterally on the postcentral gyrus. D. laterally on the precentral gyrus.