Structure and Function of Organs and Organ Systems
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The intrinsic rate of the pacemaker cells in the AV node is:
slower than the rate in the SA node
faster than the rate in the SA node
equal to the rate in the SA node
varies (sometimes faster, sometimes slower than the rate in the SA node)
the AV node does not contain pacemaker cells
Explanation
The intrinsic rate of depolarization is slower among the pacemaker cells in the AV node compared to the rate in the SA node.
Activation of the sympathetic nervous system will cause which of the following to occur?
Dilation of the pupil
Constriction of the pupil
Increase in intraocular pressure
A rounding of the lens
A flattening of the lens
Explanation
Activation of the sympathetic nervous system will cause dilation of the pupil. Activation of the parasympathetic nervous system will cause constriction of the pupil.