As the eyes rotate upward, the upper eyelid reflexively retracts. Which cranial nerve is primarily responsible for this response?
A)
Cranial nerve I
B)
Cranial nerve III
C)
Cranial nerve VI
D)
Cranial nerve IV
Ans:
B
Feedback:
The CN III (oculomotor) nucleus, which extends through a considerable part of the midbrain, contains clusters of lower motor neurons for each of the five eye muscles it innervates. Because of its plane of attachment, the inferior oblique rotates the eye in the frontal plane pulling the top of the eye laterally. In other words, as the eyes rotate upward, the upper eyelid is reflexively retracted, and in the downward gaze, it is lowered, restricting exposure of the conjunctiva to air and reducing the effects of drying. CN I is involved in olfactory function; CN VI (abducens nerve) innervates the lateral rectus, which abducts the eye. CN IV (trochlear nerve) innervates the superior oblique muscle, which depresses, rotates laterally, and intorts the eyeball.
You might also like to view...
Oliguria in an eclamptic patient is an indication of
A) dehydration. B) hypovolemia. C) decreased glomerular filtration rate. D) All of the above are correct.
The 42-year-old client with presbyopia asks her nurse how corrective lenses will help her problem. What is the nurse's best response?
A. "This type of problem cannot be helped with corrective lenses." B. "The correct lenses will be needed for both near and distance vision." C. "The corrective lenses will need to be used for reading and close work only." D. "The corrective lenses will not change your near vision and will be needed for distance only."
A drop is always the most reliably accurate of all forms of measurement
Indicate whether the statement is true or false
The PACU nurse administers Narcan, an opioid antagonist, to a post op client. Which client problem should the nurse include to the plan of care based on this medication?
1. Alteration in comfort 2. Risk for depressed respiratory pattern 3. Potential for infection 4. Fluid and electrolyte imbalance