Which branch of the autonomic nervous system regulates constricting of the pupil? Which dilates the pupil?

1.        Which cranial nerve is involved in the afferent portion of the pupillary reflex (pupil constricting)?

 The efferent limb of the pupillary reflex relays its enervation onto the ciliary ganglia via which cranial nerve?

1.        Optic nerve synapses on pre-tectum then short bilateral projection to both accessory occulomotor nuclei or Edinger westphal nuclei then axons project out to ciliary ganglion via cranial nerve III, these projections enervate smooth muscle controlling pupil diameter.

1.        Where do the Preganglionic motor neurons in this parasympathetic pathway live? Where do the post ganglionic motor neurons in this parasympathetic pathway live?

1.        The Accessory Occulomotor motor nucleus houses the preganglionic neurons, the Ciliary ganglion is the ganglion (for parasympathetic ANS the ganglion live on or near their targets) in which the projections are considered “post ganglionic” and they enervate the target muscle, in this case the smooth muscle of the pupillary sphincter.

True or False: the pretectum provides bilateral innervation to both accessory oculomotor nuclei, constricting both pupils if light shines into only one eye.

 This reflex uses fast conducting axons which mean the axons involved are what?

What does it mean when “pupils are fixed and dilated”?

1.  Bad news, if the person is unconscious than definite mid brain damage, where the accessory oculomotor nucleus is because that’s the preganglionic nuclei responsible for constricting the pupils and they’re dilated…

If shining a light into an affected eye produces a consensual constriction of the pupil in the opposite eye, but not in the direct eye, what is this evidence of? Hint: Where is the lesion? Use afferent and efferent terminology

 lesion present in efferent pathway of reflex in ipsilateral oculomotor nerve

      Explain what symptoms are present in an optic nerve lesion, and how can this be clinically determined?

 can’t see out of affected eye, can be determined clinically after shining a light onto the affected eye producing no response then shining light into non affected eye causing consensual constriction of pupils. (both eyes constrict)

  Explain nasal and temporal visual fields.

1.        Nasal receives light from the left side of the eye and temporal receives light from the right side of the eye, adding the two produces a large visual field

 Information from one retina crosses to the contralateral side at the optic chiasm, which portion of the retina projects to the contralateral side of the brain? Which portion remains ipsilateral?

Nasal crosses, temporal ipsilateral

    True or False: 90% of the optic nerve projections synapse onto layers in the LGN (Lateral Geniculate Nucleus)

 True.

After the crossing at the optic chiasm, if the information traveling down the optic tract is perceived as visual information instead of a reflex or used for orienting the head, the information projects to what portion of the Thalamus?

  Lateral Geniculate Nucleus

   Retina to LGN to VI

    True or false: x and p are names given to the same populations of ganglion neurons

True or false: y and m are names given to the same populations of ganglion neurons