illustrate the neuronal pathway that causes pupillary constriction. 6) Using the
ID: 3518866 • Letter: I
Question
illustrate the neuronal pathway that causes pupillary constriction.
6) Using the attached "Diagram B" illustrate the neuronal pathway that causes pupillary dilation -Using the attached "Diagram C" illustrate the neuronal pathway that causes pupillary constriction. Then in a short paragraph explain your illustration making sure to include wher the cell bodies for the preganglionic and postganglionic neurons are located, the structure of the axons, where the neurons synapse (name of autonomic ganglion), the neurotransmitters used and the effector. (20-points)Explanation / Answer
In response to light intensity , the diameter of pupil changes ( in bright light pupil constrict so as to allow less light)
NEURONAL PATHWAY=
AFFERENT IS cranial nerve 2
EFFERENT IS cranial nerve 3
** afferent limb starts with ganglionic cells projecting through OPTIC NERVE ( 2ND cranial nerve) to pretectal nucleus in mid brain.
From pretectal nucleus , fibres are projected to ipsilateral and contralateral EDINGER - WESTPHAL NUCLEUS in midbrain.
Effernt= from this nucleus preganglionic parasympathetic fibres originate and exit via 3rd cranial nerve and goes to ciliary ganglion.
From where post ganglionic fibres leave to innervate ciliary mucles of iris which helps in controlling the diameter of pupil.
Each neuronal pathway consists of one afferent and two efferent( one to same side for direct pupillary reflex , another to opposite side for consensual pupillary reflux)
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