What nerve causes pupillary constriction?

What nerve causes pupillary constriction?

[4] Efferent parasympathetic preganglionic fibers travel on the oculomotor nerve and synapse with the ciliary ganglion, which sends postganglionic axons to directly innervate the iris sphincter muscles. The contraction of the iris sphincter muscles leads to pupillary constriction (miosis).

What cranial nerves affect pupils?

The third cranial nerve is called the oculomotor nerve. It is involved with eye movement, eyelid movement, and the function of the pupil and lens inside the eye.

Which two cranial nerves are involved in the pupillary reaction?

The pupillary light reflex pathway involves the optic nerve and the oculomotor nerve and nuclei.

What nerves are involved in pupillary constriction and accommodation?

Since parasympathetic fibers of the oculomotor nerve mediate ciliary contraction and pupillary constriction, parasympatholytics like atropine results in loss of accommodation and parasympathomimetics like pilocarpine induce accommodation. Vision is not a prerequisite for accommodation reflex.

What part of the brain controls pupil constriction?

The hypothalamus is the control center for many homeostatic mechanisms. It regulates both autonomic function and endocrine function. The roles it plays in the pupillary reflexes demonstrates the importance of this control center.

What part of the brain controls pupil dilation?

hypothalamus
The hypothalamus is the control center for many homeostatic mechanisms. It regulates both autonomic function and endocrine function. The roles it plays in the pupillary reflexes demonstrates the importance of this control center.

What branch of the nervous system controls pupillary response?

parasympathetic nervous system
The parasympathetic nervous system is the main system responsible for pupil constriction in response to light.

Is the pupillary reflex cranial or spinal?

Because most of the cranial nerves are arranged along the brainstem, these reflex arcs are referred to as “brainstem reflexes”. Pupillary light reflex is an example of a brainstem reflex. When light is directed toward eye, CN II (Optic – sensory nerve) will carry the input to CN III.

What does the abducens nerve control?

Cranial nerve six (CN VI), also known as the abducens nerve, is one of the nerves responsible for the extraocular motor functions of the eye, along with the oculomotor nerve (CN III) and the trochlear nerve (CN IV).