The mechanism by which atropine causes pupillary dilation and its implications on the role of the autonomic nervous system (ANS) in controlling pupil diameter. Introduction: The size of the pupil is controlled by the constrictor muscles and dilator muscles surrounding the pupil. Cataract is a condition in which the lens of the eye becomes nontransparent and hazy due to UV (ultraviolet) light exposure and aging. The cataract is removed by a complex surgery, which requires the pupil to be dilated for a long period of time. Pupillary dilation has been achieved by using epinephrine and norepinephrine.

Question

Want to see the full answer?

Answer 1

Question

Chapter 40, Problem 4Q

Summary Introduction

To review:

The mechanism by which atropine causes pupillary dilation and its implications on the role of the autonomic nervous system (ANS) in controlling pupil diameter.

Introduction:

The size of the pupil is controlled by the constrictor muscles and dilator muscles surrounding the pupil. Cataract is a condition in which the lens of the eye becomes nontransparent and hazy due to UV (ultraviolet) light exposure and aging. The cataract is removed by a complex surgery, which requires the pupil to be dilated for a long period of time. Pupillary dilation has been achieved by using epinephrine and norepinephrine.

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Students have asked these similar questions

What effect does sympathetic nervous system stimulation have on pupil diameter? It is known that one's diameter of the pupil's increases when telling a lie. Offer an explanation.

What aspect of the neural circuity in the pupillary light reflex is responsible for the consensual response? a. Preganglionic parasympathetic neurons project their axons to neurons in the ciliary ganglion. b.Pretectum neurons send axons to the Edinger-Westfall nuclei on both sides of the brain. c. Neurons in the ciliary ganglion innervate the constrictor muscle in the iris, which decreases the diameter of the pupil when activated. d. The muscles in the iris encircle the pupillary opening so that light enters in the center of the eye. e. The ciliary muscles contract concentrically to release the tension in the zonule fibers.

Which of the following statements about the eye is/are TRUE? Group of answer choices Parasympathetic (sympathetic) innervation of the sphincter pupillae stimulates pupil dilation. Photoreceptors in the retina are of two types: rods and cones. Eye color is determined by that of the iris. A. Light striking the fovea centralis goes unnoticed and is commonly called the "blind spot". B. Light entering the eye passes through the cornea, anterior chamber, pupil, lens, and vitreous body, from outer to inner.(posterior only) C. Movement of the extrinsic muscles of the eye is controlled by the autonomic (optic nerve) nervous system. D. Because lacrimal fluid ultimately enters into the nasal cavity, people often sniffle when they cry. F. The adjustability of the lens allows the eye to focus on nearby objects.