The Amount of Light Reaching the Retinas Is Controlled by Two

question 58

Multiple Choice

The amount of light reaching the retinas is controlled by two donut-shaped bands of contractile tissue called the

• A) pupils.
• B) scleras.
• C) corneas.
• D) foveas.
• E) none of the above

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Definitions:

Nasopharynx

Part of the pharynx that lies above the soft palate; anteriorly it opens into the nasal cavity.

Cuboidal Epithelium

A type of epithelial tissue with cube-shaped cells, often found lining glands and ducts, involved in secretion and absorption.

Acetylcholine

A neurotransmitter that plays a role in muscle movement and various brain functions.

Norepinephrine

Neurotransmitter substance released from most of the postganglionic neurons of the sympathetic division; hormone released from the adrenal cortex that increases cardiac output and blood glucose levels; also called noradrenaline.