When Responding to Stimulation of the Outer Margin of the Sole

question 125

Multiple Choice

When responding to stimulation of the outer margin of the sole of the foot,a 1-year-old infant extends her great toe without fanning of the other toes.This happens because:

• A) the corticospinal fibers have become fully myelinated and the Babinski reflex becomes suppressed.
• B) the corticospinal fibers have not yet become fully myelinated and the Babinski reflex is activated.
• C) the sensory fibers in the ophthalmic branch of the fifth cranial nerve are mediated by reflex arcs.
• D) a deep reflex is mediated by a two-neuron spinal arc.

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Definitions:

Hormones

Hormones are chemical messengers produced by the endocrine system that regulate various physiological processes and behaviors in the body.

Endocrine Glands

Glands of the endocrine system that release hormones directly into the blood to regulate body functions.

Synaptic Vesicles

Small sac-like structures in neurons that store neurotransmitters, which are chemicals responsible for transmitting messages across synapses.

Thyroid

A gland located in the neck region that produces hormones regulating growth, development, metabolism, and body temperature.