University of Central Florida (UCF) PCB3703C Human Physiology Exam 4 Practice

Norepinephrine is indeed involved in the hyperpolarization of the gastrointestinal (GI) tract. When norepinephrine is released in the context of the sympathetic nervous system response, it interacts with adrenergic receptors in the smooth muscles and gastrointestinal tissues. This interaction can lead to a decrease in the excitability of the neurons and cells in the GI tract, thus resulting in hyperpolarization.

Hyperpolarization refers to an increase in the membrane potential, making it more negative and moving it further away from the threshold needed to trigger an action potential. This inhibitory effect slows down GI motility and reduces digestive activity, aligning with the body's need to conserve energy and resources during stress or 'fight or flight' situations.

Understanding this process is essential for recognizing how neurotransmitters modulate physiological functions and how balance between sympathetic and parasympathetic activity is crucial for maintaining digestive health.