Which of the following are basic control mechanisms of the GI tract?

The basic control mechanisms of the gastrointestinal (GI) tract are indeed comprised of the autonomic nervous system (ANS), hormonal control, and chemical control. Each of these mechanisms plays a crucial role in regulating various aspects of GI function, including motility, secretion, and blood flow.

The ANS, which includes both the sympathetic and parasympathetic systems, provides rapid responses to changes in the internal environment or external stimuli, coordinating activities such as digestion and absorption. Hormonal control involves various hormones, such as gastrin, secretin, and cholecystokinin, which are released into the bloodstream and influence GI processes like enzyme secretion and gut motility. Chemical control pertains to the actions of neurotransmitters and other biochemical factors that directly influence smooth muscle contractions and secretory activities in the gut.

Combining these control mechanisms ensures that the GI tract functions efficiently in response to the needs of the body, adapting to different states such as rest or the presence of food. In contrast, the other options suggest an exclusive reliance on only one aspect of these control mechanisms, which does not accurately reflect the complexity and integration necessary for proper GI function.