Where do endocrine secretions typically act?

Endocrine secretions typically act in various parts of the body after being transported by blood because that's the fundamental characteristic of the endocrine system. Hormones, which are the chemical messengers released by endocrine glands, enter the bloodstream and travel throughout the body to target organs or tissues. This method of transportation allows hormones to exert their effects at distant sites, influencing numerous physiological processes such as growth, metabolism, and mood regulation.

In contrast, the other options suggest more localized or restricted forms of action. For instance, the secretion at the site of secretion would align more with exocrine glands, which release substances directly into specific locations like the digestive tract. Similarly, the notion of action being limited to the digestive tract or the nervous system does not accurately capture the broader systemic nature of hormone action in the body. The ability of hormones to affect multiple organs and systems simultaneously underscores the crucial role of the endocrine system in maintaining homeostasis and coordinating complex biological functions.