In paracrine communication a chemical signal acts within the tissue that produced it; in endocrine communication the signal reaches the target cells by way of the circulation. Are these two statements true or false?

True

Explanation:

Paracrine communication occurs when a local hormone or a chemical released by particular cells act on the neighboring cells. These hormones/chemicals are not released into the bloodstream.

For example, nitric oxide gas is released by endothelial cells present in the lining of the blood vessels. The gas relaxes the smooth muscle fibers present nearby in the lining.

Endocrine communication occurs when the hormones from the endocrine glands are released into the bloodstream. These hormones reach the target cells/tissue along with blood circulation.

For example, thyroxine hormone is released in the blood from the thyroid gland and targets all the body cells to increase the basic metabolic rate.