All cells do not respond to endocrine system stimulation. Only those that had proper_________on their cell membranes are activated by the chemical messengers.
These responsive cells are called the _____ ____ of the various endocrine glands.
Hormones promote homeostasis by _______ _________ of the body cells, rather than by _______ ___ __ _______ ________.
Altering activity, stimulating new or unusual activity
Most hormones are ______ or ____ ___ molecules
steroid, amino acid
The various endocrine glands are prodded to release their hormones by nerve fibers (a ______ stimulus), or by the presence of increased or decreased levels of various other substances in the blood ( a ______ stimulus).
The secretion of most hormones is regulated by a ________ ______ system, which increasing levels of that particular hormone "turns off" its stimulus.
The _____ _______ is called the master endocrine gland because it regulates so many other endocrine organs.
However, it is in turn controlled by _______ ________ secreted by the _______.
releasing hormones, Hypothalamus
This structure is also part of the brain, so it is appropriately called a __________ organ.