The International Union for the Conservation of Nature (IUCN) lists 9 species of spider monkey, which can be found in rain forests from southern Mexico through Brazil. The IUCN lists 3 spider-monkey species as Critically Endangered; 5 species of spider monkey are listed as Endangered, and 1 species is Vulnerable.
The foundations of the endocrine system are hormones and glands. A gland is a group of cells that produces and secretes hormones. Hormones are the body's chemical messengers. They send and relay messages between different systems. Many different hormones move through the bloodstream.
The main body systems involved in hormone regulation by feedback mechanisms are: 1  the nervous system. ... 2  signals input to and output from the control centre are either. 3  which are part of the. , 4  or chemical signals. 5  the endocrine system.... 6  which produces and secretes hormones.he main body systems involved in hormone regulation by feedback mechanisms are: 1  the nervous system. ... 2  signals input to and output from the control centre are either. 3  which are part of the. , 4  or chemical signals. 5  the endocrine system.