Maintaining Homeostasis

By Martin Samaj
• Blood, and tissue fluid derived from blood, flow
around or close to all cells in the body
• Blood and tissue fluid form the internal
environment of the body
• This internal environment is controlled and varies
very little despite large variations in the external
• The control process is called homeostasis
• Homeostasis is maintaining the internal
environment of the body between limits
Parameters controlled by homeostasis
• The human blood usually stays within certain limits for
many physiological variables including:
• Body temperature
• Blood ph
• Carbon dioxide concentration
• Blood glucose concentration
• Water balance
The nervous system and the endocrine system are both
involved in controlling the internal environment. The
endocrine system consists of glands, which release
hormones that are transported in the blood
Endocrine and nervous system
Negative feedback mechanism
• The physiological changes that bring a value
back closer to a set point are called negative
feedback mechanism