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Homeostasis/Endocrin
Definitions of key words
| Term | Definition |
|---|---|
| Homeostasis | The maintenance of a constant internal environment |
| Stimulus | A 'change' in the internal or external environment |
| Sensor | The part of the body that detects a change in conditions either external or internal |
| Communication System | The part of the body that receives signals from sensors and reacts in a way that will change the conditions |
| Effector | The actions that are carried out that will effect a change in conditions |
| Response | The result of the actions of the effectors |
| Ectotherm | An organism that cannot maintain it's own body temperature |
| Endotherm | An organism that can maintain it's own body temperature |
| Negative feedback | The effectors are 'switched off' due to conditions returning to optimum (normal) |
| Positive feedback | The effectors are NOT 'switched off' and conditions will continue to be out of control (worsen) |
| Endocrine system | Collection of glands of an organism that secrete hormones directly into the circulatory system to be carried towards a distant target organism. |
| Hormone | A chemical messenger |
| Endocrine gland | A gland that secretes substances directly into the blood |
| Exocrine gland | A gland that secretes substances directly into a duct |
| Target tissue | The tissue that is affected by a particular hormone |
| Pancreas | An organ that contains both endocrine and exocrine tissue |
| Insulin | A hormone that lowers the amount of glucose in the blood |
| Glucagon | A hormone that raises the amount of glucose in the blood |
| Hepatocytes | Liver cells |