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LIFE SCIENCE GRADE 12
THE ENDOCRINE SYSTEM
AND HOMEOSTASIS
NOTES
1
, The endocrine system
Key words:
1.The endocrine gland- type of gland which pours its secretion’s directly into the blood
Example of an endocrine gland: Hormones are an example of an endocrine gland
since they pour their secretions directly to the blood.
2. The exocrine gland- type of gland which pours its secretions directly into the duct
Example: sperm duct, sweat gland, salivary glands etc. these types of glands pour their
secretions directly into the duct
3. Hormones- these are chemical messenger’s which are protein in nature
. Differences between the endocrine system and the nervous system
Endocrine system Nervous system
Messages are transmitted as HORMONES Message is transmitted as NERVE IMPULSE
BY NEURONS
Takes a long time to react e.g. puberty may Responds quickly to impulses
take years
Targets a wider area Targets a specific area
Hormones control long term changes Nerve impulse controls short term changes
NB: everything inside the endocrine system is regulated by hormones and regulatory organs
/target organs.
2
LIFE SCIENCE GRADE 12
THE ENDOCRINE SYSTEM
AND HOMEOSTASIS
NOTES
1
, The endocrine system
Key words:
1.The endocrine gland- type of gland which pours its secretion’s directly into the blood
Example of an endocrine gland: Hormones are an example of an endocrine gland
since they pour their secretions directly to the blood.
2. The exocrine gland- type of gland which pours its secretions directly into the duct
Example: sperm duct, sweat gland, salivary glands etc. these types of glands pour their
secretions directly into the duct
3. Hormones- these are chemical messenger’s which are protein in nature
. Differences between the endocrine system and the nervous system
Endocrine system Nervous system
Messages are transmitted as HORMONES Message is transmitted as NERVE IMPULSE
BY NEURONS
Takes a long time to react e.g. puberty may Responds quickly to impulses
take years
Targets a wider area Targets a specific area
Hormones control long term changes Nerve impulse controls short term changes
NB: everything inside the endocrine system is regulated by hormones and regulatory organs
/target organs.
2