General Introductory Notes: |
Basic summary notes about the endocrine
system include:
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Hormones are 'chemical messengers'.
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Hormones have 'target organs'.
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Endocrine glands are ductless glands that secret
hormones directly into the blood. |
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Functions of Hormones: |
1.
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Hormones help to regulate:
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Volume and Chemical Composition
of Extra-Cellular Fluid. |
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Metabolism |
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Biological Clock (Circadian Rhythms) |
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Glandular Secretions |
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Contraction of smooth and cardiac muscle fibres |
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Some immune system activities. |
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2.
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Hormones control growth and development.
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3.
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Hormones govern the opertation of reproductive
systems.
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Comparison between the Endocrine System and the Nervous
System: |
1. |
Hormones are transported around (to
their target organs) the body by the
blood.
Therefore hormonal responses are relatively slow
compared with nervous responses. |
2. |
Many hormonal responses (e.g. growth) occur over
relatively long periods of time. |
3. |
The main purpose of the Endocrine System is to
maintain Homeostasis
within the body (that is, to keep
the internal environment constant/within
balance), whereas
the key function of the Nervous System is to receive
and respond to stimuli.
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4. |
Generally, the endocrine system is controlled
by the Nervous System (through the Hypothalamus,
mediated by the Pituitary Gland). |
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