THE HUMAN ENDOCRINE SYSTEM
the nervous and endocrine systems enable animals to respond to external changes and to control conditions inside their
bodies
Chemical co-ordination
chemical co-ordination is a slow, prolonged process of communicating information throughout the body by way of
chemicals called hormones
a variety of hormones are secreted by special glands or tissue called endocrine glands
the endocrine system works with the nervous system
What is a hormone?
^ a hormone is an organic chemical substance (usually a protein or steroid) secreted by an endocrine gland and carried in
the blood stream to its target organ(s) where it regulates metabolic reactions.
hormones do not last long in the body as they are broken down by enzymes
What is a target organ?
although hormones are carried in the blood throughout the body, they only affect certain cells
the specific cells that respond to a given hormone have receptor sites for that hormone
these cells are known as target tissue or target organs - they can be a single gland or organ or scattered throughout the
body
What is an endocrine gland?
,^ an endocrine gland is a vascular, ductless gland that secretes hormones which are carried in the bloodstream to their
target organs
> vascular -- richly supplied with blood vessels
Difference between endocrine and exocrine glands?
the secretions of an exocrine gland are carried in ducts to where they are needed (salivary glands, liver, pancreas)
endocrine glands do not have ducts and their secretions are carried in the bloodstream to their target organs
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ENDOCRINE GLANDS IN THE BODY
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HYPOTHALAMUS
the hypothalamus s the part of the brain situated above the pituitary gland
it secretes the hormone ADH -- anti-diuretic hormone
- What is the role of ADH?
osmoreceptors in the blood vessels of the hypothalamus detect an increase an the osmolarity (low water levels) of the
blood
the nervous and endocrine systems enable animals to respond to external changes and to control conditions inside their
bodies
Chemical co-ordination
chemical co-ordination is a slow, prolonged process of communicating information throughout the body by way of
chemicals called hormones
a variety of hormones are secreted by special glands or tissue called endocrine glands
the endocrine system works with the nervous system
What is a hormone?
^ a hormone is an organic chemical substance (usually a protein or steroid) secreted by an endocrine gland and carried in
the blood stream to its target organ(s) where it regulates metabolic reactions.
hormones do not last long in the body as they are broken down by enzymes
What is a target organ?
although hormones are carried in the blood throughout the body, they only affect certain cells
the specific cells that respond to a given hormone have receptor sites for that hormone
these cells are known as target tissue or target organs - they can be a single gland or organ or scattered throughout the
body
What is an endocrine gland?
,^ an endocrine gland is a vascular, ductless gland that secretes hormones which are carried in the bloodstream to their
target organs
> vascular -- richly supplied with blood vessels
Difference between endocrine and exocrine glands?
the secretions of an exocrine gland are carried in ducts to where they are needed (salivary glands, liver, pancreas)
endocrine glands do not have ducts and their secretions are carried in the bloodstream to their target organs
_____________________________________________________________
ENDOCRINE GLANDS IN THE BODY
, ___________________________________________________________
HYPOTHALAMUS
the hypothalamus s the part of the brain situated above the pituitary gland
it secretes the hormone ADH -- anti-diuretic hormone
- What is the role of ADH?
osmoreceptors in the blood vessels of the hypothalamus detect an increase an the osmolarity (low water levels) of the
blood
