THE
ENDOCRINE
SYSTEM
, CHEMICAL CO-ORDINATION
• A process of communication information through the body by chemicals which are
called hormones.
• This enables animals to respond to
external changes and to control
conditions inside their body
• Hormones are secreted by special
glands or tissue - endocrine glands
HORMONES
• An organic chemical substance
• Usually a protein - sometimes a steroid
• Secreted by endocrine glands
• Carried in the blood stream to its
target organ/s
• Don’t last long in body - broken down
by enzymes
TARGET ORGAN:
• Hormones only a ect certain cells
• The speci ic cells that respond to a
certain hormone have receptor sites
for that hormone
• These cells are known as the target organs / target tissue
ENDOCRINE GLAND
• Vascular, ductless gland
• Secreted hormones which are carried through blood stream to their target organ
• Vascular = richly supplied with blood vessels
DIFFERENCE BETWEEN EXO / ENDOCRINE GLANDS
• Exocrine gland secretions
are carried in ducts to
where they are needed
• Eg. Salivary glands,
pancreas
• Endocrine glands do not
have ducts
• Their secretions are
carried in blood stream to
the target organ
f ff
ENDOCRINE
SYSTEM
, CHEMICAL CO-ORDINATION
• A process of communication information through the body by chemicals which are
called hormones.
• This enables animals to respond to
external changes and to control
conditions inside their body
• Hormones are secreted by special
glands or tissue - endocrine glands
HORMONES
• An organic chemical substance
• Usually a protein - sometimes a steroid
• Secreted by endocrine glands
• Carried in the blood stream to its
target organ/s
• Don’t last long in body - broken down
by enzymes
TARGET ORGAN:
• Hormones only a ect certain cells
• The speci ic cells that respond to a
certain hormone have receptor sites
for that hormone
• These cells are known as the target organs / target tissue
ENDOCRINE GLAND
• Vascular, ductless gland
• Secreted hormones which are carried through blood stream to their target organ
• Vascular = richly supplied with blood vessels
DIFFERENCE BETWEEN EXO / ENDOCRINE GLANDS
• Exocrine gland secretions
are carried in ducts to
where they are needed
• Eg. Salivary glands,
pancreas
• Endocrine glands do not
have ducts
• Their secretions are
carried in blood stream to
the target organ
f ff
