THE ENDOCRINE SYSTEM
CLEMENT OKRAKU TETTEY
(Ph.D)
,• Endocrinology is the scientific study of hormones and the
endocrine organs
• The endocrine system is the second great control system of the
body
• Interacts with the nervous system to coordinate and integrate the
activity of body
• the nervous system regulates the activity of muscles and glands
via electrochemical impulses delivered by neurons
• The endocrine system influences metabolic activity by means of
hormones
2
,• There are two kinds of glands:
• Exocrine glands produce nonhormonal substances, such as
sweat and saliva, and have ducts that carry these substances to
a membrane surface
• Endocrine glands ( called ductless glands) produce hormones
and lack ducts
3
, DEFINITIONS
• Autocrines: chemicals that exert their effects on the same
cells that secrete them
• eg. smooth muscle cells release certain prostaglandins which
cause those same smooth muscle cells to contract
• Paracrines: chemicals that exert their effects on other cell
types which are close to the cells that secrete them
• Eg. somatostatin released by one type of pancreatic cells
inhibits the release of insulin by a different type of pancreatic
cells
4
CLEMENT OKRAKU TETTEY
(Ph.D)
,• Endocrinology is the scientific study of hormones and the
endocrine organs
• The endocrine system is the second great control system of the
body
• Interacts with the nervous system to coordinate and integrate the
activity of body
• the nervous system regulates the activity of muscles and glands
via electrochemical impulses delivered by neurons
• The endocrine system influences metabolic activity by means of
hormones
2
,• There are two kinds of glands:
• Exocrine glands produce nonhormonal substances, such as
sweat and saliva, and have ducts that carry these substances to
a membrane surface
• Endocrine glands ( called ductless glands) produce hormones
and lack ducts
3
, DEFINITIONS
• Autocrines: chemicals that exert their effects on the same
cells that secrete them
• eg. smooth muscle cells release certain prostaglandins which
cause those same smooth muscle cells to contract
• Paracrines: chemicals that exert their effects on other cell
types which are close to the cells that secrete them
• Eg. somatostatin released by one type of pancreatic cells
inhibits the release of insulin by a different type of pancreatic
cells
4
