Chapter 9 - The Endocrine System
Second controlling system of the body, the nervous system is the fast-control system
Uses chemical messengers (hormones) that are released into the blood
Hormones control several major processes
Reproduction
Growth and development
Mobilization of body defenses
1
, Maintenance of much of homeostasis, like insulin and glucagon
Regulation of metabolism, like thyroxine
Types of glands
Endocrine (ductless)
Only produces hormones
Exocrine (have ducts)
Produces anything but hormones
Hormones are produced by specialized cells
Cells secrete hormones into extracellular fluids
Blood transfers hormones to target sites
These hormones regulate the activity of other cells
Endocrinology is the scientific study of hormones and endocrine organs
2
, The Chemistry of Hormones
Hormones are classified chemically as
Amino acid–based, which includes
Proteins
Peptides
Amines
Steroids: Made from cholesterol
Prostaglandins: Made from highly active lipids that act as local hormones, they're
important for a lot of activities in the body
Hormone Action
Hormones affect only certain tissues or organs (target cells or target organs)
Target cells must have specific protein receptors
Hormone binding alters cellular activity
Permeability
Production of enzymes or hormones
Stimulates cells to divide
3
Second controlling system of the body, the nervous system is the fast-control system
Uses chemical messengers (hormones) that are released into the blood
Hormones control several major processes
Reproduction
Growth and development
Mobilization of body defenses
1
, Maintenance of much of homeostasis, like insulin and glucagon
Regulation of metabolism, like thyroxine
Types of glands
Endocrine (ductless)
Only produces hormones
Exocrine (have ducts)
Produces anything but hormones
Hormones are produced by specialized cells
Cells secrete hormones into extracellular fluids
Blood transfers hormones to target sites
These hormones regulate the activity of other cells
Endocrinology is the scientific study of hormones and endocrine organs
2
, The Chemistry of Hormones
Hormones are classified chemically as
Amino acid–based, which includes
Proteins
Peptides
Amines
Steroids: Made from cholesterol
Prostaglandins: Made from highly active lipids that act as local hormones, they're
important for a lot of activities in the body
Hormone Action
Hormones affect only certain tissues or organs (target cells or target organs)
Target cells must have specific protein receptors
Hormone binding alters cellular activity
Permeability
Production of enzymes or hormones
Stimulates cells to divide
3
