Endocrine physiology
- Hormones are blood borne messengers
- Produced by one organ
- Secreted into the blood
- Carried to all parts of the body by the blood
- Only those organs having the specific receptors respond to the
hormone
- Rapidly destroyed
- Involved in homeostasis and adaptation
- Some hormones control the activity of other endocrine glands
- Examples include hormones produced by the anterior pituitary gland
Control of salt, water and osmotic pressure
- Homeostasis requires close regulation of body salt & water
- ADH (antidiuretic hormone) causes water resorption in the collecting
ducts of the kidney
- Aldosterone increases Na reabsorption by the kidney
- If the blood osmotic pressure is increased ADH secretion is
increased
- If the blood volume falls aldosterone production in the renal cortex
will increase
- A number of hormones are involved in the control of Ca
Reproductive function
- Growth of the ovaries and testes and secretion of sex hormones is
controlled by FSH and LH
- Oxytocin produced by the posterior pituitary causes contraction of
uterine muscles
- Milk production involves many hormones, including prolactin
- Milk ejection when the baby suckles is controlled by oxytocin
Growth and metabolism
- Thyroxin increases the metabolic rate of many tissues
- Several hormones aid metabolism by raising blood glucose including
- Glucagon
- Adrenaline
- Cortisol
- Growth hormone
- Insulin lowers blood glucose
- Erythropoietin supports metabolism by regulating the number of red
cells in the blood
- Important hormones regulating growth include
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