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• Main Function: It releases hormones into the blood to signal other cells to behave in certain ways. It is a slow but WIDESPREAD form of communication.
• Main Function:It releases hormones into the blood to signal other cells to behave in certain ways. It is a slow but WIDESPREAD form of communication.
1. Endocrine glands: Release hormones DIRECTLY into the circulatory system
2. Hormones
Consists of:
Chemicals released in one part of the body that travel through the bloodstream and affect the
activities of cells in other parts of the body.
growth hormones
Hormone fits receptor on “target” cell
targetcell
non-targetcells
secretingcell can’t
readsignal
can’treadsignal
Pituitary Gland- “the Master Gland”
Hormone: Growth Hormone
1. Stimulates bones to elongate2. Affects metabolism
Pituitary Gland- Growth Hormone
Disorders: Oversecretion: In early childhood = GigantismIn adults = Acromegaly (bones of hands, feet and face enlarge)
Undersecretion:In childhood = Dwarfism Robert
Wadlow
Thyroid Gland
Hormone:Thyroxine
• Regulates metabolism (necessary for normal physical and
mental development)
ThyroxineDisorders: Oversecretion:Nervousness, weightloss
Undersecretion:In childhood, cretinism (mental retardation, small size)
GoiterIodine Deficiency in the diet
= an enlarged thyroid gland
Parathyroid GlandHormone:
ParathormoneControls metabolism of calciumNecessary for: • Nerve and Muscle function• Blood clotting• Health of Bones and Teeth
Parathyroid Glands
ParathormoneDisorders:
Undersecretion:• Nerve disorders• Brittle bones• Clotting disorders
Adrenal GlandHormones:
CortisoneRegulates carbohydrates, protein and lipid metabolism. (Promotes the change of lipid
and protein to glucose)
Adrenaline1. Raises blood sugar level2. Increases Heartbeat &
Breathing rate
CortisoneDisorders: Oversecretion:Cushing’s Disease – high blood glucose, excess of fat
Undersecretion:Addison’s Disease – low blood glucose,
weight loss
AdrenalineDisorders:
Undersecretion:Inability to deal with stress.
Pancreas: Islets of LangerhansHormones:
InsulinStimulates glucose
uptake by cells
GlucagonPromotes liver to change
glycogen to glucose
InsulinDisorders: Oversecretion: Low Blood Sugar
Undersecretion:High Blood Sugar = Diabetes
liver
pancreas
liver
blood sugar level(90mg/100ml)
insulin
body cells takeup glucose from blood
liver storessugar as glycogen
reducesappetite
glucagon
pancreas
liver releasesglucose
triggershunger
high
low
Regulation of Blood Sugar: Negative Feedback
After a meal Between meals
Negative Feedback: Nervous System
highlow
sweating
lowerstemperature
shivering
Body Temperature
raisestemperature
What about the Ovaries and the Testes?
• Don’t worry, we’re saving them for our unit on Reproduction
