1. Year 9 Science
Strathcona BGGS

2. The Endocrine System
 Consists of glands that produce chemicals
that act as messengers or signals.
 These are known as hormones.
 Hormones are released into and carried by
the blood stream.
 Changes produced by hormones are
generally:
 Slow
 Long term
 Irreversible
 Including:
 Growth
 Reproduction

3. Parts of the Endocrine System

4. The Pituitary Gland
 Is sometimes called the
‘Master Gland’ as it
regulates most other
endocrine glands.
 Releases hormones
including:
 Growth Hormone (GH)
 Thyroid Stimulating
Hormone (TSH)

5. The Thyroid Gland
 Is responsible mainly for
the regulation of
metabolic rate
 Major hormone:
 Thyroid Hormone

6. The Islets of Langerhans
 Are groups of cells in the
pancreas
 Regulate blood sugar
levels
 Releases hormones
including:
 Insulin – lowers blood
sugar levels
 Glucagon – raises blood
sugar levels

7. The Adrenals
 Located on top of the
Kidneys
 Has two layers
 The outer cortex
 secretes a lot of hormones.
 The most important are
aldosterone and cortisol
 the inner Medulla
 Releases adrenaline and
noradrenaline - key hormones
of the stress response

8. The Ovaries
 Release the female sex
hormones:
 Estrogen
 stimulates the development of
female secondary sexual
characteristics
 involved in monthly preparation for
pregnancy
 Progesterone
 stimulates the growth of mammary
glands
 prepares the uterus for pregnancy

9. The Testes
 Secretes the male sex Hormone:
 Testosterone
 very important in the development of a
male embryo.
 stimulates the development of male
secondary sexual characteristics

10. The Nervous System vs. The Endocrine System
The Nervous System The Endocrine System
 Uses (mostly) Electrical  Uses Chemical Messages
Messages (Hormones)
 Fast Acting  Generally Slow Acting
 Reversible changes  Generally Irreversible changes
 Dedicated signal system  Uses Blood System to spread
(nerves) hormones