1. THE ENDOCRINE SYSTEM

2. Endocrine System
Communication system that uses chemicals called hormones to send messages through the body.
Works with the nervous system

3. Hormones Substance secreted into blood stream by a gland
Acts on a target organ elsewhere in the body
Alter cellular activity, so have ability to alter metabolic rate
Classified as
Steroids
Proteins
Brain controls secretion of endocrine glands which regulates function of internal organs

4. Endocrine Glands Secrete directly into the bloodstream
Do not have ducts
Hypothalamus
Part of nervous system
Regulates the pituitary gland
Produces releasing and inhibiting hormones

5. Endocrine Glands 2. Pituitary Gland Located at base of brain
Divided into 2 lobes
Called the master gland

6. Endocrine Glands 3. Pineal Gland Located in centre of brain
Secretes melatonin
Sleep/awake hormone

7. Endocrine Glands 4. Thyroid Gland Just below larynx Has two lobes
Secretes thyroxine and calcitonin

8. Endocrine Glands 5.Parathyroid Glands
Four tiny glands in posterior wall of thyroid
Secretes parathyroid hormone ( PTH )

9. Endocrine Glands 6.Thymus Upper thorax behind sternum
Protects the body from infection
Produces thymosin

10. Endocrine Glands 7. Pancreas Is both endocrine and exocrine gland
Mainly a digestive gland
Secretes insulin and glucagon from groups of cells called Islets of langerhans

11. Endocrine Glands 8. Adrenal Gland Attached to upper part of kidneys
Secretes aldosterone which is involved in control of blood pressure
Secretes cortisol enabling body to cope with stress
Secretes DHEA which stimulates male secondary sexual characteristics
Secretes adrenaline at times of emotional or physical stress

12. Endocrine Glands

13. Endocrine Glands 9. Gonads The sex glands Ovaries in female
Testes in male
Hormones excreted are progesterone, oestrogen and testosterone
These hormones maintain the reproductive system and develop sexual characteristics

14. Endocrine Glands

15. Exocrine Glands
Secrete their products into ducts which open onto a surface
Examples are
Sweat glands
Salivary glands

16. Diabetes Mellitus Most common endocrine disease
Caused by disturbance of hormonal control and level of glucose in blood
Type 1 starts in childhood but can occur when older
Autoimmune disease
Person’s immune system destroys insulin produced by pancreas
High level of glucose, ( hyperglycaemia ), causes person to have polyuria and thirst ( polydipsia )
Treated with insulin

17. Diabetes Mellitus Type 2 Usually appears at later age
Often associated with obesity, can run in families
Problem is lack of insulin
Can be treated often with weight reduction and dietary changes
Some people require medication