1. The Endocrine System
Chapter 36

2. ENDOCRINE GLANDS

5. ENDOCRINE SYSTEM:
Set of hormone secreting glands within an animal’s body
ENDOCRINE GLAND:
Is a ductless gland that makes & secretes specific chemical messengers (hormones) into the blood

6. EXOCRINE GLAND:
Secretes their chemicals into ducts that carry them to their destination eg sweat gland, salivary gland, gastric gland
HORMONE:
Is a chemical messenger secreted by an endocrine gland into the blood which distributes it through out the body altering the activity of specific target tissues

7. GLAND
HORMONE
FUNCTION
pituitary
ADH
Anti diuretic hormone
Growth hormone
Thyroid stimulation hormone TSH
Increases H2O absorption in the kidney
Speeds up growth
Causes thyroid gland to secrete thyroxine increasing cell metabolism

8. GLAND
HORMONE
FUNCTION
Pituitary
Thyroid
Gonad stimulating hormone GSH
Thyroxine
Stimulates gonads (ovaries & testes) to secrete sex hormones
Regulates metabolism, growth & development

9. GLAND
HORMONE
FUNCTION
Adrenal
Pineal
Pancreas
Adrenaline
Melatonin
insulin
Prepares the body for emergency responses
Controls body rhythms
Regulates the amount of sugar in the blood

10. GLAND
HORMONE
FUNCTION
Thymus
Ovaries
Testes
Parathroids
Thymosine
Oestrogen
& progesterone
Testosterone
Parathorome
Matures WBC
Controls sexual development
Controls release of Ca from bones into blood plasma

11. Differences between endocrine & nervous systems
ENDOCRINE SYSTEM
Electrical – chemical message
Chemical message
Carried by nerves
Carried by blood
Impulses target specific sites
Messages can be sent to many regions in the body
Response is fast acting
Response is slow acting
Effects are short term
Effects are long term

12. Growth Hormone Deficiency Symptoms:
Lower than normal height, immature face
Excess symptoms:
Over enlargement of body tissue including bones in hands, feet, face & skull
Corrective measures: (for deficiency)
Injections of growth hormone

13. Hormone Supplements– know 2
Growth hormone can be used as a body building supplement
Oestrogen can be used to regulate the menstrual cycle
Insulin in the treatment of diabetes
HRT hormone replacement therapy to reduce the effects of the menopause

14. Negative feedback control of thyroxine levels – HIGHER LEVEL ONLY
When the level of thyroxine is LOW, thyroid releasing hormone TRH is produced by the hypothalmus
This causes the release of thyroid stimulating hormone TSH in the pituitary
TSH stimulates the secretion of thyroxine

15. 4. When the amount of thyroxine reaches a certain level, the hypothalmus stops secreting TRH
When the level of thyroxine falls again the cycle repeats
This is an example of a negative feedback mechanism

16. THYROXINE control – Feedback