The Endocrine System

1
The Endocrine System

• Chapter 36

2
ENDOCRINE GLANDS
3
(No Transcript)
4
(No Transcript)
5
ENDOCRINE SYSTEM Set of hormone secreting
glands within an animals 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 sexual development Controls release of Ca from bones into blood plasma
11
Differences between endocrine nervous systems
NERVOUS SYSTEM 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

1. Growth hormone can be used as a body building
   supplement
2. Oestrogen can be used to regulate the menstrual
   cycle
3. Insulin in the treatment of diabetes
4. 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