Lab 18: endocrine system and negative feedback

homeostasis

our bodies maintain constant internal environment

endocrine glands

the organs of the endocrine system (duct-less gland, straight to blood stream)

hormones

• chemical messengers directly into the blood stream

  • target tissues or cells

1. absorption

intestines absorb glucose after a meal

2. glucose

blood glucose level rises

3. pancreas

pancreas responds to high glucose level by secreting insulin

4. insulin

insulin causes liver and other tissues to take up glucose, which removes it from the bloodstream

5. levels drop

• blood glucose level drops, homeostasis is restored

• trigger for insulin secretion is no longer present

• pancreas stops insulin secretion