1. The ability to maintain a constant internal environment
Homeostasis
The ability to maintain a constant internal environment

2. Regulation by chemical messengers
Hormones release by endocrine glands
Neurotransmitters released by neurons
Dendrite
Endocrine gland
Axon
Neurotransmitter
Hormone
carried
by blood
Receptor
proteins
Neuron
Problem with Type 2 Diabetes
The receptors have lost
sensitivity to insulin
So is the answer to give the person more insulin?
Target cell

3. Negative Feedback Loop
a type of biological regulation that acts in the opposite direction, to get something
that is either registering as too high or too low back to its normal level.
Sun goes down
Hypothalamus in the brain compares against 98.6˚F (set point)
Thermoreceptors sense temperature decrease
Body Temperature
Body Temperature
Calcium Levels
Osmolarity
You get goose bumps, your blood vessels constrict and you shiver

4. Positive Feedback Loop
a type of biological response that causes an amplification in the same direction
Baby moves toward cervix stretching tissue
Hypothalamus stimulates pituitary gland to release the hormone oxytocin
Stretch Receptors
are stimulated
Cervical tissue tension
Smooth muscle in uterus wall contracts
Other examples:
Lactation
Nerve signal (“All-Or-None”)

5. Negative Feedback for Temperature Regulation
Thyroid Gland produces Thyroxine - causing
Vasodilation
Hypothalamus
Cooling
Sweating
Vasoconstriction
Hypothalamus
Warming
Goose Bumps, then Shiver

6. Regulating blood sugar levels
beta islet cells
triggers uptake of glucose by body cells
triggers storage of glycogen in liver & muscle cells
- suppresses appetite
pancreas
- triggers conversion of glycogen to glucose by liver/muscles
- stimulates appetite
pancreas
alpha islet cells

7. https://science360.gov/obj/video/389d421f-8e6a-4cc4-bc5c-8d08abf8bbdc/chemistry-fear-fright