1. Mechanisms of Homeostasis

2. Homeostasis
Process where the body maintains a constant internal environment
Reactions & enzymes work best in specific conditions
Control systems adjust to internal/external changes
pH, temp, fluids

3. Control Systems Sensors (aka: receptors)
!*%!?%&#
Sensors (aka: receptors)
Gather information about the body and environment
Ex: skin senses pressure
Communication Center
Messages sent throughout the body to respond
Ex: Impulse travel through your nerves
Control Center
Receives information from the sensors
Ex: Brain interprets the impulse
Targets
Body part that changes its activity
Ex: Muscles in foot stretch/contract abruptly

4. Negative Feedback Loops
Regulates most of the body
Counters changes in the body that move conditions away from a set point
Reverses the change
Keeps internal environment stable

6. Positive Feedback Loop
Increases the changes away from set points
Important when rapid changes needed
Ex: Oxytocin released
When uterus contractions begin, oxytocin released to speed up the contractions (not stop them)

7. Working Together Thermoregulation: Maintenance of body temperature
Skin: sensors provide feedback to brain
Nervous & Endocrine system: send messages to/from brain
Muscles: Start to shiver

8. Homeostasis disruption
Sensors fail
Wrong messages sent
Message doesn’t reach target
Serious injury
Microorganism infection
Short Term
Temporary discomfort (usually)

9. Long Term: Diabetes Normally Insulin controls glucose level in blood
When high glucose: more insulin released
When low glucose: less insulin released
Type 1
Pancreas unable to make insulin
Glucose in blood rises
Blood pH decreases (more acidic)
Type 2
Excess glucose level in blood rises
Not enough insulin produced

10. Kobe Kuiz Define homeostasis.
Name and describe the four parts of the “control system.”
What is negative feedback?
What is positive feedback?
Is the following example positive or negative feedback?
During heavy exercise your body loses water when you sweat. As a result of water loss, your body redirects the remaining water inside your body to vital parts of your body to replenish these vital organs.
What is diabetes?
How does Type I and Type II diabetes differ?