1. Bell Ringer…
Put the following in order, from smallest to largest: organ, molecule, organelle, atom, organ system, tissue, organism, and cell
How might a health-care professional provide the basic requirements of life to an unconscious patient
Which characteristics of life does an automobile have? Why is a car not considered alive?

2. Homeostasis and System Integration
Interactions between organ systems

3. Organ systems are interdependent, interconnected, and packed together in a relatively small space

4. Due to this, the body has homeostatic regulation
Remember, a change in one level of organization can/will cause changes at all levels
Due to this, the body has homeostatic regulation

5. Homeostasis: refers to the existence of a stable internal environment
a variety of physiological mechanisms act to prevent potentially dangerous changes in the environment inside the body
survive, every living organism MUST maintain homeostasis

6. Homeostatic regulation:
adjustments in physiological system
that preserve homeostasis

7. Homeostatic regulation involves:
a receptor sensitive to a particular environmental change (stimulus)
a control center (aka: integration center) which receives and processes the information from the receptor
an effector, which responds to the commands of the control center and whose activity opposes or enhances the stimulus

8. Stimulus

9. Receptor
Control
Center
Stimulus
Effector
Activity occurs
Which enhances OR
Opposes the stimulus

10. Positive feedback:
when the initial stimulus produces a response that reinforces the stimulus
it is important in driving a potentially dangerous or stressful process to completion in a very rapid manner

12. Bell Ringer…. What is homeostasis?
Compare and contrast receptor and effector
What is another name for the control center
During a positive feedback mechanism, what happens to the stimulus?

13. Negative feedback:
when the initial stimulus produces a response the opposes the stimulus
usually ignore minor variations because they maintain a “ normal range” or “set point” rather than a fixed value
each person has their own individual homeostatic set points, therefore it is impractical to define “normal” homeostatic conditions very precisely
physiological values are reported either as averages or as a range that includes 95% or more of the sample population

15. When homeostatic regulation fails, organ systems begin to malfunction and the individual experiences the symptoms of illness.

16. Review… What is homeostasis?
What is the difference between negative feedback and positive feedback?
What are the parts of homeostasis regulation?

17. Review of Homeostasis…
When we begin to become dehydrated, we usually become thirsty, which causes us to drink fluids. On the basis of what you now know about control systems, decide whether the thirst sensation is part of a negative or positive feedback control system and defend your choice

18. More review of homeostasis…
When a person is diagnosed as diabetic, they no longer produce the proper amount of insulin need by the body. This is due to a break down in homeostasis.
Explain how homeostasis works with keeping our insulin levels ~ 90mg/100mL when the level becomes too high
The organs involved in this process are:
Pancreas – releases insulin into the blood
Liver – takes up glucose and stores it
Brain – decides what to do

19. On Your Own…
Describe a homeostatic mechanism that helps regulate blood pressure