1. Unit 1 Homeostasis, Nervous System, the Senses, and the Endocrine System

2. Homeostasis Homeo Static Homeostasis
External environment changes drastically
Internal environment (inside our bodies) must stay the same
Homeo
Static
Homeostasis

3. Homeostasis
Homeostasis is the ability of an organism to maintain its internal environment.

4. Homeostasis
For your internal environment to remain constant you must have a
1. Monitor (detect the problem)
2. Control (fix it)

5. Homeostasis Example Oxygen concentration in blood.
Monitor = Oxygen chemoreceptor in aortic arch
Control = Medulla Oblongata
If not enough O2 in blood,
chemoreceptor detects problem
Medulla oblongata commands diaphragm & intercostals to work harder
Oxygen debt is soon solved
chemoreceptor stops detecting problem
Medulla Oblongata stops trying to fix it

6. This controlling method is called...
Negative Feedback

7. 1. Nerves 2. Hormones Homeostasis
our bodies use 2 mechanisms for controlling our internal make-up.
1. Nerves
and the nervous system
2. Hormones
and the endocrine system

8. First . . .
The Nervous System