1. Homeostasis Which systems control body functions?
How does your body stay in balance?

2. Which systems control body functions?
The nervous system and endocrine system work together to control body functions
Glands are organs that release chemical signals directly into the blood stream

3. Nervous system
A signal in the environment that makes you react is called a stimulus
A response is what your body does in reaction to a stimulus

4. Endocrine system
The chemical signals released by the endocrine system are called hormones
One hormone controls the amount of water in the blood
One hormone controls the amount of sugar in the blood

5. How does your body stay in balance?
Homeostasis is the condition in which an organisms internal environment is kept stable in spite of changes in the external environment

6. Regulating temperature
When you are cold, your nervous system sends signals to make you shiver
When you are hot, you endocrine system releases hormones that make you perspire
Changes in the amount of blood flow to the skin helps prevent heat loss

7. Meeting energy needs
If your body needs more energy, hormones from the endocrine system signal the nervous system to make you feel hungry
Your digestive system, and circulatory system also play major roles

8. Maintaining water balance
If your body needs more water, you feel thirsty
Excess water is released through excretory system when you exhale, sweat, or breathe.

9. Ongoing stress can disrupt your body’s ability to fight disease
Responding to stress
Stress is the reaction of your body to possibly threatening, challenging, of uncomfortable events
Ongoing stress can disrupt your body’s ability to fight disease

10. Fighting disease
The immune system includes specialized cells that can attack and destroy viruses, and bacteria
Fighting disease requires more energy causing your body temperature to go up

11. Identify the main systems involved:
Sweat appears on the surface of the runners skin, and carbon dioxide moves rapidly out of her lungs. Cell wastes ,move into her blood and are filtered by her kidneys

12. Which systems?
Food from the runner’s breakfast has been broken down into nutrients and is delivered to cells

13. Which systems?
A runner’s brain interprets what her eyes see and directs her movements

14. Which systems?
Hormones move through the runner’s bloodstream, stimulating her body systems to work harder

15. Which systems?
The runners breathing rate and heart rate increase, supplying more oxygen to her muscle cells