Chapter 1 Lesson 3 Homeostasis

Ms. Schreurs

7th Grade Life Science

Human Body Systems

My Planet Diary

Worried Sick- Not Just an Expression

Page 18

How Does Your Body Stay in Balance?

• Conditions inside your body stay stable – Examples:

1. Chemical makeup of your cells

2. Water content

3. _________________

Homeostasis

= condition in which an organism’s internal environment is kept stable in spite of changes in the _______________

• All of your body systems working together maintain ______________ and keep the body in balance

Maintaining Homeostasis

• Regulating Temperature

– Changes to the amount of blood flow to skin also regulates ___________________

Meeting Energy Needs

• Hormones from the endocrine system signal the nervous system to make you feel hungry when you need energy

• Figure 2 page 20

Maintaining Water Balance

• Water you drink passes from digestive system to ____________________

• Excess water leaves body through your excretory system (exhale, sweat,

urinate)

Keeping Your Balance • Your ears help you balance

– Structures in your inner ear sense the _______________________

– Brain sends signals to your muscles when you are loosing your _______

Responding to Stress • __________= the reaction of your

body to possibly threatening, challenging, or uncomfortable events – Examples: heart beating fast, faster

breathing – Ongoing stress can disrupt

________________ • Example: your body many not

be able to fight disease as well

Fighting Disease

• Bacteria and viruses that cause disease can disrupt homeostasis and make you

sick

• Immune System=_________________ ______________________________ – Fighting infection causes

increased body temp, uses extra energy

Systems in Action

• Real-World Inquiry

Page 24-25

• Assess Your Understanding Page 25