science 8 xxx

Study Guide for Digestive and Respiratory Systems

1. Organs and Functions:

   - Digestive System: 

     - Mouth: Starts digestion.

     - Esophagus: Moves food to stomach.

     - Stomach: Breaks down food.

     - Small Intestine: Absorbs nutrients.

     - Large Intestine: Absorbs water and forms waste.

     - Rectum: Stores waste.

     - Anus: Excretes waste.

   - Respiratory System:

     - Nose/Mouth: Filters and moistens air.

     - Trachea: Transports air.

     - Bronchi: Leads to lungs.

     - Lungs: Site of gas exchange.

     - Alveoli: Exchange oxygen and carbon dioxide.

2. Pathway of Food:

   Mouth → Esophagus → Stomach → Small Intestine → Large Intestine → Rectum → Anus

3. Pathway of Air:

   Nose/Mouth → Trachea → Bronchi → Lungs → Alveoli

4. Role of Each System:

   - Digestive System: Breaks down food for energy and nutrients.

   - Respiratory System: Provides oxygen and removes carbon dioxide.

5. Site of Gas Exchange:

   - Oxygen enters bloodstream in alveoli; nutrients enter bloodstream in small intestine.

6. Smoking in the 1950s vs. Today:

   Smoking was accepted due to lack of knowledge about health risks. Now it’s known to cause serious health problems.

7. Labeling Organ Systems:

   Be ready to label the digestive and respiratory organs on a diagram.

8. Diffusion:

   - In the lungs, oxygen moves into blood; carbon dioxide moves out.

   - In the intestines, nutrients move into blood.