Biology

 Like the road system, the cardiovascular system has a left side and a right side. In the cardiovascular system, after the blood travels through the whole body, it comes back to where it started. A road system is similar, reaching the destination before returning to where it started. In the cardiovascular system, there are different parts, like the arteries, veins and others. In the road system, there are straight roads, curved roads, roundabouts and others. In the cardiovascular system, after the blood passes through a valve, there is no way it can go back, and it has to travel around the whole body it is at the valve again. In the road system, however, a car can make u-turns at certain places along the road and go back, instead of having to go around the whole system before it reaches the place again. 1. What three functions does the cardiovascular system perform?

Delivery of materials to parts of the body, removing waste and fighting disease.

2. Distinguish between substances that the cardiovascular system transports to cells and substances that it transports away from cells.

Substances that are needed like oxygen are transported to the cells, while waste like carbon dioxide are transported away from the cells.

3. List four chambers of the heart. What structures in the heart separate one chamber from another?

The four chambers of the heart are the right atrium, right ventricle, left atrium, and left ventricle. The valves and the septum separate one chamber from another.

4. What function does the heart perform?

The heart pumps blood to parts of your body.

5. What would happen if the valve between the right atrium and right ventricle did not work properly?

Some blood would go back from the right ventricle to the right atrium through the valve, causing the heart to not function as effectively.

6. Where does blood returning from the body enter the heart? b. Where does the blood move next?

It enters through the right atrium. The blood then goes to the right ventricle.

7. Review Figure 5. How does the blood in the artery leaving the right ventricle differ from the blood in the artery leaving the left ventricle? To where does the artery leaving the right ventricle carry blood?

The blood leaving the right ventricle is full of carbon dioxide and low on oxygen while the blood leaving the left ventricle is full of oxygen and low on carbon dioxide.

Digestive system This lesson is designed for you to use the Internet to learn about the digestive system. Type in the following address: [] Follow the instructions on the sheet to answer the questions. Remember to only click where the sheet tells you to.

1. What is digestion? A process in which food is broken down into chemicals that the body can use.

2. Click on **Mouth and Teeth**. What is the purpose of the teeth in the digestive system? The teeth help us digest the food by cutting it into parts and then grinding it.

3. What is **Saliva** used for and what helps it do it’s job? Saliva is used to soften the food that makes it easier for us to chew the food. Enzymes in the saliva helps breaking down the starch in the food.

4. Where does the food go next? It goes to the stomach through the esophagus.

5. What is the purpose of the **tongue** in the digestive system? The tongue pushes the food to the back of the mouth.

6. Click on **Next** at the bottom. Name 2 ways food is broken down in the stomach. The food is mixed with acids, and the muscles in the stomach move to break down the food.

7. How is the stomach protected? The stomach is protected from the acid by a lining.

8. Where does the food go next? The food goes to the small intestine next.

9. How long is it? The small intestine is about twenty feet long.

10. How does food move in the small intestine and what is this movement called? The food is squeezed down the small intestine and it is called peristalsis.

11. What are **villi** and what do they do? They are like fingers and they are found along the small intestine. Villi absorb the chemicals from the food into the body.

12. What is the last section of the digestive system called? Large intestine.

13. Click on **Next** at the bottom. Read the information and write down how each of the following three organs aid in digestion:
 * Pancreas:** The pancreas makes and inserts insulin into the blood. Insulin allows glucose or sugar to be absorbed from the food into the body.


 * Liver:** The liver makes bile, which is needed to break down fat.


 * Gall Bladder:** The gall bladder stores the bile made by the liver.

Mouth: The mouth cuts up the food.

Esophagus: The esophagus transports the food to the stomach.

Stomach: The stomach mixes the food with acid and churns it.

Small intestine: The small intestine absorbs the chemicals and nutrients into the body.

Large intestine: The large intestine absorbs the water from the food into the body.

Rectum: The rectum pushes all the remaining food to the anus.

Anus: Releases the remaining food from the body.