The Nervous System

The Nervous system is divided into two parts:

1. The Central Nervous System is made up of the Brain and Spinal Cord

2. The Peripheral Nervous System is made up of all the nerve in the body.

The main cell of the nervous system is the ......... Neuron.

Problems in the Circulatory System

This is a video on common problems in the Circulatory System.

http://www.youtube.com/watch?v=_CZZWIqrb7M

Three types of cells found in the blood.

1. Red Blood Cells: carry oxygen to all the cells of the body.

2. White Blood Cells: help the body fight infection.










3. Platelets: aid in forming blood clots

The Circulatory System

Main function: The transportation of materials to all body parts. Nutrients from digestion are carried to the cells and wastes are carried away from the cells to be eliminated from the body.

There are 2 pathways of blood flow:

1. Pulmonary circulation: blood moves from the right ventricle of the heart to the lungs where the exchange of gasses occurs. The red blood releases carbon dioxide and picks up oxygen. Veins from the lungs return the oxygenated blood to the heart.

2. Systemic Circulation: Oxygenated blood is push out of the left ventricle to all parts of the body. The blood supplies all necessary material for cells to function and removes the waste products.

Pathway of the Circulatory System:

In pulmonary circulation: Blood flows from the right ventricle, to the lungs, and back to the left ventricle of the heart.

In systemic circulation: Blood is pumped out of the left ventricle into the aorta. The Aorta is the main artery out of the heart. Arteries carry blood away from the heart and have high pressure. Arteries get smaller as they move away from the heart. Capillaries are the smallest blood vessels and are only a single cell thick. This is where the exchange of oxygen and carbon dioxide happens. Veins are blood vessels that return the blood back to the heart.

Common Diseases in the Digestive System

There are many different diseases that occur in the digestive system.Some of the more common problems to be familiar with include:

1. Tooth decay- this condition is caused by bacteria in the

mouth breaking down the enamel on teeth.




2. Ulcers- sores that ocur in the linig of the stomach. They can be painful and bleed.

3. Diarrhea- this is the result of not enough water being absorbed in the large intestine. Dehydration can occur if too much water is lost.
4. Constipation- this condition occurs when feces stay in the large intestine too long. Often this is the result of not enough water or fiber in the diet.

The Digestive System

Main function : The taking in of food and breaking it down into usable nutrients.

There are 2 types of digestion:

1. Mechanical digestion takes place in the mouth where the teeth and tongue physically break food into smaller pieces.

2. Chemical digestion uses enzymes to chemically break down larger organic molecules into smaller, simpler molecules that can be used by the cells. This process starts in the mouth with saliva however, most chemical digestion occurs in the small intestine. In the small intestine, enzymes from the pancreas and bile made by the liver and stored in the gall bladder are added to the food.

Pathway of the Digestive System: Mouth, esophagus, stomach, small intestine, large intestine, rectum, anus

The Digestive System