Global Warming

Respiratory System

The main function of the respiratory system is gas exchange. Carbon dioxide is carried to the lungs in erythrocytes and released, then the erythrocytes collect oxygen and deliver this essential gas to our bodies. The mucus in the respiratory system helps to protect it as well as to carry debris out of the respiratory tract, which is assisted by the movements of little hair like structures called cilia. Smoking causes the cilia to stop working and that is why smokers have coughs. It takes 28 days for the cilia to wake up and start working again after someone quits smoking. The cilia also help remove pollution. The main function of the respiratory system is to discard waste in the form of carbon dioxide and to take in oxygen.

Circulatory System

* Transport gases, like oxygen from the lungs to cells around the body and carbon dioxide from the cells to the lungs.

* Transport nutrients like glucose.

* Transport wastes from cells to organs that play the role of eliminating them.

* It contains cells that fight infections and defend against foreign bodies.

* Maintains the pH levels and ionic concentration of fluids in the body.

* Helps maintain the body temperature, this is especially important in warm blooded animals like humans.

Digestive System

The primary function of the digestive system is to break down the food we eat into smaller parts so the body can use them to build and nourish cells and provide energy.

The digestive system is a series of hollow organs joined in a long, twisting tube from the mouth to the anus. Inside this tube is a lining called the mucosa. In the mouth, stomach, and small intestine, the mucosa contains tiny glands that produce juices to help digest food.

Two solid organs, the liver and the pancreas, produce digestive juices that reach the intestine through small tubes. In addition, parts of other organ systems...