Mucus

• Normally, adults produce around 4 cups of mucus each day just from the sinus cavities and nose. It is also produced in other parts of the body. Mucus flows from the nasal passages down the throat, to the stomach. Cilia, tiny hairs on the cells in the mucous membranes, "push" the mucus along.
  Mucus in the nose serves as a sticky barrier to trap the germs, pollutants, allergens, bacteria and viruses we inhale. As you inhale them, mucus collects them and you swallow them along with the mucus, where they pass harmlessly through the digestive system.
  
  

Mucus Production

• Mucus is produced by mucous membranes, which are found throughout the human body. Mucous membranes are made up of a combination of cells that create a slippery lining on all of the passages that connect your inner body to the outside world, such as the tunnels of your ears, mouth, nose and digestive tract.
  
  One of the cells that makes up the mucous membrane is the Goblet Cell. This cell has one job: to make mucin. The goblet cell packages the mucin in little sacks, called vesicles. Vesicles surround each cell that makes up the mucous membrane and then fuse with the outer layers of the cells. The act of fusing releases the mucin. The mucus membrane consists of almost 95 percent water, and once released, the mucin soaks it up, expanding up to 600 times its original size and becoming mucus.
  
  

Mucus Function

• The primary function of all mucus in your body is to protect your organs by covering them with a sticky coating that will trap harmful substances. However, there are other functions that mucus serves. Mucus prevents your nose and throat from drying out. It humidifies the air you breathe. It makes food easier to swallow. Mucus also lines your intestines, making it easier to expel waste materials.
  
  Mucus is also in our lungs, smoothing our airways and trapping potentially harmful viruses and bacteria that try to invade our lungs. In fact, mucus production in our lungs is one of the primary causes of coughing. When we cough, we expel those harmful germs, and sometimes a little mucus with them!