Sputum is mucus secreted by the glands in the airways of the lungs. Airway mucus consists of 3 main parts. The lower layer, called the sun phase or periciliary layer , is adjacent to the airways. This layer contains cilia, hair-like structures that dislodge mucus from the airways into the throat. The cilia are surrounded by water and electrolytes.
Above the periciliary layer is a thin layer of lipids (oil) and proteins. This layer, known as surfactant, is a substance secreted by the airways to reduce friction, which in this case helps the upper layer of mucus to spread more easily through the airways.
The top layer of mucus is a gel that mainly consists of water combined with mucin to make the water gel. Mucin is secreted by goblet cells, which are found next to the cilia in the periciliary layer .
What phlegm is not?
Although the body produces different types of mucus, phlegm is not mucus or mucus produced and expelled from the nasal passages as in rhinitis or postnasal drip . However, phlegm may contain some runny nose if the phlegm is secreted during a runny nose .
Normal function of mucus in the airways.
When the airways function normally, mucus accumulates particles and debris in the airways. The cilia in the airways then push the mucus into the throat, counterattacking with undulating motions. Once the mucus reaches the level of the throat, it tends to swallow it unknowingly, where it is digested in the stomach. This is one of the most important ways to protect your lungs .
What does the color of my sputum tell me?
There are false rumors that you can tell by the color of your sputum whether you need antibiotics or not. This is definitely not the case. However, here is what the color of your sputum can tell you :
- Sputum that is bright red or dark red , also known as hemoptysis , is usually fresh or old blood, respectively.
- Pink foamy sputum usually indicates pulmonary edema (fluid and swelling in the lungs).
- White or yellow phlegm occurs when your body's immune system cells begin to fight an infection, regardless of the source (bacterial or viral).
- Green sputum can result from an infection.
- Black sputum, also known as melanoptism , can be caused by coal miners' pneumoconiosis. This is because charcoal dust enters the lung tissue.
More than a few teaspoons of blood is an emergency and you should seek immediate medical attention. Very often, you will see sputum stained with blood, which may indicate an ongoing infection in the lungs.
Diseases that can affect phlegm
Many diseases can affect sputum production. This is usually due to changes in the lower layer of mucus that affect the movement of phlegm down the throat, or due to changes in the thickness (viscosity) of the phlegm. These changes may be due to conditions such as asthma , COPD , or cystic fibrosis .
When phlegm becomes thick, it is important to cough well to get the phlegm down your throat. If you can't move thick phlegm down your throat, you risk clogging your airways with phlegm. If you experience shortness of breath, you should seek immediate medical attention .
Medicines that can reduce the thickness of phlegm.
Thick phlegm can be difficult to pass. You can try the following types of medications :
- Antibiotics: if the cause is due to a bacterial infection.
- Expectorants: help to expel phlegm (such as guaifenesin)
- Mucolytic: thins mucus (as acetylcysteine)