Cheek cells are cells of the basal mucosa, which is the tissue that lines the inside of the mouth. Their primary role is to produce proteins called mucins, which are the basic component of mucus and help to keep the inside of the mouth moist. This is critical for the chewing, softening, swallowing, and digestion of food. Cheek cells also contribute to innate immunity by making up the oral epithelial barrier, which prevents pathogens from entering the bloodstream in the mouth.
What is a Cheek Cell?
Cheek cells (AKA buccal epithelial cells) make up the basal mucosa; i.e., the tissue that lines the inside of the mouth. Cheek cells are constantly shed from the buccal mucosa, and divide every 24 hours to compensate for this. They are easy to remove from the inside of the cheek using a swab, and can be viewed under a light microscope, so cheek cells are often studied in school laboratories.
Structure of Cheek Cells
A cheek cell is a good example of a typical animal cell, which is another reason for their popularity in school laboratories. Like all eukaryotic cells, cheek cells lack a cell wall. Instead, they are surrounded by a plasma membrane, which gives them a round, irregular shape. They contain a prominent nucleus and other membrane-bound organelles, such as mitochondria and endoplasmic reticulum.
Function of Cheek Cells
The cheek cells have two key functions. Their main job is to secrete mucins, which are a principal ingredient in mucus and help to keep the inside of the mouth moist. However, cheek cells are also part of the innate immune system and form a physical barrier against pathogens and toxins in the mouth.
The primary function of cheek cells is to secrete proteins called mucins, which are a key component of mucus. When combined with saliva from the salivary glands, mucins help to keep the interior of the mouth moist. This helps with the chewing, softening, enzymatic digestion, and swallowing of food. Therefore, cheek cells play a central role in initiating the digestion of food.
Protection Against Pathogens
Cheek cells make up the oral epithelial barrier inside the mouth, which is the body’s first line of defense against pathogens and toxins. Infectious agents that enter the mouth with food are unable to penetrate this barrier to enter the bloodstream. Instead, they are swallowed and ultimately destroyed by the strongly acidic conditions of the stomach.
Cheek Cells and DNA Testing
DNA testing is a laboratory technique used to analyze a person’s DNA and may be performed for a variety of reasons. For example, a DNA test may be used to confirm the parentage of a child, diagnose genetic disorders, or identify the perpetrator of a crime. Cheek cells are often used as a source of DNA, as they are easily obtained without any need for invasive procedures. They are constantly shed from the basal mucosa and can be painlessly removed by rubbing a cotton swab against the inside of the cheek.
Once a sample of cheek cells has been obtained, DNA is extracted from their nuclei and amplified using a polymerase chain reaction (PCR). The PCR creates millions or even billions of copies of the DNA molecules in the sample. This significantly increases the quantity of DNA, which makes it possible to analyze using other laboratory techniques.