Human Mouth

When it comes to digestion, the mouth is where it all begins. The mouth is the gate that opens so we can begin the process of energy absorption called digestion. But the mouth has other functions too. Along with digestion the mouth is also vital in respiration and communication.

Our mouths are just as unique as the individual who has it. No two people on earth have the same teeth. The tongue contains around 10,000 taste buds. The tongue also has a “print” that like fingerprints are unique to the individual.

Structure of Human Mouth

The mouth contains some of the strongest muscles in the human body. One of these muscles is the tongue. The tongue is the pound for pound strongest muscle a human possesses. It is also the only muscle that is only attached at one end.

human mouth anatomy

Looking inside the mouth we can see the following:

Lips

Lips form the border of our mouth. Lips are a different color than the rest of our face because the skin around them is much thinner.

Teeth and Gums

The teeth are used to break up the foods that we eat. Teeth are made from enamel, the hardest substance found in our body. Only about ⅓ of the tooth is visible while the rest sits below the gumline. Teeth contain their own blood vessels and nerves.

Tongue

The tongue contains taste buds and sensory receptors. This is often the first sensory organ that we use as humans to learn about the world around us. Which is why we see infants always putting things in their mouths.

Frenulum Linguae

This thin connective tissue attaches our tongues to the bottom of our mouth. Its because of this that humans can not swallow their tongue.

Hard Palate

This is a hard bone like structure that sits toward the front of the mouth. It acts to separate the oral cavity from the nasal cavity.

Soft palate

The soft palate is a moveable muscular structure. It keeps food from entering our nasal cavity when we chew and swallow food.

Uvula

Also known as the “hanging thing”, the function of the uvula is the subject of much debate in the scientific community. Proposed theories include: speech functions, helping fluids go down esophagus, and initiating gag reflex. The uvula may also be linked to snoring and sleep apnea.

Palatine Tonsils

Lymphatic tissue that is connected to either side of the back of the mouth. When people refer to tonsils they are usually talking about the palatines. These tonsils help the immune system and protect against infections of the respiratory system.

Lingual Tonsils

These tonsils are located on the very back of the tongue near the base. These are also lymphatic tissues that help create antibodies to combat pathogens.

Lingual Glands

This is a term for any gland that places substances directly on the tongue’s surface. They are located near the tip of the tongue.

The mouth also contains three types of salivary ducts. Saliva is one of the first materials the body uses to break down food so it can be digested. Saliva is necessary to taste food. It also acts as lubrication when sliding down the esophagus.

Opening and shutting of the mouth seems like a pretty simple process. It is something we take for granted sometimes because we tend not to think too much about an everyday process such as this. However, the process of mastication (chewing food) and opening the mouth would not be possible without these five muscles:

  • Masseter: Closes mouth
  • Temporalis: Closes the mouth and pulls mandible back.
  • Medial Pterygoid: This very large muscle attaches to the side of your head. It also aids in closing the mouth.
  • Lateral Pterygoid: This muscle allows us to push our mandible forward and make side to side movements.

Histology

The mouth is covered in different types of mucous membranes. The type of membrane that covers the mouth is dependant on the area and whether or not it is exposed to abrasive actions such as chewing foods.

In closely examining the mouth we can see three different types of mucosa:

Lining Mucosa

This mucous membrane lines the inside of the lips, bottom of the mouth, bottom of the tongue, and the cheeks. This is classified as stratified squamous nonkeratinized epithelium. Under this mucous membrane is a layer of lamina propria, a thin layer of connective tissue. Salivary glands run into the submucosal regions.

Masticatory Mucosa

This mucosa covers the outside of the lip, the roof of the mouth and the gums. These are stratified keratinized epithelium. This mucosa is more durable and able to deal with the abrasive actions of chewing food. The area that separated the outside lip from the rest of the skin on the face is known as the vermillion border and is only seen in humans.

Specialized Mucosa

Specialized mucosa covers the top and sides of the tongue. This membrane contains specialized nerves that are responsible for sensory and taste reception. The lamina propria that underlies this membrane is thick and connects to the muscle of the tongue. This specialized mucosa contains lingual papillae, or taste buds. The tongue contains four different types of papillae: fungiform, foliate, filiform, and circumvallate.

These membranes are absorbent and allow passage of some materials to go straight into the bloodstream. Some medications such as oral glucose and nitroglycerin tabs must not be ingested because the liver can alter the medication. Therefore they are taken sublingually (below the tongue) or through the buccal membrane (between the cheek and gum).

Functions of the Mouth

Along with getting us into trouble from time to time, our mouths allow us to begin the digestion process by chewing foods and coating it in digestive enzymes from saliva. It also is the main inlet of oxygen when breathing.

The mouth also allows us to express ourselves. Not only does the lips, tongue and teeth help to manipulate air to create words and sounds, but the mouth also creates facial expressions that can convey messages without speaking.

Diseases of the Mouth

The mouth contains as many different types of bacteria as their are people on this planet. It is the middleground between our bodies and the outside world. Because of this, the mouth is can be vulnerable to infections and disorders.

Some common problems of the mouth are:

  • Cold sores: A sore around the lips that can be caused by a type of herpes virus.
  • Canker Sores: Irritating sores that develop inside the mouth. These can be caused by both bacteria or viruses. A canker sore can become a serious problem if left unchecked.
  • Thrush: Common in babies and the elderly, thrush is a yeast infection of the oral cavity.
  • Gingivitis: Inflammation of the gums. Gingivitis results in bleeding gums and is a precursor to periodontal disease.
  • Hand-Foot- Mouth Disease: Caused by the Coxsackievirus, these infection of the mouth can lead to fever, problems eating and fatigue. This is mostly found in children in the late summer and early autumn months.
  • Cancer: Oral cancer is a problem among users of tobacco because of the effects on the mucous membrane. Non tobacco users may also develop oral cancer.

Whether we are eating, breathing, smiling, kissing, or telling a story the mouth plays a huge role in our everyday life. It is key in our ingestion of foods that we need in order to keep going. Taking care of our mouths is as simple as daily brushing and regular physician checkups. Be sure you keep this important area of our anatomy, and social life, healthy.