- Saliva: main ingredients
- Daily saliva production
- Regulation of saliva secretion
- Reduced salivation
- Increased salivation
- Role of saliva
- Saliva as a diagnostic material
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Saliva is a clear fluid that is secreted from the salivary glands. You may swallow it nervously, you may miss it in your mouth, and sometimes you may have an excess of it. What is the composition of saliva and what is it for? Check what role it plays in the body.
Saliva(Latinsaliva ) is secreted by the parotid, sublingual and submandibular glands and by small glands located in the oral mucosa. The salivary glands are glands made of vesicles connected by a system of tubes that lead the saliva to the mouth. The pH value of fresh saliva is around 6.6, and its amount is influenced by many factors.
Saliva: main ingredients
- water
- proteins
- enzymes: amylase, lipase, ribonuclease, porotheases
- calcium, fluoride, phosphate, carbonate, sodium, potassium, chloride ions
- mucins, blood group substances, for example A, B, H
Additionally:
- serous effusion
- discharge from the nose and throat
- exfoliated epithelial cells
- leukocytes
- microbes
- leftover food
Daily saliva production
On average, 0.5 to 1 liter of saliva is produced within 24 hours. During sleep, the rate of salivation decreases sharply, and during the day, the salivary glands work most intensively. The greatest salivation occurs just before, during and after a meal. Smell, taste, and even the thought of eating lead to the secretion of more watery saliva.
Saliva production is regulated by the nervous system and the amount depends on gender - men secrete more saliva than women.
Fasting saliva is hypotonic, and when secretion is maximal, it becomes isotonic with the plasma.
As the volume of saliva increases, the content of sodium, calcium and phosphate ions increases. Exercise increases the concentration of sodium
Regulation of saliva secretion
- Saliva is released constantly, even in the absence of external stimuli. The most important things in controlling the work of the salivary glands are: blood pressure
- work of the autonomic nervous system
The autonomic system, especially the parasympathetic part, plays a major role in the production of saliva. After cutting the parasympathetic nerves, the secretory activity of the salivary glands decreases and the glandular tissue disappears after some time.
The secretion of saliva in the mouth under the influence of food is an unconditional reflex. After repeatedly associating unconditional stimuli with neutral ones, the latter may cause the same reaction as unconditional stimuli - salivation.
The salivary glands, like other glands, e.g. digestive glands, are influenced by hormones. Especially pituitary hormones, thyroid hormones and adrenal hormones modify salivation.
Growth hormone, thyroxine, cortisol stimulate the secretion of saliva.
Reduced salivation
Reduced salivation is a phenomenon that occurs in men and women of all ages. It appears:
- dry mouth
- speech impediment
- difficulties with eating dry food
- eating pain
- constantly drinking water
- baking
- difficulties in putting on the prosthesis
The consequences of decreased salivation are mainly tooth decay and infections caused by fungi. Many factors contribute to the reduction of saliva production:
- reduced number of teeth
- weight loss
- some autoimmune diseases, e.g. Sjögren's syndrome
- radiation therapy
- hypertension
- diabetes
- depression
- dehydration
Increased salivation
Drooling is rare. Physiologically, it occurs during tooth eruption, during menstruation, in the first half of pregnancy, or under the influence of a specific smell or mechanical irritation.
Increased salivation may be related to pathological processes. These are mainly:
- toothache
- neurological diseases: Parkinson's disease, epilepsy
- taking poisons
- inflammatory processes in the throat and mouth
Role of saliva
- in protection against caries
Due to the continuous production of saliva, microorganisms and food elements are eliminated from the oral cavity. The main functions of saliva that protect against caries are: antibacterial activity, participation in the demineralization and remineralization of enamel, dissolution and elimination of sugars.
The action of saliva is based on two processes of immune defense: specific defense mechanisms (the presence of immunoglobulins that affect bacterial phagocytosis and slowing down the deposition of tartar) and non-specific defense mechanisms such as the presence of lysozyme, which has the ability to break down the bacterial cell wall.
- environment caching
Teeth are exposed to food ingredients that have a lower pH than saliva, and enamel erosion may occur when ingested. Buffers like bicarbonate come in handy, keeping the concentration of resting saliva between 5.7 and 6.2. When the salivary glands are stimulated, the pH increases due to the increase in the concentration of bicarbonate ions, which protects against caries.
Saliva buffers are involved in neutralizing plaque acids, thereby eliminating bacteria that require a low pH to survive.
- wetting the mouth for articulation, digestion, swallowing
- perception of taste, temperature and touch stimuli
Saliva as a diagnostic material
The main advantages of saliva as a diagnostic material are the availability and non-invasive method of collecting samples for testing
You can determine the risk of caries on the basis of the amount of saliva secreted, its buffering capacity and the content of bacteria Thanks to saliva tests, it is possible to determine the concentrations of: steroid hormones, drugs, addictive substances, alcohol, diagnosis of certain diseases and the use of saliva in forensic medicine.
About the author
Natalia MłyńskaStudent of medicine at the Medical University of Lodz. Medicine is her greatest passion. He also loves sports, mainly running and dancing. She would like to treat her future patients in such a way as to see them as a human being, not only a disease.