Science students

1. Salivary glands
By Manali Patil
Roll No – 35

2. Mouth
 Mouth is otherwise known as oral cavity or buccalcavity.
 Digestive juice present in the mouth is saliva
Functions of mouth include:
1. Ingestion of food materials
2. Chewing the food and mixing it with saliva
3. Appreciation of taste of the food
4. Transfer of food (bolus) to the esophagus by swallowing
5. Role in speech
6. Social functions such as smiling and other expres

3. SALIVARY GLANDS
Glands form which saliva is secreted are
called salivary glands
Types
1.Major glands
2.Minor glands

4. Major Glands
1.Parotid glands
2.Submaxillary glands
3.Sublingual glands
Minor Glands
1.Lingual mucus glands
2.Lingual serous glands
3.Buccual glands
4.Labial glands
5.Palatal glands

5. Parotid Gland
Location: At each side of the face ,below and in
front of the ear
Weight: 20 to 30 gm in adults
Duct: Stensen duct
Duct opening: opens inside the cheek against the upper
second molar

6. Submaxillary Gland
Location: submaxillary triangle, medial to mandible
Weight: 8 to 10 gm in adults
Duct: Wharton duct
Duct opening: at the side of frenulum of tongue by a
small opening on a summit of papilla
called caruncula sublingualis.

7. Sublingual glands
Location: situated in the mucosa at the floor of the
mouth
Weight: 2 to 3 gm in adults
Duct: ducts of Rivinus(15-20),Bartholin
duct
Duct opening : open on small papillae beneath the
tongue

8. CLASSIFICATION OF SALIVARY GLANDS
1. Serous Gland
 Serous glands are mainly made up of serous cells which secrete thin and
watery saliva
 Parotid glands and lingual serous glands are the serous glands
2. Mucus Glands
 Mucus glands are mainly made up of mucus cells which secrete thick,
viscous saliva with high mucin content.
 Lingual mucus glands, buccal glands and palatal glands belong to this
type.
3. Mixed Glands
 Mixed glands are made up of both serous and mucus cells.
 Submandibular, sublingual and labial glands are the mixed glands.

9. STRUCTURE AND DUCT SYSTEM
OF SALIVARY GLANDS
Acini or
alveoli
Main duct
Intercalated
duct
Intralobular
duct
Interlobular
duct

10. COMPOSITION OF SALIVA
Saliva contains 99.5% water and 0.5% solids.

11. PROPERTIES OF SALIVA
1.Volume: 1000 mL to 1500 mL saliva is secreted
per day
2. Saliva is slightly acidic with pH of 6.35 to 6.85
3. Specific gravity ranges between 1.002 and 1.012
4. Saliva is hypotonic to plasma.

12. FUNCTIONS OF SALIVA
1. PREPARATION OF FOOD FOR SWALLOWING
 Moistened and masticated food is rolled into a bolus.
 Mucin of saliva lubricates the bolus and facilitates swallowing
2. APPRECIATION OF TASTE
 By its solvent action, saliva dissolves the solid food substances, so
that the dissolved substances can stimulate the taste buds which can
recognize the taste

13. 3. DIGESTIVE FUNCTION
There are three digestive function
Salivary Amylase
It is a carbohydrate-digesting (amylolytic) enzyme .
 Converts starch into dextrin and maltose
 Salivary amylase cannot act on cellulose
Maltase
 Present in traces,converts maltose into glucose.
Lingual Lipase.
Lipid-digesting (lipolytic) enzyme,digests milk fats and hydrolysis
triglycerides into fatty acids and diacylglycerol

14. 4. CLEANSING AND PROTECTIVE FUNCTIONS
 Mucin present in the saliva protects the mouth by lubricating
 Enzyme lysozyme of saliva kills some bacteria such as
staphylococcus, streptococcus and brucella.
 Immunoglobulin IgA in saliva has antibacterial and antiviral
actions.
 Proline-rich proteins and lactoferrin protect the teeth by
stimulating enamel formation.

15. 5.ROLE IN SPEECH
 By moistening and lubricating soft parts of mouth and
lips, saliva helps in speech.
 If the mouth becomes dry, articulation and
pronunciation becomes difficult.
6.EXCRETORY FUNCTION
 Saliva excretes substances like mercury, potassium
iodide, lead, and thiocyanate.
 Excess urea is excreted in saliva during nephritis and
excess calcium is excreted during hyperparathyroidism.

16. 7.REGULATION OF BODY TEMPERATURE
 In dogs and cattle, excessive dripping of saliva
during panting helps in the loss of heat and
regulation of body temperature.
8.REGULATION OF WATER BALANCE
 When the body water content decreases,
salivary secretion also decreases. This causes
dryness of the mouth and induces thirst

17. REGULATION OF SALIVARY SECRETION
Salivary glands are supplied by both parasympathetic
and sympathetic divisions of autonomic nervous system.
Parasympathetic Fibers to Submandibular and Sublingual Glands

18. Parasympathetic Fibers to Parotid Gland

19. Function of Parasympathetic Fibers
 Parasympathetic fibers of salivary glands causes
secretion of saliva with large quantity of water.
 It is because the parasympathetic fibers activate
the acinar cells and dilate the blood vessels of
salivary glands.

20. SYMPATHETIC FIBERS
 Sympathetic preganglionic fibers to salivary glands arise from
the lateral horns of first and second thoracic segments of spinal
cord.
 Postganglionic fibers arise from cervicalganglion and are
distributed to the salivary glands along the nerve plexus, around
the arteries supplying the glands.
Function of Sympathetic Fibers
 Stimulation of sympathetic fibers causes secretion of saliva,
which is thick and rich in organic constituents such

21. APPLIED PHYSIOLOGY
1.HYPOSALIVATION
Reduction in the secretion of saliva is called hypo salivation.
a.Temporary hypo salivation occurs in:
i. Emotional conditions like fear.
ii. Fever.
iii. Dehydration.
b.. Permanent hyposalivation occurs in:
i. Sialolithiasis (obstruction of salivary duct).
ii. Congenital absence or hypoplasia of salivary glands
iii. Bell palsy (paralysis of facial nerve)

22. HYPERSALIVATION
Excess secretion of saliva is known as
hypersalivation.
Conditions:
1.Decay of tooth or neoplasm (abnormal new growth or
tumor) in mouth or tongue due to continuous irritation
irritation of nerve endings in the mouth.
2. Disease of esophagus, stomach and intestine.
3. Neurological disorders such as cerebral palsy, mental
retardation, cerebral stroke and parkinsonism
4. Some psychological and psychiatric conditions.
5. Nausea and vomiting.

23. OTHER DISORDERS:
1.Xerostomia
Xerostomia means dry mouth
i .Trauma to salivary gland or their ducts.
ii.Shock.
iii.Also causes halitosis (bad breath)
2. Drooling
Uncontrolled flow of saliva outside the mouth is called Drooling. It is
often called ptyalism.
i.During teeth eruption in children.
ii. Upper respiratory tract infection or nasal allergies in children
iii. Tonsillitis.

24. 3.Chorda Tympani Syndrome
 Chorda tympani syndrome is the condition characterized by
sweating while eating
4. Paralytic Secretion of Saliva
 When the parasympathetic nerve to salivary glands cut in experimental
animals, salivary secretion increases for first three weeks and later
diminishes; finally it stops at about sixth week.
 The increased secretion of saliva after cutting the parasympathetic
nerve fibers is called paralytic secretion.

25. Augmented Secretion of Saliva
 If the nerves supplying salivary glands are
stimulated twice, the amount of saliva secreted by
the second stimulus is more than the amount
secreted by the first stimulus.
Mumps
 Mumps is the acute viral infection affecting the
parotid glands.
 The virus causing this disease is paramyxovirus,
common in children who are not immunized.
 Features of mumps are puffiness of cheeks (due to
swelling of parotid glands), fever, sore throat and
weakness. Mumps affects meninges, gonads and
pancreas also.

26. Sjögren Syndrome
 An autoimmune disorder in which the immune cells
destroy exocrine glands such as lacrimal glands and
salivary glands.
 Common symptoms are dryness of the mouth,persistent
cough and dryness of eyes.
 In some cases, it causes dryness of skin, nose and
vagina.
 In severe conditions, the organs like kidneys, lungs,
liver, pancreas, thyroid, blood vessels and brain are
affected.