Salivary glands and its applied Dr Pushpa Lata

Salivary glands and its’ applied -Dr Pushpa Lata Sachan Associate Prof. Dept. Physiology CIMS & H

These are compound tubuloacinar exocrine glands found in oral cavity that secrete complex fluid known as saliva. CLASSIFICATION OF SALIVARY GLANDS – 1 -Based on size 2 -Based on type of secretory cells

CLASSIFICATION OF SALIVARY GLANDS BASED ON SIZE: 1. Major salivary glands 1. Parotid, 2. Submandibular and 3. Sublingual. 2. Minor salivary glands- Lingual, buccal, labial, palatal glands, glossopalatine and retromolar glands.

CLASSIFICATION OF SALIVARY GLANDS Based on type of secretory cells 1. Serous - Parotid 2. Mixed (seromucous)- Submandibular 3. Mucous- Minor salivary glands.

Composition of salivary Juice: �Daily secretion : - 1000 ml to 1500 ml �PH: - slightly below 7 (6. 35 to 6. 85)- slightly acidic � 99. 5% water � 0. 5% solids: � � � (a)Inorganic sub stances: Na+, k+, Ca+, Hco 3, Cl, So 4, Po 4, etc. (b) Organic- sub stances: -

(b) Organic- substances: �Salivary protein – mucin (glycoprotein) �Enzymes: �Ptyalin, or , salivary- amylase (main Enzyme) �Lingual lipase �Lysozymes (bactericidal) �Blood group antigens. �Ig. A (for defence against bacteria & viruses )

�Enzymes: α- amylase Lysozyme, Lactoperoxidase, Kallikrein, Mucins Lactoferrin and many others. �Immunoglobulins. � Ptylin is an enzyme for digesting starch. �Mucin for lubricating and for surface protective purposes.

Parotid gland �Parotid gland -Largest salivary gland 25% of total saliva. �Stenson’s duct: - runs forward across masseter muscle, turns inwards at the anterior border of masseter and opens at a papilla in the oral cavity just opposite second molar crown. �By stenson’s duct parotid gland secretions reaches to oral cavity.

Submandibular glands �Almost 75% of total saliva secretions by this glands. �Wharton's duct runs forward and opens into the mouth beneath the tongue, lateral to lingual frenum. �Serous secretion -That contains Ptylin. �Parotid glands secrete almost entirely serous type of secretion while submandibular and sublingual glands secrete both serous secretion and mucus. �Buccal glands secrete only mucus.

Functions of Saliva �Oral hygiene � saliva helps prevent the deteriorative processes in several ways. �Protective function-saliva contains lysozyme, which is anti-bacterial. �Ig. A in saliva provides local immunity and lactoferrin in saliva is bacteriostatic. �Saliva keeps the mouth cavity and tongue moist which facilitates speech. �Saliva increases the taste of food �Saliva helps in mastication and swallowing.

�In the absence of saliva , deglutition becomes impossible. �Saliva contain bicarbonate which buffers gastric acid in this way reduces heart burn. �Proline rich protein in saliva protects enamel of teeth and thus provides them strength. �Proline also binds with tannin and reduces the toxicity. �Saliva prevents the injury to buccal mucosa by diluting the hot and irritant food materials.

REGULATION OF SALIVARY SECRETION: �Two varieties of salivary secretion: �SPONTANEOUS SECRETION : - Occurs all the time , without any known stimulus, & -keeps the mouth – moist all the time

� STIMULATED SECRETION: - Occurs After a known stimulus, e. g. �Psychological (thinking of food / sweet) �Visual (looking at delicious food / sweet) �Taste (tasting good food , in the mouth) �Others (if during vomiting) �Stimulated secretion of saliva – is due to reflex salivary reflex – which depends on nerves, supplying salivary glands.

NERVE – SUPPLY TO SALIVARY GLANDS: (a)Para sympathetic N. supply: (i) Parotid S. G. - by ix- N. (Gloss pharyngeal) (ii) sub mandibular & sublingual S. G. – by VII- N. (facial) �Stimulation of sympathetic nervous system – decreases secretions of saliva.

Para Sympathetic – Innervation To Salivary Glands �So, VII-cranial nerve – supplies: - Sub mandibles & Sublingual salivary gland. �& IX Cranial Nerve- Supplies: - Parotid –salivary gland. �Para sympathetic stimulation – increases salivary glands secretion.

Salivary Reflexes Two types of Salivary Reflexes: �UNCONDITIONED – REFLEX : - are in born & present since birth. �Their presence require – no previous experience �E. g. salivary secretion in oral phase �CONDITIONED – REFLEX: - require previous – experience, or training , -are not inborn �e. g. salivary secretion in Cephalic – phase �The reflex was discovered by – Ivan – Pavlov

Mechanism of Salivary Reflex: �(a) -Stimulus (food / sweet) in Cephalic , or oral – Phase �(b) Afferent- limb - reaches to � (c) salivary center (In medulla & lower part of Pons), Nucleus tractus Solitarius To Superior & Inferior Salivary nucleus �(d) Efferent limb – Para sympathetic nerves (VII & IX - N. ) �(e) Salivary glands �(f) Salivary secretion.

APPLIED – ASPECTS: �HYPO SALIVATION : - Decreased salivary secretion �Absence of or deficiency in secretion of saliva -known as -“Aptyalism” – resulting in “xerostomia” or” Dry mouth

�Causes of temporary – hypo salivation: �Dehydration - (e. g. Diarrhoea , Excessive Sweating , etc. ) �Fever �Emotional Conditions like fear, depression etc. �Shock �After Smoking �By some drugs – Avil, Atropine, etc.

Causes of Permanent- Hypo salivation: �“Sialolithiasis”-i. e. obstruction of salivary duct by stone. �Congenital absence , or , hyperplasia of salivary gland – Atyalism. �‘Bell’s – palsy ‘ i. e. paralysis of facial nerve. � Irradiation therapy- in area of salivary glands. �

Hyper salivation � HYPER SALIVATION: - Excess secretion of saliva. �In following Conditions: �Physiological Conditions : �e. g. Pregnancy

HYPER SALIVATION � (b) Pathological Condition: - Also called “Ptyalism ” or Sialorrhea ‘ �e. g. Dental Caries , tooth decay , oral tumor �Disorders of esophagus , stomach & intestine �Nausea & vomiting �Neurological disorders, � e. g. – Cerebral palsy � - Mental retardation � - Cerebral stroke � - parkinsonism