The document provides information about salivary glands and saliva. It discusses the anatomy, histology, physiology and functions of saliva. There are three pairs of major salivary glands - the parotid, submandibular and sublingual glands. Saliva is composed of water, electrolytes, enzymes and other proteins. It is produced for lubrication, digestion and protection of teeth and oral cavity. The parotid gland is the largest salivary gland located below and in front of the ear. The submandibular gland is the second largest, located under the jaw bone. The sublingual gland is the smallest, located under the tongue.
INTRODUCTIONSalivary glands are compound tubuloacinar, exocrine gland and the ducts opens in the oral cavity.
Salivary glands secretes a fluid called saliva that coats the teeth and the mucosa.
Saliva is a complex fluid, produced by the salivary glands, the most important function of which is to maintain the well- being of mouth.
Individuals with a deficiency of salivary secretion experience difficulty in eating, speaking, and swallowing and become prone to mucosal infections and dental caries.
INTRODUCTION
DEFINITION
EMBRYOLOGY/DEVEOLPMENT
HISTOLOGY OF SALIVARY GLANDS
CLASSIFICATION OF SALIVARY GALNDS
ANATOMY OF SALIVARY GLANDS
AGE CHANGES
CLINICAL CONSIDERATION
CONCLUSION
Muscles of mastication are the group of muscles that help in movement of the mandible as during chewing and speech. We need to study these muscles as they control the opening & closing the mouth & their role in the equilibrium created within the mouth. They also play a role in the configuration of face.
PHYSICAL PROPERTIES
CHEMICAL PROPERTIES
STRUCTURE OF ENAMEL
DEVELOPMENT OF ENAMEL
EPITHELIAL ENAMEL ORGAN
AMELOGENESIS
LIFE CYCLE OF AMELOBLASTS
AGE CHANGES IN ENAMEL
DEFECTS OF AMELOGENESIS
CLINICAL IMPLICATIONS
INTRODUCTIONSalivary glands are compound tubuloacinar, exocrine gland and the ducts opens in the oral cavity.
Salivary glands secretes a fluid called saliva that coats the teeth and the mucosa.
Saliva is a complex fluid, produced by the salivary glands, the most important function of which is to maintain the well- being of mouth.
Individuals with a deficiency of salivary secretion experience difficulty in eating, speaking, and swallowing and become prone to mucosal infections and dental caries.
INTRODUCTION
DEFINITION
EMBRYOLOGY/DEVEOLPMENT
HISTOLOGY OF SALIVARY GLANDS
CLASSIFICATION OF SALIVARY GALNDS
ANATOMY OF SALIVARY GLANDS
AGE CHANGES
CLINICAL CONSIDERATION
CONCLUSION
Muscles of mastication are the group of muscles that help in movement of the mandible as during chewing and speech. We need to study these muscles as they control the opening & closing the mouth & their role in the equilibrium created within the mouth. They also play a role in the configuration of face.
PHYSICAL PROPERTIES
CHEMICAL PROPERTIES
STRUCTURE OF ENAMEL
DEVELOPMENT OF ENAMEL
EPITHELIAL ENAMEL ORGAN
AMELOGENESIS
LIFE CYCLE OF AMELOBLASTS
AGE CHANGES IN ENAMEL
DEFECTS OF AMELOGENESIS
CLINICAL IMPLICATIONS
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CONTENT
INTRODUCTION
DEVELOPMENT
PAROTID CAPSULE
EXTERNAL FEATURES
RELATIONS
STRUCTURE WITHIN THE PAROTID GLAND
PAROTID DUCT
NERVE SUPPLY
LYMPHATIC DRAINAGE AND LYMPH NODES
FUNCTIONS OF PAROTID GLAND
ROLE OF PUBLIC HEALTH DENTIST
CONCLUSION
REFERENCES
Dr. Ahmed M. Adawy
Professor Emeritus, Dep. Oral & Maxillofacial Surg.
Former Dean, Faculty of Dental Medicine
Al-Azhar University
Salivary glands are exocrine glands that produce saliva through a series of ducts. The glands may be affected by a wide range of disorders. They can be involved with acute and chronic inflammatory processes, give rise to benign and malignant tumors, manifest congenital abnormalities or represent involvement of a systemic disorder. Further, partial or complete obstruction of the ductal element can occurs. Physical examination and diagnostic aids are presented. Current surgical managements of these disorders are discussed.
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ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
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This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
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Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
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3. INTRODUCTION
The oral cavity is a moist environment, a film of
fluid called saliva constantly coats its inner
surfaces and occupies the space between the
lining oral mucosa and the teeth.
Saliva is a complex fluid, produced by the
salivary glands, whose important role is
maintaining the wellbeing of the mouth.
Patients with a deficiency of salivary secretion
experience difficulty eating, speaking,
swallowing as well as become prone to mucosal
infections and rampant caries.
5. ANATOMY
There are three pairs of major salivary
glands.
1. Parotid glands
2. Submandibular glands
3. Sublingual glands.
There are more than 400 minor salivary
glands (labial, lingual, palatal, buccal,
glossopalatine and retromolar).
6. Parotid gland
FEATURES=>
Para-around ; otic-ear
It is the largest salivary gland
It wieghs about 15 gm
Situated below the external acoustic meatus,
between the ramus of the mandible and
sternocliedomastoid.
A part of this forward extension deattched and
known as accessory parotid and it lies between
the zygomatic arch and the parotid duct.
7. Capsule of the parotid gland
Investing layer of the deep cervical fascia
forms capsule for the gland.
Fascia splits to enclose the gland.
The superficial lamina is thick and adherent
to the gland and attached above to the
zygomatic arch.
The deep lamina is thin and is attached to
the styloid process, the angle and the
posterior border of the ramus of the
mandible and the tympanic plate.
8. A portion of deep lamina extending between
the styloid process and the mandible is
thickened to form the stylomandibular
ligamnet which separates the parotid gland
from the submandibular salivary gland.
The ligament is pierced by the external
carotid artery.
9. External features
The gland resembles three sided pyramid.
Apex of pyramid is directed downwards .
The gland has four surfaces:-
Superior(base of pyramid)
Superficial
Anteriomedial
posteromedial
10. The surfaces are separated by three
borders:
Anterior
Posterior
Medial/pharyngeal
16. Parotid duct/ stenson’s duct
It is thick walled and about 5 cm long.
It emerges from the middle of the anterior
border of the gland.
It runs forward and slightly downwards on
the masseter.
17. Stenson’s duct relations are:-
Superiorly:-
Accesory parotid gland
Transverse facial vessels
Upper buccal branch of the facial nerve
Inferiorly
Buccal fat pad
Buccopharyngeal fascia
Buccinator (obliuquely)
18. Blood supply:
Arterial:
o External carotid artery
o Its terminal branches
o Posterior auricular
o Superficial temporal
o Transverse facial arteries
Venous:
Retromandibular vein
20. Autonomic nerve innervation
1. Parasympathetic secretomotor fibers from the
inferior salivatory nucleus of the ninth cranial
nerve supply the parotid gland. The nerve fibers
pass to the otic ganglion via the tympanic branch of
the ninth cranial nerve and the lesser petrosal
nerve.
2. Postganglionic parasympathetic fibers reach the
parotid gland via the auriculotemporal nerve,
which lies in contact with the deep surface of the
gland.
23. Sympathetic nerves are vasomotor and are
derived from the plexus around the middle
meningeal artery.
Sensory nerves to the gland come from the
auriculotemporal nerve, but the parotid
fascia is innervated by the great auricular
nerve (C2, C3).
24. Applied aspects
Parotid swellings are very painful due to the
underlying nature of the parotid fascia.
The lobule of the ear is often pushed up in
parotid swelling
Mumps is infection of salivary gland caused
by paromyxovirus which will cause severe
pain
25. A parotid abscess may be caused by the
spread of infection from the oral cavity.
An infection may also spread due to the
parotid lymph node draining an infected
area.
For tumours of the parotid gland incision
biopsy is not indicated as it will cause the
seeding of the tumour .
26. Parotidectomy is the removal of the parotid
gland. After this operation at times there may
be regeneration of the secretomotor fibres in
the auriculotemporal nerve which join the
great auricular nerve.
This causes stimulation of the sweat glands
and hyperaemia in the area of its distribution
thus producing redness and sweating in the
area of skin supplied by the nerve.
27. This clinical entity is called FREY
SYNDROME.
Whenever such a person chew there is increase
in the sweating in the region supplied by
auriculotemporal nerve.
So it is called auriculotemporal syndrome
28. Submandibular salivary gland
Second largest salivary
gland
Situated in the anterior
part of the the
diagastric traingle
Gland is size of walnut
It is roughly J-shaped
29. Superficial part
Inferior surfaces
Lateral surface
Medial surfaces
The gland is enclosed to
between two layers of
deep cervical fascia.
30. Relations
Inferior surface is covered by:-
Skin
Platysma
Cervical branch of the facial nerve
Deep fascia
Facial vein
Submandibular lymph nodes
31. Lateral surface related to:-
Submandibular fossa related to the mandible
Insertion of the medial pterygoid
Facial artery
32. Medial surface related
to the:-
Mylohyoid
Hyoglossus
Styloglossus muscle
Inferiorly : it overlaps stylohyoid and the
posterior belly of the diagastric.
33. Deeper part
Small in size
Situated deep to the mylohyoid
line and superficial to the
hyoglossus and styloglossus
Posteriorly, it is continuous with
the superficial part round the
posterior border of the
mylohyoid.
Anteriorly, it extends up to the
posterior end of the sublingual
gland
34. Relations
Present in between mylohyoid and
hyoglossus
Laterally- Mylohyoid
Medially- Hyoglossus
Above – lingual nerve with sub mandibular
ganglion
Below – Hypoglossal nerve
36. Submandibular duct / wharton’s
duct
Thin walled and is about 5 cm long.
Emerges from the anterior end of the deeper part
of the gland.
Runs forward to the hyoglossus between the
lingual and hypoglossal nerves.
At the anterior border of the hyoglossus, duct is
crossed by the lingual nerve.
Opens in the floor of the mouth on the summit of
sublingual papilla, at the side of the frenulum of
the tongue.
40. Vasomotor sympathetis- fibres from the
plexus on the facial artery.
Sensory fibres - Lingual nerve.
41. Applied aspects
The formation of calculus is more common in
the submandibular gland than in the parotid.
A stone in the submandibular duct(wharton’s
duct) can be palpated bimanually in the floor of
the mouth and can even be seen if sufficiently
large.
43. Lies above the mylohyoid below the mucosa of
the floor of the mouth, medial to sublingual fossa
of the mandible and lateral to the genioglossus.
44. Relations
Front- meet with the opposite side gland
Behind – comes in contact with the deeper
part of the submandibular gland
Above- mucous membrane of the mouth
Below- mylohyoid muscle
Lateral- sublingual fossa
Medial- genioglossus muscle
45. Sublingual gland has no true fascial capsule.
It lacks a single dominant duct. Instead, it is
drained by approximately 10 - 12 small ducts
(the Ducts of Rivinus).
Ducts of Rivinius either secrete directly into
floor of mouth or empty into BARTHOLIN’s
duct that then continues into Wharton’s duct.
The gland receives blood supply from the
lingual and submental arteries.
Nerve supply is similar to that of
submandibular gland
46. Applied aspects
The structures at risk during dissection of
the gland are the submandibular duct and the
lingual nerve.
The duct lies superficially in the floor of the
mouth medial to the sublingual fold, and is
crossed inferiorly by the nerve which then
enters the tongue
The sublingual artery and vein also lie on
the medial aspect of the gland close to the
submandibular duct and lingual nerve.
47. Minor salivary glands
About 600 to 1,000 minor salivary glands,
ranging in size from 1 to 5 mm, line the oral
cavity and oropharynx.
These lie just under mucosa.
Distributed over lips, cheeks, palate, floor of
mouth & retro-molar area.
Also appear in upper aero-digestive tract
Contribute 10% of total salivary volume.
49. The salivary glands develop as outgrowth of
the buccal epithelium.
The outgrowths are at first solid and are later
canalised.
They branch repeatedly to form the duct
system.
The terminal parts of the duct system develop
into secretory acini.
50. As the salivary glands develop near the
junctional area between the ectoderm of the
foregut, it is difficult to determine whether they
are ectodermal or endodermal.
The outgrowth for the parotid gland arises in
relation to the line along which the maxillary
and mandibular process fuse to form the cheek.
it is generally cosidered as ectodermal.
51. The outgrowths for the submandibular and
sublingual glands arise in relation to the linguo-
gingival sulcus. They are usually cosidered to
be of endodermal origin.
54. Structure of salivary glands
The working parts of the
salivary glandular tissue consist
of the secretory end pieces
(acini) and the branched ductal
system.
In serous glands (e.g. the
parotids) the cells in the end
piece are arranged in a roughly
spherical form.
In mucous glands, they tend to
be arranged in a tubular
configuration with a larger
central lumen.
55. In both types of gland the cells
in the end piece surround a
lumen and this is the start of
the ductal system.
There are three types of duct
present in all salivary glands.
Intercalated duct
Striated duct
Excretory duct
56. The fluid first passes through the
intercalated ducts which have low
cuboidal epithelium and a narrow
lumen.
From there the secretions enter the
striated ducts which are lined by
more columnar cells with many
mitochondria.
Finally, the saliva passes through the
excretory ducts where the cell type is
cuboidal until the terminal part which
is lined with stratified squamous
epithelium.
57. End pieces may contain mucous cells, serous
cells or a mixture of both.
A salivary gland can consist of a varied mixture
of these types of end pieces.
In mixed glands, the mucous acini are capped by
a serous demilune.
In addition, myoepithelial cells surround the end
piece, their function being to assist in propelling
the secretion into the ductal system.
The gland and its specialised nerve and blood
supply are supported by a connective tissue
stroma.
58. Differences:-
Serous acini Mucous acini
1. Samller in size,rounded in
shape.
2. Lumen hardly visible.
3. Lining cells pyramidal in
shape and relatively more in
number.
4. Nuclie are round and basal.
5. Cytoplasm depicts basal
basophilia and apical
eosinophilia.
6. May present as demilunes on
one aspect of some mucous
acini
1. Larger in size , more variable
in shape.
2. Lumen mostly visible.
3. Lining cells truncated
columnar in shape. Cells
relatively fewer in number.
4. Nuclie are flattened and
peripheral.
5. Cytoplasm is pale and
vacuolated.
6. Mucous acini only present as
complete acini.
63. Physiology of saliva
Composition-
Saliva is slightly cloud in appearance due to the
presence of cells and mucin.
Saliva is slightly acidic and the Ph varies from
6.7 to 7.4, specific gravity is 1.002 to 1.012.
The resting rate of saliva is on an average is
about 0.3 to 0.4 ml/min..
Saliva contains about 99.5% of water and 0.5%
of solid.
64. Solid present in saliva consists:-
Cellular costituents – consist of yeast, bacteria,
protozoa, polymorphonuclear leukocytes and
desquamated epithelial cells.
Inorganic ions- major(Na + ,k+ ,Cl-,HCO3-) and
Minor (Ca++ ,Mg++ ,HPO4-, I, Scn- and F-)
65. Secretory proteins and glycoprotiens – various
enzymes, large carbohydrte rich protien or
mucin, antibacterial substance, group of
protiens involved in enamel.
Serum constituents- albumin, blood clotting
factor , B2 microglobulin and immunoglobulin.
66.
67. Source of saliva-
Saliva is secreted from the salivary glands: via
parotid gland-25%; submandibular gland –
70% ; sublingual gland – 5%
Minor salivary gland present on palate , buccal
mucosa, and tongue also produce modest
amounts of saliva.
68. Normal stimulated flow of saliva- for different
ages can be calculated by the equation:-
0.78 * age + 5.6 = stimulated flow / 15 min
5.6 – it is stimulated flow of the infants
69. Secretion of saliva
Although fluid secretion occurs only through the
acini, proteins are produced and transported into
the saliva through both acinar and ductal cells.
The primary saliva within the acinar end pieces
is isotonic with serum but undergoes extensive
resorption of sodium and chloride and secretion
of potassium within the duct system.
The saliva, as it enters the oral cavity, is a
protein-rich hypotonic fluid.
70. The secretion of saliva is controlled by
sympathetic and parasympathetic neural input.
The stimulus for fluid secretion is primarily via
muscarinic-cholinergic receptors, whereas the
stimulus for protein release occurs largely
through b-adrenergic receptors. Salivary cells
also display an array of additional receptors that
influence secretory functions.
71. Activation of these receptors induces a
complex signaling and signal transduction
pathway within the cells, involving numerous
transport systems, resulting in a tightly
regulated secretion process.
Mobilization and regulation of intracellular
calcium are a critical component of this process
within the secretory cells.
72. Nervous Regulation of Salivary
Secretion
The salivary glands are controlled mainly by
the parasympathetic nervous signals all the way
from the superior and inferior salivatory nuclei
in the brain stem.
The salivatory nucleus located at the juncture
of the medulla and pons and are excited by
both taste and tactile stimuli from the tongue
and other areas of the mouth and pharynx.
73. Sour taste stimuli elict the saliva secretion 8 to 20
times than the basal rate.
Salivation can also be stimulated or inhibited by
nervous signals arriving in the salivatory nuclei
from higher centres of the central nervous
system.
The appetite area of the brain , which partially
regulates secretion is located in proximity to the
parasympathetic centres of the hypothalmus, and
it function to great extent in response to signals
from the taste and smell area of cerebral cortex or
amygdala.
74. Sympathetic stimulation can also increase the
salivation a slight amount, much less so than
does parasympathetic stimulation. The
sympathetic nerves originate from the superior
cervical ganglia and travel along the surfaces of
the blood vessels walls of the salivary glands.
75.
76. Functions of saliva
Function Action
Fluid/Lubricant Coats hard and soft tissue which helps to protect against
mechanical, thermal and chemical irritation and tooth wear.
Assists smooth air flow, speech and swallowing.
Ion reservoir Solution supersaturated with respect to tooth mineral facilitates
remineralisation of the teeth. Statherin and acidic proline-rich
proteins in saliva inhibit spontaneous precipitation of calcium
phosphate salts.
Buffer Helps to neutralise plaque pH after eating, thus reducing time for
demineralisation.
Cleansing Clears food and aids swallowing.
Antimicrobial
actions
Specific (e.g. sIgA) and non-specific (e.g. Lysozyme,Lactoferrin
and Myeloperoxidase) anti-microbial mechanisms help to control
the oral microflora.
Agglutination Agglutinins in saliva aggregate bacteria, resulting in accelerated
clearance of bacterial cells. Examples are mucins and parotid
saliva glycoproteins.
77. Pellicle formation Thin (0.5 μm) protective diffusion barrier formed on
enamel from salivary and other proteins.
Digestion The enzyme α-amylase is the most abundant salivary
enzyme; it splits starchy foods into maltose, malto-triose
and dextrins.
Taste Saliva acts as a solvent, thus allowing interaction of
foodstuff with taste buds to facilitate taste
Excretion As the oral cavity is technically outside the body,
substances which are secreted in saliva are excreted.
This is a very inefficient excretory pathway as
reabsorption may occur further down the intestinal tract.
Water balance Under conditions of dehydration, salivary flow is
reduced, dryness of the mouth and information from
osmo-receptors are translated into decreased urine
production and increased drinking.
78. „APPLIED PHYSIOLOGY
HYPOSALIVATION
Reduction in the secretion of saliva is called
hyposalivation.
It is of two types, namely temporary
hyposalivation and permanent hyposalivation.
1. Temporary hyposalivation occurs in:
i. Emotional conditions like fear.
ii. Fever.
iii. Dehydration.
79. 2. 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).
80. HYPERSALIVATION
Excess secretion of saliva is known as
hypersalivation.
Physiological condition when hypersalivation
occurs is pregnancy. Hypersalivation in
pathological conditions is called ptyalism,
sialorrhea, sialism or sialosis.
81. Hypersalivation occurs in the following
pathological conditions:
1. Decay of tooth or neoplasm (abnormal new
growth or tumor) in mouth or tongue due to
continuous irritation of nerve endings in the
mouth.
2. Disease of esophagus, stomach and intestine.
82. 3.Neurological disorders such as cerebral palsy,
mental retardation, cerebral stroke and
parkinsonism.
4.Some psychological and psychiatric conditions.
5.Nausea and vomiting.
83. OTHER DISORDERS
1. Xerostomia
2. Drooling
3. Chorda tympani syndrome
4. Paralytic secretion of saliva
5. Augmented secretion of saliva
6. Mumps
7. Sjögren syndrome.
84. 1. Xerostomia
Xerostomia means dry mouth. It is also called
pasties or cottonmouth. It is due to
hyposalivation or absence of salivary secretion
(aptyalism).
Causes-
i. Dehydration or renal failure.
ii. Sjögren syndrome.
iii. Radiotherapy.
iv. Trauma to salivary gland or their ducts.
85. v. Side effect of some drugs like antihistamines,
antidepressants, monoamine oxidase inhibitors,
antiparkinsonian drugs and antimuscarinic drugs.
vi. Shock.
vii. After smoking marijuana (psychoactive
compound from the plant Cannabis).
Xerostomia causes difficulties in mastication,
swallowing and speech. It also causes halitosis (bad
breath; exhalation of unpleasant odors).
86. 2. Drooling
Uncontrolled flow of saliva outside the mouth is
called drooling. It is often called ptyalism.
Causes-
Drooling occurs because of excess production of
saliva, in association with inability to retain saliva
within the mouth.
87. Drooling occurs in the following conditions:
i. During teeth eruption in children.
ii. Upper respiratory tract infection or nasal
allergies in children.
iii. Difficulty in swallowing.
iv. Tonsillitis.
v. Peritonsillar abscess.
88. 3. Chorda Tympani Syndrome
Chorda tympani syndrome is the condition
characterized by sweating while eating.
During trauma or surgical procedure, some of the
parasympathetic nerve fibers to salivary glands
may be severed.
During the regeneration, some of these nerve
fibers, which run along with chorda tympani branch
of facial nerve may deviate and join with the nerve
fibers supplying sweat glands.
When the food is placed in the mouth, salivary
secretion is associated with sweat secretion.
89. 4. Paralytic Secretion of Saliva
When the parasympathetic nerve to salivary
gland is 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. It is because of hyperactivity of
sympathetic nerve fibers to salivary glands after
cutting the parasympathetic fibers.
90. These hyperactive sympathetic fibers release
large amount of catecholamines, which induce
paralytic secretion.
Moreover, the acinar cells of the salivary glands
become hypersensitive to catecholamines after
denervation.
The paralytic secretion does not occur after the
sympathetic nerve fibers to salivary glands are
cut.
91. 5. 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.
It is because, the first stimulus increases
excitability of acinar cells, so that when the second
stimulus is applied, the salivary secretion is
augmented.
92. 6. Mumps
Mumps is the acute viral infection affecting the
parotid glands.
The virus causing this disease is Paramyxovirus.
It is common in children who are not immunized.
It occurs in adults also.
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.
93. 7. Sjögren Syndrome
Sjögren syndrome is an autoimmune disorder in
which the immune cells destroy exocrine glands
such as lacrimal glands and salivary glands.
It is named after Henrik Sjögren who discovered
it. Common symptoms of this syndrome are
dryness of the mouth due to lack of saliva
(xerostomia), persistent cough and dryness of
eyes.
94. 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.
95. References
Human Anatomy volume 3 – B D Chaurasia’s
Text book of Oral Medicine – Anil Govindrao Ghom
Essential of Medical Physiology sixth edition – K
Sembulingam , Prema Sembulingam
Text book of Medical Physiology eleventh edition- Guyton
& Hall
Text book of Histology third edition – Krishna Garg, Indira
Bahl, Mohini Kaul
Introduction: the anatomy and physiology of salivary
glands - Helen Whelton