Anatomy and physiology of salivary glands

Dr. Supreet Singh Nayyar, AFMC

For more topics, visit www.nayyarENT.com

 Anatomy of Parotid, Submandibular, Sublingual
glands

 Physiology – structure of glands, secretion of
primary fluid, neuronal
control, neurotransmitters

 Factors affecting salivary flow & composition

www.nayyarENT.com 7/13/2012 2

 3 Pairs – Major
salivary glands

 Parotid
 Submandibular
 Sublingual

 Collection of salivary
tissue within oral
mucosa – Minor
salivary glands


 Ectoderm of oral cavity

 Solid bulb from oropharyngeal epithelium
 6 weeks - parotid gland

 Dichotomous branching of solid bulb,
development of lumen, condensation of
mesenchyme

 Formation of primitive ducts


 Engulfment of facial nerve – 16th- 21st wk

 Functional maturation after feeding is
established


 Lobulated, “inverted
pyramid”, extent

 Superficial, deep lobes

 Parotid space

 Borders - ant, post

 Surfaces – superficial,
superior, anteromedial,
posteromedial


 Condensed deep cervical fascia, tough,
inelastic surface component, thin deep layer

 Stylomandibular ligament

 Fibrous septa arise from capsule

 Contents of fascia – superficial lymph nodes,
greater auricular nerve


• Facial nerve,
division of gland

• Retromandibular
vein, anterior and
posterior divisions

• External carotid
artery, terminal
branches


 Capsule – Periparotid Nodes

 Mostly superficial to Facial Nerve

 Part of MALT, secrete IgA

 Salivary gland tissue may be present within the
lymph nodes


 Stylomastoid foramen

 Methods of identification
during surgery

 TM Sulcus
 PBD
 Tragal pointer
 Mastoid
 Retrograde
 Styloid process


 Varied, Surgically
important

 Single trunk, divides into
Zygomaticotemporal,
Cervicomandibular

 Temporal, upper / lower
zygomatic, buccal

 Buccal, cervical,
mandibular


 Type1-5 ( Katz and Catalano, 1987)
 Type 1 (25%) – No anastomotic links
 Type 2 (14%) – Buccal fuses distally with Zygomatic
 Type 3 (44%) – Major communication between Buccal &
others
 Type 4 (14%) – Anastomosis between major divisions
 Type 5 (3%) – More than one Facial Nv trunk

 Unpredictable preoperatively, to be precisely
defined during surgery


Parasympathetic Sympathetic
Inferior salivatory nucleus Superior cervical ganglion

IX nerve
Plexus around ECA
Lesser Petrosal nerve
PAROTID
Otic ganglion

Auriculotemporal nerve

PAROTID


 Formed near the anterior
border

 Lies on superficial
surface of Masseter

 Opens in the mouth at
parotid papilla

 Accessory Parotid tissue


 Development
 6th IU wk
 Ectoderm in floor of primitive oral cavity
 Lateral to primitive tongue
 Development of acini – 12th wk

 Large superficial, small deep lobe
 Located in Submandibular triangle
 Well defined capsule


 Superficial Lobe

 Inferior surface –
Digastric, Deep fascia,
Platysma, Skin

 Lateral surface –
Submandibular fossa,  Medial surface – Mylohyoid,
Facial artery Hyoglossus, Lingual nerve, XII
nv, Submandibular ganglion,
Deep lingual vein


 Extends for a variable distance between
Mylohyoid & Hyoglossus

 Relations
 Superior – Lingual nerve
 Inferior – XII Nv, Deep lingual vein, Submandibular duct


 5 cm in length
 Middle of deep part
 Crosses Sublingual space
 Proximally – b/w Mylohyoid & Hyoglossus
 Distally – b/w Genioglossus & Sublingual gland
 Opening – on sides of frenulum of tongue
 Relation to Lingual nerve


 Branches of Facial & Lingual arteries

 Lymph nodes adjacent to the superficial part


 Parasympathetic  Sympathetic
Superior Salivary Nucleus Superior Cervical Ganglion

Nervus Intermedius
Plexus around Facial Artery
Facial Nerve

Chorda Tympani Submandibular Ganglion

Lingual Nerve
SUBMANDIBULAR GLAND
Submandibular Ganglion


 Skin incision – 4 cm below Mandible

 Ligation of Facial vessels above & below

 Dissected away from Lingual Nerve

 Lymph nodes in substance of gland


 Development
 8th wk
 Epithelial buds present
in paralingual sulcus

 Almond shaped

 Located in anterior
part of floor of
mouth


 Sup – Oral floor mucosa

 Inf – Mylohyoid

 Post – Deep part
Submandibular gland

 Med – Lingual
nerve, Submandibular
duct, Genioglossus

 Lat– Med surface of lower
Mandible


 Ducts
 Multiple
 Drain into oral cavity directly or into Submandibular
duct

 Blood supply

 Nerve supply


 Produce saliva – 1L / day (1ml/min/gm)

 Contents
 Mucin (glycoprotein)
 Salivary amylase
 Secretory Immunoglobulins
 Other enzymes –
DNase, RNase, lysozyme, lactoperoxidase, lingual lipase
 Kallikerin
 Inorganic compounds – Na+, K+, HCO3-, Ca2+


 Lubrication and protection

 Buffering and clearance

 Maintenance of tooth integrity

 Antibacterial activity

 Taste and digestion


 Parotid
 Largest, serous (Compound Tubuloacinar Gland)

 Submandibular and Sublingual
 Mixed (Compound Tubuloacinar Glands)


 Serous Acini
◦ Pyramid shaped, basal
nucleus, apical
secretory granules
 Mucus Acini
◦ Larger, columnar cells,
basal nucleus
 Mixed Acini
◦ Mucus acini capped by
serous cells forming
Serous Demilunes


Acini

Intercalated Ducts

Striated Ducts

Interlobular Excretory Ducts

Stenson’s, Wharton’s duct


 High rates

 Rate of saliva production – 1ml/min/gm

 Blood flow 10 times that of equal mass of
skeletal muscle


 Active transport process under neuronal
control

 Composition
 Hypotonic to plasma
 Tonicity more when rates of production are high( at
max rate - 70% to that of plasma)
 K+,HCO3- higher than in plasma
 pH – acidic during resting phase, basic during active
phase(↑ HCO3- secretion)


 Acini – Primary Fluid Secretion
 Isotonic to plasma, electrolyte composition fairly
constant, exocrine protein

 Excretory ducts – extract Na+, Cl- and add
K+, HCO3- to saliva
 No addition in volume
 More of Na+, Cl- removed than addition of K+, HCO3-
responsible for hypotonicity


 Osmotic process
 Transepithelial salt gradients

 Four ion transport systems - luminal and basolateral
membranes generate the gradient

 Three mechanisms proposed – operate concurrently


 Stimulation – rise in cytosolic
Ca2+

 Opening of K+, Cl- channels –
KCl outflow

 Cl- conc in lumen ↑, Na+,
H2O follow

 Cl- entry sustained via
Na+K+2Cl- cotransporter

 6 Cl- translocated to acinar
lumen per ATP hydrolysed by
Na+/K+ ATPase


 Cl-/HCO3-, Na+/H+ exchanger

 KCl outflow

 Cl- entry via Cl-/HCO3-
exchanger

 Acidification buffered by
Na+/H+ exchanger

 3 Cl- translocated to lumen per
ATP hydrolysed

 Na+ & water follow into the
lumen


 Involves acinar HCO3-
secretion

 3 HCO3- secreted per ATP
molecule

 H+ extruded via Na+/H-
exchanger

 Na+, H2O follow into the
lumen


 Contained in zymogen granules present in
serous acinar cells, ductal cells

 Upon stimulation release contents in lumen by
exocytosis

 Conc and rate varies with level and type of
stimulation


 Inconstant, underlying mechanisms partially
understood

 Produce final hypotonic solution

 Influence of tubular cells more when flow rate
is slow


 Predominant control – PARASYMPATHETIC

 Sympathetic stimulation shorter and less
strong

 Probable synergistic action


 Primary fluid secretion

 Protein secretion

 Vasodilatation

 Increased metabolism and growth

 Myoepithelial cell contraction

LARGE VOLUME LOW PROTEIN OUTPUT


 High protein secretion

 Vasoconstriction – decreased blood flow

 Myoepithelial cell contraction

LOW VOLUME HIGH PROTEIN OUTPUT


 Parasympathetic

◦ Ach binds to M3
Receptors

◦ Activation of G protein
Phospholipase C IP3 &
DAG Intracellular
Ca2+
release, Protein
exocytosis


 Sympathetic

◦ Noradrenaline binds to
α1, β1 receptors

◦ Activation of G protein
Adenylate Cyclase
activation
↑cAMP dependant Protein
Kinase protein exocytosis


 Unstimulated – Submandibular

 Stimulated – Parotid 2/3rd

 Acidic tastes – Max stimulation

 Sweet tastes – Least stimulation


 Psychic factors
 Circadian rhythm
 Diurnal variation
 Age
 Drugs
 Tricyclic antidepressants
 Phenothiazines
 Depression and anxiety states
 Dehydration, hemorrhage,


 Salivary Gland diseases

 Radiation sialadenitis

 Autoimmune sialadenitis

 HIV infection

 Iron overload

 Sarcoidosis

 Amyloidosis

 Cystic fibrosis


 Flow rate
 Source of secretion
 Type of stimulus
 Diurnal variation
 Diet
 Drugs – flow dependant components
 Hormones – mineralocorticoids, ovulation


 Disease states

 Sialadenitis
 Radiation damage
 Sjorgen’s syndrome
 Cystic fibrosis
 HTN
 DM
 Alcoholic cirrhosis
 Aldosteronism
 Chronic pancreatitis


 Valid medium, painless, non-invasive

 Hormone monitoring
 Unconjugated steroids
 Proportional to free unbound plasma levels
 Useful in field studies
 Estradiol, progesterone, testosterone


 Drugs
 Factors – lipid solubility, protein binding, molecular
size, flow rates
 Constant saliva / plasma ratio not established

 Microbial antigens, antibodies
 Hepatitis A, B, C
 HIV
 Immunisation status


 Tc 99m pertechnitate

 Scintigraphy – objective measure of its
uptake, concenteration, excretion


 Concentric shells of calcareous material
alternating with organic material

 Stasis of flow

 Distribution
 Submandibular gland – 92%
 Parotid – 6%
 Sublingual / minor salivary glands – 2%


 Scott-Brown’s Otolaryngology – 6th ed, Vol
1, Vol 5
 Otolaryngology Head & Neck Surgery –Charles
W Cummings, 4th ed, Vol 2
 Skandalakis’ Surgical Anatomy
 Last’s Anatomy – 9th ed
 Physiology – Berne & Levy, 5th ed


Anatomy and physiology of salivary glands

Anatomy and physiology of salivary glands

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Anatomy and physiology of salivary glands

Similar to Anatomy and physiology of salivary glands (20)

More from Supreet Sn

More from Supreet Sn (6)

Recently uploaded

Recently uploaded (20)

Anatomy and physiology of salivary glands