Lecture 4 Salivary Glands Flashcards
EXOCRINE GLANDS
Secretions are emptied directly into location where it is being used via a duct.
Classified into 4 characteristics
1. Duct system
2. Shape of secretory unit
3. Mode of secretion
4. Nature of secretion
- TYPE OF DUCT
Compound:
• branching of a duct where the secretory unit empties into small ducts and these join to form larger ones.
Simple:
• one duct which does not branch.
- SHAPE OF SECRETORY UNIT
- MODE OF SECRETION of Exocrine Gland:
MEROCRINE GLANDS:
secrete product through free surface, no loss of cytoplasm/cell (through exocytosis).
- Ex: salivary glands, pancreas.
APOCRINE GLANDS:
• secrete small amounts of cytoplasm/cell with secretory product.
• apical portion pinches off and detaches
• apical - apocrine
- Ex: mammary glands.
HOLOCRINE GLANDS:
• entire cells are discharged as secretion
• whole cells - holocrine
- Ex: sebaceous glands.
What do globlets secrete
Mucin
TYPE OF SECRETION (pg. 134)
3 types
• Serous:
- clear, watery with protein.
- contains digestive enzyme amylase (carbohydrates digestion)
• Mucous:
- cloudy, mucin (glycoproteins) with water
• Mixed:
- mixture of serous and mucous fluid.
Secretory cells and Acini:
Secretory cells and Acini:
• cells are found in a group, or acinus (plural, acini), looks like a cluster of grapes.
• each acinus is located at the terminal part of the gland connected to the ductal system, with many acini within each lobule of the gland.
• acinus consists of a single layer of cuboidal epithelial cells surrounding a lumen (central opening) where the saliva is deposited after being produced by the secretory cells.
Secretory cells and Acini
Salivary glands
What is the central opening surrounding each acinus called?
• C. Lumen
• Which type of epithelial is a acinus made up of?
• Which type of epithelial is a acinus made up of?
• C. Cuboidal Epithelial Cells
Salivary glands are?
• Compound tubular-alveolar merocrine glands.
All compound salivary glands are surrounded by a capsule of connective tissue which provides support for the lobes (the connective tissue make up
20% of the gland volume)
• Lobes are further subdivided into lobules which contain glandular units (units with acini).
The connective tissue partitions:
- between lobes = interlobar septa
- between lobules = interlobular septa
The duct attached to an acinus (terminal part of the gland) is called intercalated duct
What is Intercalated duct?
The duct attached to an acinus (terminal part of the gland) is called intercalated duct
Intercalated Ducts
INTERCALATED DUCTS:
•
•
•
-hollow tube attached to acinus
:-lined with simple cuboidal epithelium -cells that do not produce secretions, only serve as a passageway for saliva
This duct is lined with simple columnar epithelium and may have basal striations:
C. Striated duct
Striated Ducts
STRIATED DUCTS:
• connected to intercalated ducts
• lined with simple columnar epithelium
• cells may have basal
striations(mitochondria)
•
•
serve as passageway for saliva
cells resorb and excrete electrolytes.
Excretory/ Secretory Ducts
EXCRETORY/SECRETORY DUCTS:
• starts as pseudostratified columnar epithelium
•
•
changes to stratified cuboidal
and ends as stratified squamous epithelium in oral cavity
• serves as passageway for saliva
2 types of salivary Glands
• Major salivary glands carry their secretion some distance to the oral cavity by a main duct and secrete approximately 90% of the saliva
• Minor salivary glands empty their products directly into the oral cavity by short ducts
• Both are composed of either serous or mucous cells or a combination of both called serous demilunes
• The functional unit of the salivary gland is the alveolus or acinus.
• T/F
If a salivary gland is composed of both serous and mucous cells it is called serous demilunes
True
Major Salivary Glands
3 Types:
- Parotid
- Submandibular
- Sublingual
PAROTID SALIVARY GLAND
• Largest, encapsulated gland.
Located behind mandibular ramus, anterior and inferior to the ear, between the skin of the cheek and the masseter muscle.
A parotid duct (Stenson’s duct) passes from the gland in through the buccinator muscle entering the mouth and exiting on the inner surface of buccal mucosa opposite maxillary 2nd molar at the parotid papilla.
The duct system within the gland consists of long intercalated ducts and short striated ducts with basal striations.
• It contains only serous acini therefore the secretion is mainly serous.
• It contributes roughly 25% of the saliva into the oral cavity.
What percent % of total saliva volume does Submandibular
Gland produce?
B. 60-65%
SUBMANDIBULAR SALIVARY GLAND
• Medium capsulated gland
-The submandibular duct (Wharton’s
Duct) open under the tongue near the frenum at the sublingual caruncle
• Located in the floor of the mouth in the submandibular fossa posterior to the sublingual gland
-The duct system consists of short intercalated ducts and long striated ducts with basal striations.
-Mixed gland containing both secretions, but serous dominates
Approximately 60 to 65% of total salivary volume.
Stenson’s duct is associated with:
Stenson’s duct is associated with:
A. Parotid gland
• T/F
• The sublingual gland is located posterior to the submandibular gland.
False
What percent % of saliva is produced by Major Salivary
Glands?
90 percent
SUBLINGUAL SALIVARY GLAND
Smallest major gland without a capsule.
• Located in the floor of the mouth in the sublingual fossa anterior to the submandibular gland.
• Drained by several small ducts that J to form Bartholin’s duct where it or up at the sublingual caruncle
• Mixed gland but mucous dominates.
Approximately 10% of total salivary volume
What type of secretion is cloudy, mucin (glycoproteins) with water?
B. Mucous Secretion
Ducts of the Major Salivary Glands
Ectopic sebaceous glands are also know as:
Fordyce Granules
SALIVA
Approximately 640 ml (2.7 cups) of saliva is produced daily by humans.
Function:
- Moistens food and helps bind food particles together.
- Important in speech and articulation.
- Begins digestion (amylase) of carbohydrates.
- Helps cleanse the mouth and aids in swallowing.
- Contains calcium and phosphate, which may aid in the remineralization of the enamel surface and reverse the action of dental caries.
- Regulates pH in the mouth (buffers the acidity concentration and keeps it neutral at about 6.5 to 7.5 favorable range for the action of the enzymes).
CLINICAL CONSIDERATIONS:
Fordyce Granules
• ectopic (misplaced) sebaceous glanc
• 60-70% of adults have them
• variation of normal
Mucocele
• accumulation of saliva in mucosa due to trauma to minor salivary duct
Sialolith
Sialolith
• salivary stones, blocks salivary flow
• can cause a ranula to form
• The submandibular duct is called?
Wharton’s Duct
Which duct opens under the tongue near the frenum at the sublingual caruncle?
B. Wharton’s Duct
C. Bartholin’s Duct
Xerostomia
• aka dry mouth
• when salivary flow decreases or is absent, bacteria flora increases, calculus increases, periodontal disease progresses faster.
Possible causes????
Meds, chemo, mouth breathers, smoking
What produces approximately 10% of total salivary volume?
B. Sublingual Glands
Salivary stones that block salivary
flow are called:
B. Sialoliths
Label diagram
T- Capsule. U-Lobes
V- Lobule. R- Acini
S- duct system
Q- paratoid
S- sublingual
Ranula
CLINICAL CONSIDERATIONS
• TUMOURS:
- a variety of benign and malignant tumors can involve any of the salivary glands
• DEGENERATIVE DISEASE:
salivary and lacrimal glands are subject to an autoimmune destructive disease (Sjogren’s syndrome), which results in dry eyes and mouth.
Benign salivary tumor
Malignant salivary tumor