Histology: Salivary gland, Esophagus, and Stomach

what are the major salivary glands?

• parotid

• submandibular

• sublingual

(these are all duct systems)

what are the minor salivary glands?

• Labial (lip)

• Buccal (cheek); molar

• Lingual (tongue)

• Palatine (hard and soft)

• Alveolar mucosa

• Floor of mouth

(short ducts or secrete directly into oral cavity)

what are components of saliva?

• water (97-99%)

• cells (lymphocytes, neutrophils, salivary corpuscles)

• proteins/enzymes

• mucin glycoproteins

• electrolytes (Na+, K+, Ca++, HCO3-, PO43-, Cl-, F-)

% of mucous secretion are from minor glands

70%

% of saliva is from major glands. minor glands?

90+% from major glands; 5-10% from minor gl

we secrete ____ ml of saliva per day

1000

what are the functions of saliva?

• protection, buffering

• solubilize food molecules

• moisten food

• initiate digestion

• control microbial flora

• promote healing

how does saliva protect and buffer?

• Moisten/lubricate oral mucosa, prevent drying, flush/cleanse/protect teeth, facilitate speech

• Neutralization of acids, maintain pH

  • HCO3-

how does saliva initiate digestion?

enzymes like alpha-amylase, lipase, RNase, DNase

how does saliva promote healing?

epidermal growth factor (EGF)

salivary gland

what are the components of salivary glands?

• serous units

  • acinar

  • round nucleus toward base

• mucous units

  • tubular

  • flattened nucleus

• mixed units/cells

• ducts

what do serous units secrete?

Watery fluid containing proteins

what do mucous units secrete?

Viscous fluid containing glycoproteins

Parotid Gland

(Serous; mucous rare)

Submandibular Gland

(Serous>Mucous)

Sublingual Gland

(Mucous>Serous)

parotid

• we know these are serous cells (dark staining, perfectly round nuclei)

submandibular

• darker staining + round nuclei = serous

• lighter staining + flattened nuclei = mucous

• more serous than mucous = submandibular

sublingual

• darker staining + round nuclei = serous

• lighter staining + flattened nuclei = mucous

• more mucous than serous = sublingual

what are the ductal elements of salivary glands?

• intralobular ducts

  • intercalated

  • striated

• interlobular ducts (excretory)

what kind of cells make up intercalated ducts?

cuboidal

what kind of cells make up striated ducts?

columnar

what kind of cells make up interlobular ducts?

pseudo-stratified

Striated ducts have eosinophilic cytoplasm due to large numbers of ______

mitochondria

parotid gland (intercalated vs striated ducts)

parotid gland (intercalated vs striated ducts)

striated ducts (nuclei located closer to apical surface)

what is the funciton of striated ducts?

Na+ reabsorption; K+, HCO3- secretion; influenced by adrenal steroid aldosterone

what is the funciton of excretory ducts?

Transport saliva to the oral cavity, generally do not modify the saliva

what cells are responsible for salivation in response to visual/neurological stimulation (before we even put food in mouth)?

myoepithelial cells (located between secretory cells and basement membrane)

myoepithelial cells

myoepithelial cells

myoepithelial cells

what are the functions of myoepithelial cells

support, contraction, antiangiogenesis, tumor suppressor activity, barrier against invasive epithelial neoplasms

C) striated duct

what type of glands are the minor salivary glands?

mixed (mucous > serous) OR mucous

except gustatory/Ebner glands are serous

what type of fluid is secreted from Ebner glands?

serous only

where are Ebner glands located?

near vallate and foliate papillae

what Chronic autoimmune disorder affects salivary & lacrimal glands leading to xerostomia & dry eyes, respectively?

Sjögren Syndrome

what is the 3rd most common autoimmune disease next to RA & lupus?

Sjögren Syndrome

t/f: there is a cure for Sjogren’s syndrome

false.

• Mild symptoms to severe disease

• Currently no cure, but treatment may help

what is sialoithiasis?

formation of calculi or mineralized concretions that may block a salivary duct

what condition may lead to periodic pain in ducts or gland as well as swelling of gland due to obstruction of duct by mineralized concretions?

Sialolithiasis

what is the condition characterized by dryness of mucous membrane of mouth resulting from reduction (hyposalivation) or absence (asialism) of saliva?

Xerostomia

what are some causes of Xerostomia?

• infections

• side effects of medications, chemotherapy & radiotherapy;

• autoimmune diseases (e.g., Sjögren syndrome);

• endocrine disorders (e.g., diabetes); anxiety

xerostomia places patients at risk for…?

tooth decay, opportunistic oral infections (bacterial, fungal), gum disease

t/f: xerostomia is a relatively common condition that affects more females than males.

true

what is the acute infectious disease that causes inflammation and swelling of the parotid gland [parotitis =inflammation of the parotid gland] with occasional involvement of other salivary glands?

mumps (epidemic parotitis)

what is the cause of mumps?

contagious infection by mumps virus

t/f: mumps is typically a childhood disease, although adults may be affected.

true

what is metastatic mumps?

may involve other organs (e.g., testes, ovaries, breasts, meninges)

Presentation: 13yr w/ 2d history of facial swelling on lt side; pain w/out fever or ear discharge; recently began tuba

Physical exam shows swelling of left cheek w tenderness on palation

Lab results show serum amylase 3x the normal amount.

What is the condition?

pneumoparotid

(CT shows air in left parotid gland and duct)

what is the treatment for pneumoparotid?

parotid massage = foamy secretions from duct

what are the layers of the GI lining?

what is the Muscular tube connecting pharynx to stomach?

esophagus

what are the layers of the mucosa?

• epithelium

• lamina propria

• muscularis mucosae

what are the layers of the esophageal mucosal lining?

SSNKE (epithelium)

lamina propria

muscularis mucosae

what are the components of esophageal submucosa?

loose CT

esophageal glands (*only esophagus and duodenum have submucosal glands)

what kind of muscle is found in the esophageal muscularis externa?

• inner circular/outer longitudinal

• upper 1/3 = skeletal muscle

• middle 1/3 = skeletal/smooth mixed

• lower 1/3 = smooth muscle

where is the esophageal adventitia located?

thorax

where is the esophageal serosa located?

abdominal cavity

what is the zigzag line in the stomach?

squamocolumnar mucosal junction (area where the esophagus's normal squamous mucosa transitions to the columnar mucosa of the stomach)

what is Barrett’s esophagus?

Abnormal squamocolumnar junction -metaplasia (to gastric or intestinal mucosa)

Short arrows: goblet cell mucins stained with alcian blue

b

A=MALT (mucosa associated lymphoid tissue)

B=surface mucous cells,

C=gastric pit

D=muscularis mucosa

B) squamocolumnar junction

b (gastric glands are in the mucosa)

b, A=parietal, B=Chief, C=gastric pit

are there submucosal glands in the stomach?

no

what type of muscles make up the muscularis externa of the stomach?

inner oblique (limited); middle circular; outer longitudinal (limited)

what are the stomach mucosal glands?

• cardial gastric glands

• gastric glands proper

• pyloric glands

which type of stomach mucosal gland is this:

• short pits; short glands

• Cells: mucous, stem, enteroendocrine, occasional parietal

• Short segment: <4mm

Cardial gastric glands

which type of stomach mucosal gland is this:

• short pits; long glands

• Cells: mucous neck, stem, parietal, zymogenic chief, enteroendocrine

Gastric glands proper (fundic glands)

which type of stomach mucosal gland is this:

• long pits; short glands

• Cells: mucous, stem, enteroendocrine, occasional parietal

Pyloric glands

Stomach: Surface Mucous Cells

Stomach: Surface Mucous Cells

Gastric glands proper

Mucous neck cells (fundus)

________ deficiency can lead to decreased rbc development (pernicious anemia)

Vitamin B12

which stomch cells secrete HCl an intrinsic factor which helps with vit B12 absorption in gut?

parietal

which stomach cells secrete pepsinogen and lipase?

chief (zymogenic) cells

which stomch cells are eosinophilic due to abundant mitochondria/

parietal cells