SALIVARY

Objectives: ◧ Editing file Describe the microscopic structure ◧ Important of the major salivary glands in ◧ Doctor notes / Extra correlation with function.

438 Team GNT Block ❏ Types Salivary Glands ❏ General Structure

Major Salivary Glands: Stroma: 1. Parotid. • C.T. capsule. 2. Submandibular. • C.T. septa dividing the glands 3. Sublingual. into lobes and lobules. • Reticular C.T. Minor Salivary Glands: 1. Labial (lips) Parenchyma: 2. Lingual (tongue) Acini. (secretory unite) 3. Buccal (cheek) system. 4. Palatine (Palate) Produce 5% of salivary output. Most of them are pure mucous or seromucous glands.

438 Histology Team – GNT Block 2 Types of Salivary Acini

Serous Acini: Mucous Acini: Mucoserous (Mixed) Acini:

• Contain only serous cells. • Contain only mucous • Mucous acini with a cap • Small, spherical, and with cells. of serous cells (serous a narrow lumen. • Larger, more tubular, and demilunes). Half moon shape • Secrete serous secretion with a wider lumen. thin fluid rich in enzymes, • Secrete mucous such as amylase and secretion. thick viscid lysozyme. secretion and rich in mucin

438 Histology Team – GNT Block 3 Cells of Salivary Acini

Myoepithelial cells Serous cells Mucous cells (basket cells):

• Pyramidal in shape. • Pyramidal or cuboidal. Contractile cells that embrace • Nuclei are round and basal. • Nuclei are flattened and basal. the basal aspect of the acini. Their contraction releases the Cytoplasm: Cytoplasm: secretion into the duct Deeply basophilic (due to Pale basophilic and vacuolated system. numerous RER), with apical (foamy) (due to dissolved acidophilic secretory granules mucinogen secretory granules). (rich in salivary amylase).

438 Histology Team – GNT Block 4 Duct System of Salivary Glands

1. Intralobular ducts (prominent): • Intercalated ducts: lined by small cuboidal cells. • Striated ducts: lined by low columnar cells.

2. Interlobular ducts: lined by simple columnar .

3. Main duct: lined by stratified columnar epithelium which becomes stratified squamous (nonkeratinized) in the distal end.

438 Histology Team – GNT Block 5 Major Salivary Glands

Parotid

• The largest . • Produces 60% of salivary • The smallest salivary gland. • Produces 30% of salivary output. output. • Produces 5% of salivary output. • Mixed but mostly serous • Mixed but mostly mucous. • Purely serous. (90%). • Mucous acini are capped by • Prominent intralobular ducts. • Mucous acini are capped by serous demilunes. • Secretion rich in: Amylase. Lactoferrin. serous demilunes. Lysozyme. Secretory IgA. Defensive enzymes lactoferrin (prevents bacteria from utilizing iron), IgA (antibody), and lysozyme (attacks bacterial cell wall). Amylase breaks down starch

438 Histology Team – GNT Block 6 Quiz 4- Which one of the following is lined by simple 1- Which one of the following is a major columnar epithelium. salivary gland: A. Main duct A. Sublingual B. Intercalated ducts Of Interlobular ducts B. Lingual C. Interlobular ducts C. Labial D. Intercalated ducts Of Intralobular ducts D. Palatine 5- Which one of the following gland secrete the 2- Serous acini secrete : most enzymes A. Thin fluid rich in hormones B. Thick fluid rich in enzymes A. Sublingual gland B. Parotid gland C. Thick fluid rich in mucin C. Submandibular gland D. Thin fluid rich in enzymes D. Palatine gland

3- Which of the following is true about 6- Which of the following is true about mucous cells submandibular gland A. Secrete serous secretion B. Deeply basophilic cytoplasm A. Serous gland C. Flattened nuclei B. The largest salivary gland D. Pale eosinophilic cytoplasm C. Secrete enzymes

D. Produce most of the salivary output

1.A 2.D 3.C 4.C 5.B 6.D 5.B 4.C 3.C 2.D 1.A 7 Team Leaders ◧ Abdullah shadid ◧ Sarah alflaij

Good luck