L22: Exocrine Glands Flashcards
What tumors develop from glands? Which are benign, which are malignant?
- Adenomas: benign
- Adenocarcinomas: malignant
How are exocrine glands classified?
- ) Type of secretion: mucous, serous, mixed, sebaceous
- ) Mode of secretion: merocrine, apocrine, holocrine
- ) Cell numbers: unicellular, multicellular
Discuss types of glands based on type of secretion. Include examples of glands for each type.
- ) Mucous glands: secrete mucinogens (PAS+ large glycosylated proteins) that when hydrated form thick fluid called mucin in mucous. Eg. Globlet cells, mucous cells of stomach, airway epithelium
- ) Serous glands: secrete watery fluid enriched with enzymes. Eg. Parotid gland and exocrine pancreas
- ) Mixed glands: secrete serous and mucous secretory units. Eg. Submandibular and sublingual glands
- ) Sebaceous glands: secrete oily, waxy substance called sebum. Eg. Glands of skin
Discuss classification of glands by mode of secretion
- ) Merocrine: secretion via exocytosis (no loss of PM or cytoplasm)
- ) Apocrine: secretion released at apical cytoplasm and PM
- ) Holocrine: entire cell and secretory product released
What mode of secretion to lactating mammary glands make use of?
Example of glands that utilize the holocrine mode of secretion
Name and describe how exocrine glands are classified by cell numbers
- ) Unicellular: individual secretory cells found in epithelium. Eg. Goblet cell in GI tube and respiratory airways
- ) Multicellular: cells organized into secretory sheets or tubules with no ducts (surface mucous cells lining stomach) OR cells may organize into secretory units and ducts
Two types of duct systems for glands
- ) Simple: single, unbranched excretory duct that conveys the secretory product from secretory unit to epithelial surface. Some simple glands don’t have the excretory duct (such as intestinal glands and glands of stomach)
- ) Compound: branching ducts converge to form a single duct that opens onto epithelial surface
How are glandular ducts named?
- ) Intralobular: within lobule
a. ) Intercalated ducts
b. ) Striated ducts - ) Interlobular: found in CT septa that separate lobules
- ) Interlobar/simple lobar: receive interlobular ducts and drain lobes of gland
- ) Main duct
Classification of parotid glands. Describe and include secretion type
- Compound acinar
- Purely serous gland
- Have intralobular ducts (intercalated and striated) and interlobular ducts
Classification of submandibular glands. Describe and include secretion type
- Compound tubuloacinar
- Mixed gland with secretions that are primarily serous from demilune cells
- Have intralobular ducts (intercalated ducts are short and striated ducts are prominent) and interlobular ducts
Classification of sublingual glands. Describe and include secretion type
- Compound tubuloacinar
- Mixed gland with secretions being primarily mucus, serous cells exist almost exclusively as serous demilunes
- Intralobular ducts are less developed
Classification of pancreas
- Compound acinar
- Similar to parotid, distinguished by presence of islets of Langerhans, which are centroacinar cells (unique feature) and absence of striated ducts
- Intercalated ducts, large intralobular ducts, interlobular ducts, duct cells secrete bicarbonate
Key to telling difference between pancreas and parotid?
- No striated ducts in pancreas
Classification of goblet cell
- Unicellular
Classification of glands in luminal surface of stomach
- Multicellular sheet
Classification of paraurethral glands
- simple acinar
Classification of sebaceous glands
- simple branched acinar
Classification of intestinal glands
- simple tubular
Classification of sweat glands
- Simple coiled tubular
Classification of glands of stomach and duodenal glands
- simple branched tubular
Classification of bulbourethral glands
- Compound tubular
