Exam 3: Exocrine Glands Flashcards
Endocrine and exocrine glands are derived from
epithelial tissue
Endocrine glands synthesize and release
hormones that are transported in the blood to target cells or released into extracellular fluid
Exocrine glands secretions are transported in
epithelial-lined excretory ducts; secretions may be modified as they flow through duct system
Exocrine glands are classified based on
type of secretion, mode of secretion, and cell numbers
Exocrine gland classification based on type of secretion
Mucous glands, Serous glands, Mixed glands, Sebaceous glands
Mucous glands (exocrine) secrete
mucinogens, large glycosylated proteins
PAS positive
Mucus can form plugs, like in the airway
Mucin
thick protective fluid fromed when mucinogens are hydrated
Component of mucus
Examples of Mucous glands
goblet cells and mucous cells of stomach
Have light staining cytoplasm, flat nuclei pushed toward basal region of cell
Serous glands (exocrine) secrete
Serous fluid - watery, enriched with enxymes
Examples of serous glands
parotid gland and exocrine pancreas
Basophilic, round nucleus
Mixed glands (exocrine) secrete
serous and mucous
Examples of mixed glands
submandibular and sublingual glands
Sebaceous glands secrete
sebum - waxy, oily
found in skin
Clear cytoplasm, but centrally located and spherical nucleus
Classifications based on modes of exocrine gland secretion
Merocrine, Apocrine, Holocrine
Merocrine
Most common mode of secretion
Secretion occurs via exocytosis
There is no loss of plasmella or cytoplasm
Apocrine
Secretory product is released along with apical cytoplasm and plasmalemma, pinches off
Example of Apocrine secretion
Lipids from lactating mammary glands
Holocrine
Entire cell and its secretory product are released during secretion
Example of Holocrine secretion
sebaceous gland vesicles
Acne vulgaris
hair shaft penetrates Inflammatory state on cheek - because of sebaceous cells
hair follicle, elictating inflammatory and fibrotic responses
Inflammatory cells, giant cells, and fibrosis can be observed in skin with acne
Unicellular exocrine glands
individual secretory cells found in the epithelium
Basal domain has nucleus and organelles (width very narrow)
Apical domain has secretory product
Examples of unicellular exocrine glands
goblet cells in GI tube and respiratory airways
Multicellular exocrine glands
may be organized into secretory sheets (lining of stomach) or secretory tubules with no ducts; may also organize into secretory units and ducts
Acinus (alveolus) duct
terminal secretory portion is divided by partitions into sacs
Resemble a berry
Tubular duct
Terminal secretory portion is shaped as a tube
Can be coiled or branched (secretory units are branched but with single or no excretory duct)
Simple duct
single, unbranched excretory duct conveys the secretory product from secretory unit to epithelial surface
Compound duct
branching ducts converge to form a single duct that opens onto the epithelial surface
Septa from capsule
extend into gland to divide it into lobes and lobules
Intralobular ducts
found within the lobule of the exocrine gland
Interlobular ducts
found in the connective septa that separates lobules
Intercalated duct
Type of intralobular duct
Smaller of two
Lined by flattened cuboidal cells
Striated duct
Type of intralobular duct
Large of two
Mitochondria in basal area & nucleus pushed to apical domain
Myoepithelial cells (basket cells)
Contractile cells derived from epithelium that surrounds the secretory units of many multicellular glands and small ducts
Contains actin and myosin and cytokeratin
Connect to epithelial cells by desmosomes and gap junctions
Contraction of myoepithelial cells
expresses secretion from the gland
Compound glands
Parotid, Submandibular, Sublingual, Pancreas
Parotid gland classification
Compound acinar Contains Intralobular (intercalated and striated) and Interlobular ducts
Parotid gland secretion
only serous
Submandibular gland classification
Compound tubuloacinar
Contains intralobular ducts & interlobular ducts - intercalated ducts are short and striated ducts are prominent
Submandibular gland secretes
Mixed secretions - primarily serous
than mucin
Sublingual gland classification
Compound tubuloacinar
Intralobular ducts are less developed than those of other salivary glands
Sublingual duct secretion
Mixed secretions - primarily mucus
Serous cells almost exclusively exist as serous demilunes
Sjogren syndrome
autoimmune disease
Have dry eyes and dry mouth - decreased lacrimal and salivary gland secretions (become fibrotic and inflitrated with T cells)
Antibodies to ribonucleoproteins SS-A and SS-B
Occurs in women 50-60
Difficulty swallowing, speaking, and tasting
Enlarged Parotid gland and lymph nodes
Pancreas classification
Compound acinar
Similar to parotid gland but has islets of Langerhans, centroacinar cells, and absence of striated ducts
Pancreas ducts
Intercalated ducts - centroacinar cells represent intra-acinar segment
Larger intralobular ducts
Interlobular ducts
Duct cells secrete bicarbonate
Unicellular
Goblet cell
Multicellular sheet
Luminal surface of stomach
Simple acinar
Paraurethral glands
Simple branched acinar
Sebaceous gland
Simple tubular
Intestinal glands
Simple coiled tubular
Sweat glands
Simple branched tubular
Glands of stomach
Duodenal glands
Compound acinar
Pancreas
Parotid
Compound tubular
Bulbourethral glands
Compound tubuloacinar
Submandibular
Sublingual
