Glands & Secretions Flashcards
Secretion involves three distinct cellular activities:
-uptake of simple materials from the Extracellular Fluid
-processing of these within the cell to produce a more complex product
-release or transport of these proteins
Excretion is the
Removal of waste
Glandular tissue is derived from
Secretory epithelium
Two types of glands, give two examples
-Exocrine (sweat glands, salivary glands)
-Endocrine (pancreas, thyroid)
Which type of gland releases their secretory products onto surface epithelium via ducts
Exocrine
Hormones are released
Directly into blood / lymph
Endocrine glands lack a
Duct
Secretion of products directly into blood or lymph is done through
Endocrine glands
3 modes of secretion in exocrine glands
-Merocrine (eccrine)
-Apocrine
-Holocrine
Most common form of exocrine secretion is
Merocrine (eccrine)
Which mode of exocrine secretion results in the death of a cell
Holocrine
Merocrine (eccrine) exocrine secretion and examples
-vesicles are released via Exocytosis when the vesicle membranes fuse with the cell membrane
-some sweat glands and salivary glands
Apocrine exocrine secretion and examples
-secretory vesicles accumulate at the apical portion of the cell, a mass of cytoplasm and vesicle are then pinched off
-mammary gland, some sweat glands
Holocrine exocrine secretion and an example
-secretory products accumulate and the cell ruptures/dies
-sebaceous glands
Glands can be classified based on (4)
-mode of secretion
-structure
-morphology
-nature of product
Two structures of exocrine glands
-unicellular
-multicellular
Unicellular exocrine gland is
Goblet cells of the digestive and respiratory tracts
Goblet cells secrete ___ that becomes ___
Mucin —> Mucous
Most exocrine glands are
Multicellular
Goblet cells are found
Amongst columnar cells of epithelium within the digestive and respiratory tracts
Mixing mucigen and H2O creates
Mucous
Mucigen is released by ___ secretion of the ____ cell
Merocrine; goblet
Goblet cell structure (3)
-theca (expanded apical portion) contains mucigen droplets
-basal nucleus
-basophilic cytoplasm
In multicellular exocrine glands, secretion
Is discharged from the cell surface into the duct and then to the epithelial surface
Multicellular exocrine glands can be classified according to morphology (2)
-duct system
-secretory end pieces
Three types of duct systems
-Simple (single and unbranched duct, may be coiled)
-Simple Branched (2+ secretory areas that empty into a common duct)
-Compound (branched duct system)
Three types of Secretory End Pieces
-Tubular
-Alveolar/Acinar (rounded cluster of cells)
-Tubuloalveolar (tubular region ending in a rounded alveolus)
Example of Simple Tubular Exocrine Gland
Intestinal glands
Example of Simple Coiled Tubular exocrine gland
Sweat glands
Example of Simple Branched Tubular exocrine glands
Stomach glands
Example of Simple Alveolar exocrine gland
Urethra
Example of Simple Branched Alveolar exocrine gland
Sebaceous gland
A lobe is __ and is separated by ___
Many lobules; collagenous connective tissue
Secretory portions of glands form __ which may cluster into __
Lobules; lobes
Connective tissue septae (2)
-where nerves, blood, and lymph vessels enter gland
-separates Lobes
Compound gland duct systems begin within the lobules as
Intercalated ducts
Intercalated ducts become
Intralobular (striated) duct
Intralobular (striated) ducts become
Intralobar Ducts (ie. within the LOBE)
Example of Compound Tubular exocrine gland
Brunner’s glands in duodenum
The exocrine pancreas is an example of what duct system
Compound alveolar
Example of Compound Tubuloalveolar exocrine gland
Salivary gland
Example of Compound Alveolar (Acinar) exocrine gland
Exocrine pancreas
Three types of secretory products of exocrine glands
-Mucous Glands (secrete mucin, a thick sticky glycoprotein)
-Serous Glands (watery and filled with enzymes)
-Mixed Glands (contain more than one cell type —> produce both mucous and serous secretions)
Most exocrine glands will secrete at a
Low level continuously
The rate of exocrine secretion is modulated by (3)
-hormones
-autonomic Innervation
-combination of both
Which gland is both exocrine and endocrine
Pancreas
What are the endocrine glands of the pancreas called
Islet of Langerhans
Secretory product of the thyroid is
Colloid; thyroglobulin
In the thyroid, the endocrine cells are
Arranged into follicles surrounding a mass of secretory product
Endocrine secretions are
Hormones (proteins and steroids)
Endocrine glands are adapted for
Storing and releasing products as required
Storage of products in endocrine glands is
Usually intracellular; in the thyroid it is stored in extracellular follicles
Endocrine glands are usually ___ secretion
Merocrine
Endocrine Glands (3)
-connection with surface epithelium is lost (ie. secretory cell has NO connection to epithelium)
-well vascularized
-secrete products directly into blood or lymph and transported throughout body to target organ/tissue
