Glands
What parts of a gland do the terms "tubular" and "acinar" refer to?
"tubular" and "acinar" (rounded) refer to the general shape of the group of cells comprising a gland's secretory portions
3 types of glands (based on site of secretion)
1. exocrine 2. endocrine 3. paracrine
3 types of release mechanisms of glandular secretory products
1. merocrine 2. apocrine 3. holocrine
stain used for serous glands
H&E H: basal E: apical
what is a gland
a single or group of cells specialized for secretion
adenoma
benign growth arising from the epithelium lining a gland
endocrine glands secrete directly into ___
blood stream (no duct)
Which of the following processes is similar to the merocrine type of secretion? a. pinocytosis b. endocytosis c. exocytosis d. phagocytosis e. receptor-mediated endocytosis
c. exocytosis
glands are protrusions into ___
connective tissue
Serous demilunes are seen in which of the following glands? a. parotid b. gastric c. sebaceous d. submandibular e. pancreas
d. submandibular
holocrine release mechanism
disintegrating cells with contents become secretion (e.g. sebaceous gland, tarsal glands of eyelid)
exocrine glands have [ducts/no ducts], while endocrine glands have [ducts/no ducts]
ducts no ducts
compound tubular
duodenum (submucosal)
simple coiled tubular
eccrine (skin) sweat gland
mucous glands stain image
empty looking (mucous removed) flattened nuclei at base
merocrine (eccrine/epicrine) release mechanism
exocytosis (e.g. salivary, pancreatic acinar cells, and some sweat glands)
endocrine glands secrete
hormones (thyroid, adrenal)
simple tubular
large intestine
paracrine glands secrete
local EC space (enteroendocrine cells in GIT)
adenocarcinoma
malignant growth arising from the gland
Which mode of secretion occurs most commonly among glands?
merocrine / epicrine / eccrine
multicellular exocrine glands:
more than one secretory cell ex: stomach mucosa
saliva
mostly watery; contains ions, proteins, mucous, enzymes, antibodies, electrolytes, salivary amylase, and lysozymes
Why do serous cells typically stain much better than mucous cells?
mucous cells contain mainly granules of mucopolysaccharides which react poorly with H&E, serous cells are rich in rER (basophilic) and acidophilic protein filled granules
Exocrine glands in which the acini all produce a secretion of heavily glycosylated, hydrophilic proteins are an example of which type of gland?
mucous gland
compound tubuloacinar
neck region & oral cavity submandibular salivary
which glands contain both exocrine and endocrine parts
pancreas
compound acinar
pancreas (exocrine portion) mammary gland
apocrine release mechanism
pinching off apical portion of cell (e.g. lactating mammary gland)
striated ducts
reabsorb Na and Cl ions, secrete K & bicarb ions into saliva
exocrine glands secrete
saliva, sweat, mucous, acid, etc.
mixed gland secretes
serous demilune: both serous (crescent) and mucous glands (full)
types of duct branching
simple (not branched) compound (branched)
unicellular exocrine glands:
single cell type ex: goblet cell (respiratory tract, intestines)
branched acinar
stomach (cardia) sebaceous (skin)
simple branched tubular
stomach (pylorus) uterus endometrium
What exactly is branched or not branched in simple and compound glands, respectively?
the ducts draining a gland's secretory portions determine whether a gland is "simple" or "branched"
mucous glands secrete
thick viscid with highly glycosylated glycoproteins
types of shapes of secretory unit
tubular acinar/alveolar tubuloacinar
two classifications of exocrine glands
unicellular and multicellular
simple acinar
urethra
serous glands secrete
water secretion rich in proteins
