126
UNIT 1
Organization of the Body
4
Compound duct structure
Simple tubular
Example
Intestinal glands
Simple branched tubular
Example
Stomach (gastric)
glands
Compound tubular
Example
Duodenal glands of small intestine
Compound alveolar
Example
Mammary glands
Simple alveolar
Example
No important example
in humans
Simple branched alveolar
Example
Sebaceous (oil) glands
Compound tubuloalveolar
Example
Salivary glands
Tubular
secretory
structure
Alveolar
secretory
structure
(duct branches)
Surface epithelium
Duct
Secretory epithelium
Simple duct structure
(duct does not branch)
Figure 4.5
Types of multicellular exocrine glands.
Multicellular glands are classi´Čüed
according to duct type (simple or compound) and the structure of their secretory units (tubular,
alveolar, or tubuloalveolar).
(b) In holocrine glands, the entire secretory
cell ruptures, releasing secretions and
dead cell fragments.
Secretory
cell fragments
(a) Merocrine glands secrete their
products by exocytosis.
Secretory
vesicles
Figure 4.6
Chief modes of secretion in human exocrine glands.
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