2.5 Flashcards
(20 cards)
__________ are classified into three types on the basis of the site of secretion.
Glands
Three types of glands
- Exocrine
- Paracrine
- Endocrine
__________ glands secrete into a duct or onto a surface
Exocrine
______________ glands secrete into the bloodstream.
Endocrine
___________ glands secrete into the local extracellular space.
Paracrine
Exocrine glands
a. Unicellular glands are composed of a single cell (e.g., goblet cells in tracheal epithelium).
b. Multicellular glands
(1) Classification is based on two criteria:
(a) Multicellular glands are classified according to duct branching as simple glands (duct does not branch) or compound glands (duct branches).
(b) They are further classified according to the shape of the secretory unit as acinar or alveolar (saclike or flasklike) or tubular (straight, coiled, or
branched).
(2) A connective tissue capsule may surround the gland, or septa of connective tissue may divide the gland into lobes and smaller lobules.
(3) Glands may have ducts between lobes (interlobar), within lobes (intralobar), between lobules (interlobular), or within lobules (intralobular), such as striated and intercalated ducts.
(4) Multicellular glands secrete various substances.
(a) Mucus is a viscous material that usually protects or lubricates cell surfaces.
(b) Serous secretions are watery and often rich in enzymes.
(c) Mixed secretions contain both mucous and serous components.
(5) Mechanisms of secretion vary.
(a) In merocrine glands (e.g., parotid gland), the secretory cells release their contents by exocytosis.
(b) In apocrine glands (e.g., lactating mammary gland), part of the apical cytoplasm of the secretory cell is released along with the contents.
(c) In holocrine glands (e.g., sebaceous gland), the entire secretory cell along with its contents is released.
Exocrine glands:
___________ glands are composed of a single cell (e.g., goblet cells in tracheal epithelium).
Unicellular
Exocrine glands:
Multicellular glands: Criteria
Multicellular glands are classified according to __________ as ________ glands (duct does not branch) or ___________ glands (duct branches).
Duct branching; Simple; Compound
Exocrine glands:
Multicellular glands: Criteria
They are further classified according to the shape of the secretory unit as _______ or _______ (saclike or flasklike) or _________(straight, coiled, or
branched).
Acinar; Alveolar; Tubular
Exocrine glands:
Multicellular glands:
A connective tissue capsule may surround the gland, or septa of connective tissue may divide the gland into ________ and smaller _______.
Lobes; Lobules
Exocrine glands:
Multicellular glands:
Glands may have ducts between lobes (__________), within lobes (________),
between lobules (___________), or within lobules (________), such as striated and intercalated ducts.
Interlobar; Intralobar; Interlobular; Intralobular
Exocrine glands:
Multicellular glands: Secrete various substances
_________ is a viscous material that usually protects or lubricates cell surfaces.
Mucus
Exocrine glands:
Multicellular glands: Secrete various substances
________ secretions are watery and often rich in enzymes
Serous
Exocrine glands:
Multicellular glands: Secrete various substances
__________ secretions contain both mucous and serous components.
Mixed
Exocrine glands:
Multicellular glands: Mechanisms of secretions vary
- Merocrine
- Apocrine
- Holocrine
Exocrine glands:
Multicellular glands: Mechanisms of secretions vary
In ___________ glands (e.g., parotid gland), the secretory cells release their contents by exocytosis.
Merocrine
Exocrine glands:
Multicellular glands: Mechanisms of secretions vary
In __________ glands (e.g., lactating mammary gland), part of the apical cytoplasm of the secretory cell is released along with the contents.
Apocrine
Exocrine glands:
Multicellular glands: Mechanisms of secretions vary
In __________glands (e.g., sebaceous gland), the entire secretory cell along with its contents is released.
Holocrine
__________ glands may be unicellular (e.g., individual endocrine cells in gastrointestinal and respiratory epithelia) or multicellular (e.g., adrenal gland), and they lack a duct system. In multicellular glands, secretory material is released into fenestrated capillaries, which are abundant just outside the basal lamina of the glandular epithelium.
Endocrine
Endocrine glands may be ____________ (e.g., individual endocrine cells in gastrointestinal
and respiratory epithelia) or _____________ (e.g., adrenal gland), and they lack a duct
system. In multicellular glands, secretory material is released into fenestrated capillaries,
which are abundant just outside the basal lamina of the glandular epithelium.
Unicellular; Multicellular
