5.5 – Cellular junctions, glands, and membranes Flashcards
the connections b/n one cell and another are called ___
cellular junctions
cellular junctions (functions)
enable cells to resist stress, communicate w/ each other, and control the movement of substances thru tissues
tight junctions (physical characteristics)
completely encircles an epithelial cell near its apical surface and joins it tightly tot he neighboring cells
the type of cell junction that holds cells together and seals off the space b/n adjacent cells making it difficult for substances to pass b/n them is a ___ junction
tight
what are the 2 broad classes of glands?
endocrine and exocrine
exocrine glands are classified according to their architecture – the ___ of their ducts and the appearance and extent of their ___
branching of their ducts
appearance and extent of their secretory portions
exocrine gland classifications:
simple
exocrine gland w/ a single, unbranched duct
exocrine gland classifications:
compound
exocrine gland w/ a branched duct
exocrine gland classifications:
tubular
if the exocrine gland’s duct and secretory portion are of uniform diameter
exocrine gland classifications:
acinar
if the exocrine gland’s secretory cells form a dilated sac, the gland is called acinar and the sac is an acinus/alveolus
exocrine gland classifications:
tubuloacinar (tubuloalveolar) gland
a gland w/ secretory cells in both the tubular and acinar portions
how would an exocrine gland that is branched w/ sacs at the end of each branch be classified?
compound acinar
smooth, skeletal, and cardiac are types of which tissue?
muscular
glands are classified not only by their structure but also by the nature of their ___
secretions
glands based on types of secretions:
serous glands (characteristics)
produce relatively thin, watery fluids (such as perspiration, milk, tears, and digestive juices)
glands based on types of secretions:
mucous glands (characteristics)
found in the oral and nasal cavities, among other places
secrete a glycoprotein called mucin –> mucin absorbs water and forms mucus
goblet cells are unicellular ___ glands
mucous
glands based on types of secretions:
mixed glands (characteristics)
ex. 2 pairs of salivary glands in the chin
contain both serous and mucous cells
produce a mixture of the 2 types of secretion
which glands produce relatively thin, watery fluids?
serous
what best describes tight junctions?
they consist of transmembrane cell-adhesion proteins around the upper part of a cell and hold neighboring cells together
exocrine glands are classified into ___, ___, and ___ types according to how they release their secretions
eccrine, apocrine, and holocrine
exocrine glands are classified eccrine, apocrine, and holocrine types according to how they release their ___
secretions
gland types based on modes of secretion:
eccrine secretion
aka merocrine glands
release their products by means of exocytosis
include the tear glands, salivary glands, pancreas, and most others
mammary glands secrete milk sugar and proteins by this method
gland types based on modes of secretion:
apocrine secretion
ex. secretes fat by a cell of the mammary gland
gland types based on modes of secretion:
holocrine secretion
cells accumulate a product and then the entire cell disintegrates –> becomes the secretion instead of releasing one (cell lysis)
tend to be relatively thick and oily, composed of cell fragments and the substances the cells had synthesized before disintegrating
ex. secretion by a sebaceous (oil) gland of the scalp
merocrine glands release their secretions by which process?
exocytosis
gland (def)
a cell or organ that secretes substances for use elsewhere in the body or for elimination as waste
by definition, a ___ is a cell or organ that secretes substances for use elsewhere in the body
gland
how do holocrine glands release their secretions?
cel lysis
which glands secrete hormones?
endocrine
an exocrine gland w/ a branched gland is said to be ___
compound
which glands secrete a glycoprotein called mucin?
mucous glands
membranes may be composed of ___ tissue only; ___ tissue only; or ___, ___, and ___ tissue
epithelial tissue only
connective tissue only
epithelial, connective, and muscular tissue
the 2 principal kinds of internal membranes are ___ and ___ membranes
mucous and serous
the largest membrane of the body is the ___ membrane
cutaneous
AKA the skin
cutaneous, mucous, and serous are terms that refer to which of the following?
membranes
glands classified as ___ glands release their secretions by exocytosis
merocrine
glands classified as merocrine glands release their secretions by ___
exocytosis
exocrine glands that release their secretions by disintegrating are classified as ___ glands
holocrine
exocrine glands that release their secretions by ___ are classified as holocrine glands
disintegrating
which type of gland consists of a secretory region and a duct running to a surface?
exocrine
how would an exocrine gland that is branched w/ sacs at the end of each branch be classified?
compound acinar
what are the 3 main types of body membranes?
cutaneous
mucous
serous
how do holocrine glands release their secretions?
cell lysis
cutaneous, mucous, and serous are terms that refer to which of the following?
membranes
