Membrane epithelium becomes glandular epithelium when it invaginates involutes into the tissue layer layers below forming a gland There are two main types of gland They are exocrine and endocrine ID: 539515
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Slide1
GLANDULAR EPITHELIUMSlide2
Membrane epithelium becomes glandular epithelium when it
invaginates / involutes into the tissue layer / layers below, forming a glandThere are two main types of gland. They are exocrine and endocrine. Slide3
FORMATION of Exocrine/Endocrine glandsForm
the same way. During prenatal development
, some epithelial cells form a downward fold (invagination) into the connective
tissue
These
invaginations
may be composed of one or more cells
and they are called
glands
.
Glands usually in
cuboidal
and
columnar
epithelium.Slide4
EXOCRINE GLANDSSlide5
In
exocrine glands, the original invagination develops into a duct. The duct is a passageway that remains open to the free surface.
Products are secreted to surface via the duct Slide6
Exocrine glands may be
unicellular or they may be multicellular.example : unicellular exocrine gland is the goblet cell. Produce
mucus. Located throughout the body
.Typical exocrine glands include sweat glands, salivary glands
,
mammary glands
,
stomach
,
liver
.Slide7
Multicellular
exocrine glands are divided into two general categories according to structuresimple (exocrine) gland
= connects to the free surface via an
unbranched duct.compound (exocrine) gland
=
connects
to the free surface via
branched
ducts
.
NOTE
: There are several variations in each of the above categories.Slide8Slide9
Both may be
further classified according to: shape of the part of the gland that produces the secretions.
These areas may be:tubular = secretion area is shaped like a tubealveolar
/ acinar = secretion area is shaped like a sacSlide10Slide11
ENDOCRINE GLANDS
In endocrine glands, the connection to the free surface is lost.Slide12
Endocrine glands secrete products
directly into the blood or lymph fluids because ducts are absent.
EXAMPLE: Pituitary
(hypophysis) 1. location
2. structure
a. posterior lobe: hormone storage
1.
oxytocin
2.
antidiuretic
hormone (ADH)
b. anterior lobe: hormone production
1. abnormalities:
hypersecretion
and
hyposecretion
2. regulation: hypothalamic factors Slide13Slide14
GLANDULAR SECRETIONS
(see Handout – no need to copy)1). merocrine
= The secretory cells (cells that produce the secretions) discharge only the secretions
they produce.2). apocrine = The secretion is produced in the secretory cell. It accumulates in the end
of
the
cell
(apical portion
).
The end of the cell pinches off
and the secretion is
released
along with the tip of the cell.
3).
holocrine
= The secretion is produced and accumulates in the
secretory
cell.
Then the cell
dies
, disintegrates
and is discharged from the gland along with the secretion.Slide15
Complete “Name that Tissue” and hand in!