00:01
In this lecture, I am going to provide an
overview of the structure of exocrine glands
in the body and some indication of the function
of these glands. And I am also going to deal with
in more detail where appropriate when I review
the organ systems in the later lectures.
00:24
Exocrine glands are very important in a number of different
organ systems and it's important that first
of all you understand what a gland is and
know that basically these glands form two
major categories. They are the serous secreting
or mucous secreting. You need to also understand
the way in which glands secrete the components
that they have made and how we classify glands
or name them. And most importantly also it
is important to have some understanding of
the duct system of these glands because these
ducts within some glands modify the secretion
product produced via the secretory cells.
Now, there are a number of different types
of glands. As I explained I am mainly going
to concentrate in today's lecture on the exocrine glands.
01:25
They are glands that synthesize, then
secrete their products onto the surface.
01:34
They do so either directly such as we see in goblet
cells lining some epithelia or they secrete
their product via a tube called the duct or a conduit.
And as I mentioned earlier, some of these
ducts modify the secretion of the glands.
There are also endocrine glands.
02:00
These are glands that synthesize their products, but
then they secrete them into the extracellular
space around the glands. Because during development,
when the epithelium invaginated into underlying
connective tissue, the connection between
the surface of the epithelium and the secretory
invaginated epithelial cells is lost. And so
there is no way for these glands to secrete
their products. So therefore, they secrete
them into extracellular space and then those
secretory products move into the blood stream
and delivered to target organs often a
long way away from where these glands actually
synthesized the material. Another way in which
glands are classified or named is because
often some cells can secrete products that
affect their neighbors, and these are called
paracrine glands. These paracrine glands secrete
their products into the underlying interstitial
space and that diffuses to nearby cells
and affects their function. We will do with those
in another lecture. So basically the types
of glands are really classified on the way
in which they secrete their products and also
the way in which those products reach their
target tissues, either through a duct as in
exocrine glands or via the blood in endocrine
glands or just via diffusion along local interstitial
space to affect neighbour cells. It is
important to understand how glands release