Let us look at the
It is called a polymorphonuclear neutrophil or simply
we often refer to them as being polymorphs.
Have a look at the cell in the middle image,
right in the middle that is a neutrophil.
It has got a very strange-shaped nucleus.
The nucleus has a number of lobes, dark blue
stained components and each of those lobes are
joined by a little tiny thread of part of
the nucleus. It is polymorphous nuclei differentiate
nuclear lobes and that is why we call it that
names as I've mentioned. Across on the right-hand
side, you can see the components of the cell
under the electron microscope, you can see
in those electron micrograph, a number of
little granules if you look very carefully
and they're reflected by specific staining that
we can do in the light microscope image you
see. In the case of neutrophils, it is that
even though you can see these granules within
the picture on the right, the electron micrograph
of these cells, it does not take up stain.
There are three sorts of granules that I will
explain in a moment within these neutrophils,
but unlike the two other granulocytes, it
just does not take up the stain that we use
in normal blood smears. So that is why it
is called neutrophil. And it has a label. It says
it lacks specific staining in the cytoplasm.
Look at the cytoplasm and it is just a very
clear pink shade. Well these neutrophils are very
very important because they are phagocytes.
They travel around the blood, then they enter
into tissue spaces where there happens to be
perhaps an invading pathogen, bacteria etc.
So their job is to go in first and to mop
up that debris and start to break it down.
They are the first cell to arrive at the site
of inflammation and they have three sorts
of granules. Some of the granules such as
the specific granules are designed or at least
contain antimicrobial peptides or enzymes
that break down these microbes that they are
attack and surround. Other granules such as
the azurophilic granules, they contain lysosomes.
Lysosomes are used by the cell to breakdown
the products that they've digested.
They ingest these products by digest them and they
use the lysosomes to eventually break down
those further components to be almost totally
nothing within the cell except maybe a little
bit of undigested product that they will eventually
eliminate. So azurophilic granules refer to
lysosome contain these hydrolytic enzymes.
In the neutrophil, we also have tertiary granules.
Remember I said the neutrophil are the first
cell to arrive at the site of inflammation.
And therefore they need to have a mechanism
to be able to burrows through connective tissue.
So there's tertiary granules contain different
sorts of enzymes such as collagenases, they
allow them to move through the connective
tissue very readily and therefore reach the
site of infection. You can see the nucleus
on the right-hand side, the electron micrograph
picture, it has got a lot of heterochromatin
and it is very hard to see the euchromatin
when you look at a light microscope image
of these cells as you see in the center.
The heavy amount of heterochromatin really indicates
that these cells are not doing their job when
you see them in blood. It is not until they
move into the connective tissue as I have
mentioned before that they actually do their
job and become activated and therefore they'll
become more euchromatic, which is a way of
looking at the cell and identify whether
it is very active or not.