Hematopoiesis | Hematologic System Diseases | NCLEX-RN | Khan Academy
Summary
TLDRThis educational script explores the fascinating process of hematopoiesis, the formation of blood cells within the bone marrow. It begins by illustrating the components of blood, including red blood cells, platelets, and white blood cells, and then delves into their origin from hematopoietic stem cells. The script differentiates between myeloid and lymphoid lineages, detailing the unique characteristics of T and B lymphocytes, erythrocytes, megakaryocytes, and various types of white blood cells like monocytes, neutrophils, basophils, and eosinophils. It concludes with the developmental stages of these cells, from blasts to cytes, offering a comprehensive yet concise overview of blood cell production.
Takeaways
- 🩸 Blood vessels contain various cells such as red blood cells, platelets, and white blood cells, but are not the site of their production.
- 🦴 Blood cells are produced in the bone marrow, which is a red spongy tissue found in the central cavity of bones.
- 🌱 Hematopoiesis, the process of blood cell formation, originates from hematopoietic stem cells within the bone marrow.
- 🔬 Hematopoietic stem cells differentiate into two main cell lineages: myeloid and lymphoid groups.
- 🛡️ Lymphoid cells include T cells (T-lymphocytes) and B cells (B-lymphocytes), which are key components of the immune system.
- 🔴 Red blood cells, or erythrocytes, lack nuclei and have a biconcave disc shape, appearing paler in the center compared to the edges.
- 💔 Megakaryocytes are large cells that produce platelets through the release of cytoplasmic fragments.
- 🛑 White blood cells of the myeloid group include monocytes, which are known for engulfing bacteria through a process called phagocytosis.
- 🔬 Neutrophils have a multi-segmented nucleus and are a primary component of pus, playing a crucial role in the body's defense against infections.
- 🔵 Basophils are characterized by their blue granules and are involved in immune responses, particularly in allergies.
- 🔴 Eosinophils contain red granules and are involved in combating parasitic infections and modulating inflammation.
- 📚 Immature blood cells are referred to as 'blasts' and mature forms are termed 'cyte', with the exception of neutrophils, basophils, and eosinophils, which develop from a myeloblast.
Q & A
Where are blood cells made?
-Blood cells are made inside the bone marrow, which is located in the central cavity of bones.
What is hematopoiesis?
-Hematopoiesis is the process of forming blood cells. 'Hemato' means blood, and 'poiesis' means to form or make.
What is the origin cell for all blood cells?
-The origin cell for all blood cells is called a hematopoietic stem cell.
What are the two main cell lineages that hematopoietic stem cells give rise to?
-Hematopoietic stem cells give rise to two main cell lineages: the myeloid group and the lymphoid group.
What are the two types of lymphoid cells?
-The two types of lymphoid cells are T-lymphocytes (T cells) and B-lymphocytes (B cells).
What are erythrocytes and what is unique about their appearance?
-Erythrocytes are red blood cells. They have a biconcave shape, making the center of the cell much lighter than the edges due to the concentration of hemoglobin.
What are megakaryocytes and what do they produce?
-Megakaryocytes are large cells in the bone marrow that produce small cell fragments called platelets.
Describe the function of monocytes.
-Monocytes are white blood cells that protect against bacteria and viruses by engulfing and digesting them, a process known as phagocytosis.
What is a unique feature of neutrophils?
-Neutrophils have a multi-segmented nucleus, which is a distinguishing feature.
How can basophils be identified?
-Basophils can be identified by their bright blue granules in the cell cytoplasm.
What makes eosinophils distinct?
-Eosinophils are distinct due to their bright red granules in the cell cytoplasm.
What are the immature forms of blood cells called?
-The immature forms of blood cells are called blasts.
What happens to blasts as they mature?
-As blasts mature, they become cytes, which are the mature forms of the cells.
Which cell do neutrophils, basophils, and eosinophils develop from?
-Neutrophils, basophils, and eosinophils all develop from a myeloblast.
Outlines
🩸 Blood Cells and Hematopoiesis
This paragraph introduces the process of drawing blood vessels and the various cells found within them, including red blood cells, platelets, and white blood cells. It explains that these cells are not produced in the blood vessels but are instead made in the bone marrow, a spongy tissue inside the bones. The concept of hematopoiesis is introduced, which is the formation or making of blood, derived from a hematopoietic stem cell. This stem cell is the origin of all blood cells and gives rise to two main cell lineages: the myeloid and lymphoid groups. The lymphoid group is further detailed, describing T cells (T-lymphocytes) and B cells (B-lymphocytes), both of which have large nuclei taking up most of the cell volume.
🔬 Myeloid Cells and Their Development
The second paragraph delves into the myeloid group of cells, which includes red blood cells (erythrocytes), megakaryocytes, monocytes, neutrophils, basophils, and eosinophils. Red blood cells are highlighted for their lack of a nucleus and their biconcave shape, which resembles a dumbbell. Megakaryocytes are unique for giving rise to platelets through cytoplasmic fragments. Monocytes are characterized by their kidney bean-shaped nucleus and their role in engulfing bacteria. Neutrophils are recognized for their multi-segmented nucleus and presence in pus. Basophils are distinguished by their blue granules in the cytoplasm, likened to a blueberry muffin, while eosinophils are noted for their red granules. The paragraph concludes by explaining the developmental stages of these cells, starting from blasts to cytes, with a special note on the development of neutrophils, basophils, and eosinophils from a myeloblast.
Mindmap
Keywords
💡Blood vessel
💡Bone marrow
💡Hematopoiesis
💡Hematopoietic stem cell
💡Myeloid group
💡Lymphoid group
💡T-lymphocyte
💡B-lymphocyte
💡Erythrocyte
💡Megakaryocyte
💡Platelet
💡Monocyte
💡Neutrophil
💡Basophil
💡Eosinophil
💡Blasts
💡Cytes
Highlights
Drawing of blood vessel including red blood cells, platelets, and white blood cells.
Blood cells are not made in the blood but inside the bone marrow.
Bone marrow is the site of hematopoiesis, the process of forming blood.
Hematopoietic stem cells give rise to all different blood cells.
Blood cells differentiate into myeloid and lymphoid groups.
T cells and B cells are types of lymphoid cells, often referred to as naked nucleus cells due to their large nuclei.
Erythrocytes, or red blood cells, are characterized by their lighter center compared to their edges.
Megakaryocytes give rise to platelets through cytoplasmic blebbing.
Monocytes have kidney bean-shaped nuclei and engulf bacteria by surrounding them.
Neutrophils have a multi-segmented nucleus and are the main component of pus.
Basophils contain bright blue granules in their cytoplasm, resembling blueberry muffins.
Eosinophils have bright red granules and sometimes a nucleus in two pieces.
Immature blood cells are called blasts, and mature cells are called cytes.
Neutrophils, basophils, and eosinophils all develop from the same precursor cell, a myeloblast.
Discussion on hematopoiesis ends with the differentiation process from blasts to cytes.
Transcripts
Voiceover: I'm gonna start by drawing a blood vessel.
Inside the blood vessel I'm gonna draw in
some of the cells that you'd expect to see in normal blood.
I'm gonna put in a few red blood cells.
I'm gonna draw in a couple of platelets
which are just fragments of cells
and then I'm gonna put in a few white blood cells.
Even though all of these cells are found in the blood
they're actually not made there.
The cells in the blood are made inside the bone.
If you were to take a cross section of bone,
if you were to take a slice like this
and you looked at it,
you'd see that on the inside of bone
there's a central cavity.
This is the outside part of the bone.
The hard part and this is the central cavity.
Inside that cavity there's this red spongy tissue.
That stuff is called bone marrow.
Bone marrow.
Bone marrow is where all of these blood cells are made.
It's the site of hematopoiesis.
Hemato means blood
and poiesis means to form or to make.
Hematopoiesis is just a scary Greek word
that means to make blood.
Let's take a look at what goes on inside the bone marrow.
What's interesting is that
as different as all of the blood cells are
they all actually originate from the same cell
and that cell is called a hematopoietic stem cell.
This stem cells gives rise
to all of the different cells that you see in the blood.
It gives rise first to two different cell lineages
or two different cell groups.
First there is the myeloid group.
Myeloid group.
which is different from the lymphoid group.
The lymphoid group.
All of the cells that you see in the blood
belong to either the myeloid group
or the lymphoid group.
The lymphoid group includes
two different types of blood cells.
First there is the T cell
or actually that's too big
because this is a very little cell.
That seems about right.
There's a T cell and the majority of the cell
is taken up by the cell's nucleus,
and that's what I'm shading in over here.
So much so that this cell has a nickname.
It's often referred to as a naked nucleus
because it looks like the nucleus
isn't surrounded by very much cytoplasm.
This is a T cell or a T-lymphocyte.
T-lymphocyte.
It's very similar in appearance
to the other type of lymphoid cell.
This cell also has a nucleus
that takes up the majority of the cell
and this cell is a B cell or a B-lymphocyte.
B-lymphocyte, lymphocyte.
Those are the two different types of lymphoid cells.
What about the different types of myeloid cells.
For starters we have a red blood cell.
I guess we should draw that in red.
This is also very small cell.
I'm gonna shade in this cell
so that I can show you that the center of this cell
is much lighter than the edges
or the periphery of the cell.
This is not the cell's nucleus, guys
because we know that red blood cells
don't have nuclei.
What I'm trying to show is that the center of the cell
is much lighter than the periphery of the cell.
I guess I could do a better job of that
if I showed you what this cell looks like on its side.
This is what a red blood cell looks like
when it's laid on its side.
It kind of looks like a dumbbell
where the edges are much thicker
or much wider than the center.
The edges would since they're thicker
they would be much more densely packed with hemoglobin.
Since we know that hemoglobin
is what gives red blood cells their red color,
the edges would then be darker than the center.
Since the center is much thinner
it would have a lot less hemoglobin.
It would be a lot paler in comparison.
We said that this is a red blood cell
but since in science
we never use a plain and ordinary name of things
we call this an erythrocyte.
Erythrocyte which is just a fancy name
for a plain old red blood cell.
What are some of the other types of myeloid cells?
We have this one cell that I'm drawing in over here.
You might say well, that looks nothing like a cell
and you'd be totally right.
This is a very odd-looking, very large cell
and it's called a megakaryocyte.
Even if you never heard of a megakaryocyte before
you may have heard of what it gives rise to
because a megakaryocyte gives off
little blebs of its cytoplasm
to form this small cell fragments
and these fragments are known as platelets.
You may have heard of the platelets before.
The rest of the myeloid cells
are actually different types of white blood cells.
For example you have this one type of white blood cell
and the rest of these white blood cells
are about twice the size of a red blood cell
so that looks like it's twice the size
of a red blood cell to me.
This cell is called a monocyte.
It's known for having this nucleus
that's in the shape of a kidney bean.
That kind of looks like a kidney bean to me.
This is a really cool white blood cell
because it protects us from bacteria
and viruses and other invading organisms
just like any other white blood cell does
but it does so in a very interesting way.
Let's say that this was a bacterium
or actually, no I like the color pink
so let's use a color I don't like.
Let's say that this was a bacterium.
The monocyte would defend us against it.
It would attack this bacterium
by engulfing itself around the bacterium.
When it does that it kind of looks like
it's eating the bacteria.
It looks like its eating the bacterium.
That's a very interesting way
of dealing with these invading organisms.
Let's clear out that.
Mono actually refers to the fact that
this cell has a nucleus that's in one piece
and I guess a lot of these cells have nuclei
that are in one piece.
It makes us wonder what types of cells
have nuclei that are not in one piece
and that would bring us to a neutrophil.
This is a neutrophil.
A neutrophil.
It has a nucleus like I'm drawing in
that is broken up into several different pieces or segment.
The segments are still held together
by little pieces of string.
This is called a multi segmented nucleus.
Even if you've never heard of a neutrophil before
I'm sure you've seen them before
and how do I know that?
It's because neutrophils
are actually the main component of pus.
If you like anybody else has ever popped a pimple
you've looked at a bunch of neutrophils.
What are the other types of myeloid cells?
Well, we have this one cell that's called a basophil.
Basophil.
It looks something like this.
You might say, well, that looks
an awful lot like a monocyte
and you'd be completely correct
except this cell has a very unique feature
that the monocyte doesn't have,
and that is that it has these bright blue granules
in its cell's cytoplasm.
That make it stick out.
The way I like to think of a basophil is like
a basophil is like a blueberry muffin
and that reminds that it has these
bright blue granules in its cell's cytoplasm.
For the last type of myeloid cell we talked about.
Whoops.
For the last type of myeloid cell that we talked about
is an eosinophil.
It's an eosin-O-P-H, P-H-I-L, eosinophil, okay?
It has a nucleus that can sometimes be found
in two pieces.
This is the first piece and this is the second piece
but that's not what makes it so unique.
What it's really well known for
is the fact that it has these bright,
beautiful red granules in its cell cytoplasm.
Those are all of the different blood cells
with all the lymphoid cells on this side
and all the myeloid cells on this side.
It turns out that all of these cells
don't directly develop from hematopoietic stem cell.
Instead they undergo multiple stages of development
to mature into their adult form,
but don't worry guys we're not gonna hash out
each of those different forms and their names
and physical characteristics.
Instead we're gonna make a very general statement.
I guess we could put that up here.
We're gonna say that the immature forms.
the immature forms of all these cells
are called blasts.
When the blast mature, they mature
they are called cytes.
Let me show you what I mean.
To spare you guys the agony
of having to watch me draw out
all of those different forms
I just pasted them in here.
We can see here that what we said about
the immature forms being called blasts
and the more mature form being called cytes is true.
The T-lymphocyte develops from a T lymphoblast
just like an erythrocyte develops
from an erythroblast
and a megakaryocyte develops from a megakaryoblast.
You guys get the pattern.
The only wrench I'm gonna throw into this pattern
is with the neutrophil, basophil and eosinophil
which all actually develop from the same cell
and that cell is called a myeloblast.
I think that that's a reasonable place
to end our discussion on hematopoiesis.
Weitere ähnliche Videos ansehen
Hematology - Introduction - Hematopoiesis: Let's Make RBCs, WBCs, and Platelets -Hematology Playlist
Video Praktikum Systema Cardiovascular
Plasma and Blood Cells (RBCs, WBCs, and Platelets) - Hematology and Physiology
G11 En bio Ch 1 Act 4 cell renewal Video 2 2020 2021
BAB 2 - Sistem Peredaran Darah Manusia/ IPA Kelas 8 #kurikulummerdeka
Hematology | Hematocrit
5.0 / 5 (0 votes)