On another note, we don’t really need to exercise all that much, like those white blood cells who have to be fighting every single hour of the day, or those muscles having to stretch and contract A LOT every day.

 

Come join us here in the very top of the entire body! We’re waiting for you! I hope we have convinced you to come join us as a neuron in the brain!

I’m the red blood cell! Some call me an erythrocyte, but you can just call me bloody. I am very important to the body as I help supply other body parts with oxygen, minerals and water! To do this, I am flexible and assume a bell shape as I need to pass through extremely small blood vessels. Isn't this cool? If you become like me, you can be flexible and travel to the most obscure parts to the body!

 

In addition, I never have to feel alone because there are millions of red blood cells that work together with me. Imagine what an awesome army you would be joining. And if you want to live long and prosper, do know that I can live for about 120 days. That is more than the average cell. 

 

So please consider choosing to be a red blood cell!
 
 

Yours sincerely,
 
 

Bloody

Neural cells have lots and lots of dendrites, which can receive or send electrical impulses encoding information. Doesn't it look fun to have so many long arms? Those long bits that come out of the "body" are axons, and the dendrites are connected to the axons. Now, do you see some larger pieces at the back which look stuck together? Those are the myelin sheaths which cover the axon.

The sheath insulates the axon and prevents the electrical impulse from leaking out, increasing the rate of transmission. Doesn't it feel cool to be able to zap impulses to other cells so quickly? Zap! Zap! Zap! Ha!

The red bit in the middle is the nucleus. I expect you know what nuclei do, right? You don't? Okay. They control the processes of the cell and contain the DNA of the cell. Don't tell me you don't know what DNA does. Oh no... Fine. DNA, or deoxyribonucleic acid, is the genetic information for what each cell should look like, do, and basically everything.

Once again, I hope you will become a neural cell like me. Hope to see you soon!

(Muscle cell walks up.)
(Muscle cell to embryo:) Hi, new cell! I see you're very excited to become a specialised cell. But which one to become? Let me give you some advice, be a muscle cell just like me!

THE END

We are also called leukocytes. Our colour may vary, from light purple to pink. We are generally round and flexible. Now, our master needs us. Usually, we patrol around in the bloodstream, but once we hear the warning from affected cells, we immediately race to the battlefield, where we would unleash our full fury on the invaders. We would gobble all the invaders up. Leukocytes have a similar structure to the normal animal cells. Phagocytes have a wonky-shaped nucleus while a lymphocyte has a round one. 

It is very important to be a leukocyte. We protect the body from invaders, When we see enemies, we will FIGHT TO DEATH. It is thanks to our heroic efforts that our master haven’t died by now.

I hope you have learnt something and will join our team!

Oh, so you want to know more about other cells to figure out if you want to turn into them and you would like to know more about me? Okay! 

I am a Cytotoxic T Cell. Cytotoxic T Cells are the special forces of the body! We kill target cells which are cancer cells, cells that are infected by intracellular pathogens (such as viruses or bacteria), or cells that are damaged in other ways directly by inducing apoptosis, which is the programmed killing of the target cell. They release preformed perforins at the target cell surface to generate transmembrane pores that allow entry of foreign substances in the target cell, through which a second set of proteins and granzymes gain entry into the cytosol to initiate an apoptotic series of events (killing the cell).

Although I have cytoplasm, a nucleus, mitochondria, golgi apparatus and endoplasmic reticulum like an animal cell,  I do not have a lysosome, a ribosome or a peroxisome.

This job is very important to this body because we are part of the immune system, which protects the body from invaders, so it is imperative that you become a Cytotoxic T cell.

I hope that I see you again as a Cytotoxic T cell!

The skin structure is made of 3 parts. The top layer is the epidermis, 2nd layer is the dermis and last layer is subcutaneous tissue. Epidermis protects the body from the outside world, keeping the skin hydrated, producing new skin cells and determining the skin color. Dermis protects the body from harm, supporting the epidermis, feeling different sensations and producing sweat and hair. The subcutaneous tissue insulates the body, protecting the body from harm, storing energy and connecting the skin to the muscles and bones.

You should be like me because I am the barrier that keeps out viruses, bacteria and toxins!

I can also communicate with other neural cells and also with other cells through axons and dendrites. The axons may be longer to communicate with more parts of the body. There is also a myelin sheath that helps to increase the speed of communicating through the axons. The dendrites can receive signals from other neurons.

I am important because we can send or receive messages to and from different parts of the body.

I think you will enjoy being a neural cell. I hope you will join me.

A neuron is made up of three basic parts: the cell body, branching dendrites that receive signals from other neurons and the axon, which sends signals out to surrounding neurons through the axon terminal. 
I hope you will consider to be a neural cell.

I am small, round and biconcave. I play a vital role in the circulatory system as I contain haemoglobin which helps to carry oxygen from the lungs or gills to all the body tissues and to carry carbon dioxide to the lungs, where it is excreted. Without red blood cells like me, humans will no longer be able to breathe.

A special adaptation of mine is that I do not have a nucleus, because it allows me to have more haemoglobin, hence allowing me to contain more oxygen. This special function that I have also results in my biconcave structure which helps in diffusion of dissolved nutrients, oxygen and carbon dioxide. 

It is important that you become like me so that together, we can help humans work in the circulatory system. After reading this, I hope you are more willing and will consider to become a red blood cell, just like me.