by Deannah Blackley
Have you ever wondered how your cuts heal? No matter how times you fall over in the park, your skin magically reappears! “How does this happen?” I hear you ask. Well, it’s all thanks to your superhero cells.
Meet my friend Mia, she is just like you. Both of you are made up of 100s of different cell types, each with a different job to do. Some help you run fast like your marvellous muscle cells. Curious cone cells help you to see. You also have immune cells that help to protect your body from evil invaders; the noble neutrophils, the mighty macrophages, and the friendly fibroblasts to name a few. These are very important cells. Mighty macrophages, for example, help to defend your body from evil invaders by eating them whole! The superheroes also help each other by sending homing signals, called cytokines, to alert them of the dangers that lurk ahead. Thanks to cytokine messengers, the superheroes can work together and banish the baddies.
One peaceful afternoon, Mia’s superhero cells were resting when disaster struck; Mia fell from the monkey bars and scraped her knee! It started to bleed. “Quick!” said Captain Collagen, “We must alert the sticky platelets!” This alerted the sticky platelets and they rushed to Mia’s cut and started to stick together. “We’ve got to plug the hole!” cried one platelet, “We can’t let any bad bacteria attack.”
The sticky platelets started to change shape and hold onto each other through the sticky glycoprotein hands on their surface.
“This isn’t working, we’re not sticky enough!” yelled another as they tried to cover Mia’s graze.
“I’ll signal that we need help,” replied the first platelet, releasing cytokine messengers to all the immune cells. Soon after, fibrin glue arrived to help to stick the platelets together and Mia’s cut started to bleed a little less.
Later, the immune cells started to arrive. First on the scene were the noble neutrophils. These cells took care of Mia’s graze for the next two days. “Time to start tidying up,” the neutrophils declared as they arrived. First the noble neutrophils started to release their microbe-destroying powers, antimicrobials, to destroy any bad bacteria or funky fungi who tried to invade the body. Then, the neutrophils started clearing the damage to make room for new cells to grow and called out to the other immune cells by sending more cytokine messengers: “Macrophages! We’re ready for you!”
Day two, the mighty macrophages arrived! “Let’s get to work!” they said, “We need to get Mia’s knee back in tip top condition. Thanks for your hard work neutrophils.”
Then, the neutrophils merged into the macrophages. Their work was done. The mighty macrophages started by finishing the neutrophils’ work to ready the area for rebuilding. Next, the mighty macrophages organised a meeting with the rest of Mia’s knee cells. “Listen up!” called Max the macrophage. “We need to start rebuilding Mia’s knee, so it looks healthy again. Epithelial cells, are you ready?”
Epithelial cells are the cells that make up your skin and they are powerful protectors.
“Yes Max!” replied all the epithelial cells.
“Are you ready to start growing?” asked Max as he and his fellow macrophages sent growth signals to the epithelial cells.
“Of course!” said the epithelial cells. Then, they started to grow larger in size before splitting down the middle to create two cells! This can happen to any cell that needs to grow; it’s called mitosis.
The epithelial cells were left to grow while the mighty macrophages moved onto the support cells. These cells are found under the epithelial cells and they help to provide the epithelial cells all the nutrients they need. “Support cells are you there?” called the mighty macrophages.
“Yes,” said Stella the support cell, “What do you need?”
“The epithelial cells need a new food supply. Can you help them out?” replied Max as the macrophages sent more growth signals to the support cells.
“Right away!” answered Stella and the support cells started to grow just like the epithelial cells.
After all the growth signals were sent, the cells needed something to hold them in place. So, the mighty macrophages started to release a mesh of molecules that help the cells stay in place like the branches on a tree holds the leaves above the ground.
Finally, Max the mighty macrophage called to the friendly fibroblast cells, “Our job is finished. It’s your turn now fibroblasts!” and they sent a homing signal that showed the fibroblast cells where to go. Upon arrival, Frankie Fibroblast went to speak with Captain collagen. “How are things here?” asked Frankie, “Is the repair process going well?”
“It’s been a smooth process so far Frankie. Mia hasn’t picked at her scab this time,” declared Captain Collagen. There was a huge cheer from the surrounding cells.
Usually, Mia would pick at the scab that was trying to heal undoing all the hard work of the superhero cells. This was quite tiring for the superheroes as it would mean that they would have to start all over again. “My collagen brothers and sisters have taken some damage and require repair,” continued Captain Collagen.
“We shall repair them straight away!” replied Frankie Fibroblast, “Let’s get to it fibroblasts!” Immediately, the fibroblast cells began to make fresh collagen and release it where Captain Collagen had suggested. This provides extra strength to the mesh molecules.
Once all the collagen was made, the fibroblasts began to leave. All this time, the epithelial and support cells continued to grow. As more and more of them were made, they started to move across Mia’s cut to cover it up. Soon, the cut was completely covered again, and the scab flaked away without Mia even noticing. Like magic, Mia’s skin had reappeared! The superhero cells went back to their daily activities; ready and waiting for Mia to fall again.
Who knew so many exciting things were happening under your skin?