Medical Central: The Human Body: Cells, Age, and Replacement Tech

Today, read some on the human body, and some of tech that is used (and being trialed and tested) for replacing damaged and not-so-good body parts.

Human Body: Cells, Age, and Replacement Tech
We all know that life is made of cells. Some of us may know that some forms of life, like the bacteria, are made of only one cell. That's the total opposite of human bodies, which have around 10 trillion cells. Yikes! But here's an interesting fact... we all start out life as one cell. Then we grow, and the cells go through mitosis (cell separation) with a special structure inside the body.
The cells aren't all the same... not at all! Cells come in all sorts of different shapes and sizes and functions. Nerve cells have an axon and dendrites which are used to receive and send signals respectively. Smooth muscle cells, which control involuntary muscles and organs (example: stomach), look different and have to "tails" or "tentacles". Sperm cells (an only-male cell) have a tail for swimming around, but they look different and have a different purpose: finding and fertializing (sp?) a female egg cell!
While cells, the basic building materials of life, are different, there are similarities. Cells all have certain structures (and a lot of them) that help them to live. There's one that supplies energy for the cell, some help clear the area of debris, and some help in the mitosis process. The nucleus holds the chromosomes, and the very center of the nucleus controls a lot of it.
There are two main types of chromosomes: the X and the Y chromosome. While both male and females have the X chromosome, only the females double on the X chromosome, while males have a single Y and a single X chromosome. Chromosomes hold DNA. No matter what cell it is, each cells has a basic copy of DNA that's pretty much the same. And each DNA pattern (kind of like the body's plan) is unique and special to each person.
We all know that different ages means different heights, strengths, and so on. There are even certain actions and abilities that are called "milestones" that help keep track of stuff. Telling age can be pretty easy sometimes... the rate of maturity, what one can do, and even the area around the eyes can tell age! But becoming an adult (after puberty) is usually done by age 20. Cells grow and multiply still, but, unlike past years, they're not for growing... they're for replacing the deal cells that show up. And while excersising (sp?) and healthy living and stuff can improve strength and stuff, no one really grows taller after they are 20.
In fact, many old-age problems come from cells not multiplying as much as they used to... Loss of strength comes from less muscle cells, and the famous memory problems come from loss of brain cells.
Now, leaving the cells arena, we come to technology. We covered Medical Imaging for a long while on this blog, and here's some data on some different Medical tech. We know that certain devices can totally replace body parts... some of the most famous are the robotic (and sometimes just artificial) arms and legs. Some of you know pacemakers, which help the heart keep to a beat. And some of you even know about the other-famous hip replacements (total ones include the ball-and-socket joint).
But there are plenty others. Other joints can have replacements... finger, toe, elbow, and knee joints are examples listed in the book. Some replacements are from other humans, like the well-known kidney replacement. But did you know that corneas can be transferred over and replaced too? And hearts can be transferred over from just-dead people (Repeat: JUST dead, not long-time dead!). And skin grafts, while some are man-made (not with natural stuff), are able to come from the same person!
There are even more radical replacements! There are devices to replace damaged brain cells, not-working inner ears (including electrical translator which sends signals into the brain to let it figure out the sound), artificial hearts (apparently being trialed on humans), and there's even an artificial lung being developed for those with diseased and damaged parts of air-filled areas of the body! And even the well-known robotic arm is jumping up in tech a little... some robo-arms have hands that move (at least the fingers)!
But some tech used for helping is old-fashioned, and has been used as long as anyone can remember... for walking, there's a very famous one. It stills exists in the real world, and not just movies and books. It's the good old walking stick! Hey... it pays to stick with what works sometimes, and it's cool that it's still around, despite all the high-tech solutions out there!