2. specialised cells

Let's flip it on its head, in this episode we’re going to talk about specialised cells, the differentiated
cells, the cells that do a specific job.
There are six key cells you are going to need to know, so that’s what we are going to focus on today.
In animal cells, those are nerve cells, muscle cells, and sperm cells.
In plants, it’s root hair cells, xylem cells and phloem cells.
When you’re given questions about specific cells, there are two things you need to remember.
I call them the two Fs: function and form.
Basically, what does it need to do? Function. And what has it got to do it? Form.
So today, we’re going to be applying that to just six cells: nerve cells, muscle cells, sperm cells, root
hair cells, xylem cells and phloem cells.
First, nerve cells.
Like your phone or laptop, your body relies on electricity, and it’s the nerve cells that carry electrical
impulses, to transmit signals from your sense organs to your spinal cord and brain, and back to your
muscles or glands.
Signals are passed from one long nerve cell to the next. Think of it like a baton in a relay race passing
from one person to the next.
They send and receive electric signals as messages (or nerve impulses) these go from one nerve cell
to the next, and eventually, to muscles and glands.
If you didn’t have a functioning nervous system, you wouldn’t be able to think, feel, or move, so
they’re very important
How do they work? Well, nerve cells are long. This is so they can be in contact with the brain and
spinal cord and the rest of the body.
They have a main cell body containing ribosomes and the nucleus, and if you can’t remember what
ribosomes do, go back to Episode 1, have a listen and I’ll meet you back here.
Attached to the main cell body are dendrites and a long cable called an axon, covered in a fatty,
myelin sheath to speed up the messages.