We all have sense organs which detect changes inside and outside the body. This is not just your five senses, sight, smell, hearing, taste and touch (SSHTT) - but other things like heat and cold, pain etc.
Now then you sensitive person, anything that you are sensitive to is called a stimulus. It stimulates you. You detect the stimulus because your sense organs contain receptor cells. So, back to homeostasis, your skin has receptor cells to detect changes in temperature. Hopefully you have worked out that this leading up to the nervous system.
These receptor cells make electrical signals called impulses. These usually go to the brain, unless it is a reflex action,. The brain then sends impulses to other organs or muscles to make the changes that the body needs to stay the same - back to homeostasis again eh?!
So what happens. Well the electrical impulses travel along neurones (or nerve cells). This movement of impulses is called neurotransmission. This links up nicely to how drugs called stimulants speed up the neurotransmissions. Now if you look at the diagram below, it has a cell body and long extension bits that look like tentacles (but they are not). These are called dendrites and they receive impulses from the receptor cells or other neurones. The impulse then moves along the dendron to the axon. Here it then goes to other neurones and so on.
So, the receptor cells receive the impulse and sends it along the axon. If the receptor cells are damaged no signal is got so no impulse is sent.
So what happens. Well the electrical impulses travel along neurones (or nerve cells). This movement of impulses is called neurotransmission. This links up nicely to how drugs called stimulants speed up the neurotransmissions. Now if you look at the diagram below, it has a cell body and long extension bits that look like tentacles (but they are not). These are called dendrites and they receive impulses from the receptor cells or other neurones. The impulse then moves along the dendron to the axon. Here it then goes to other neurones and so on.
Remember that you are a big organism and there are millions and millions of neurones. Groups or bundles of these neurones are packed together into nerves. We are vertebrates and so we have an organ called the spinal cord. The spinal cord contains many nerves packed together and this connects to the brain. The brain and the spinal cord together make up the central nervous system (CNS) which controls your body.
