Limits of electrical impulses
Fast, but they cannot reach every cell.
Fast is not enough
Electrical impulses are an excellent way to send a fast message. Yet most living things with many cells use another way too.
What do you think is a limit of electrical impulses?
What this lesson covers
The idea
Electrical impulses are fast but limited: they reach only cells connected by nervous tissue, and a cell needs time to reset before it can generate and transmit a new impulse.
Fast is not enough
Electrical impulses are an excellent way to send a fast message. Yet most living things with many cells use another way too.
What do you think is a limit of electrical impulses?
- They reach only cells connected by nervous tissue
- They are too slow to carry urgent news
- They can reach each and every cell in the body
Impulse or chemical
Sort each feature into the right group.
Two limits
Electrical impulses are fast, but they have two limits. That is why most multicellular organisms also use another means of communication.
Electrical impulses are fast but limited. They reach only cells connected by nervous tissue, and a cell needs time to reset before it can generate and transmit a new impulse.
Notes
Electrical impulses are fast but limited: they reach only cells connected by nervous tissue, and a cell takes time to reset before it can generate and transmit a new impulse.
Check yourself
Which cells can an electrical impulse reach?
What must a cell do after sending an impulse, before it can send a new one?
Why do most multicellular organisms also use chemical communication?
- Only those connected by nervous tissue — correct. Yes!
- Each and every cell in the animal body. Impulses do not reach every cell, only those connected by nervous tissue.
- Only cells that are far from the brain. Distance does not decide it. Impulses reach cells connected by nervous tissue.
- Divide into two cells. The cell resets its mechanisms. The book does not say it divides.
- Take some time to reset its mechanisms — correct. Yes!
- Send the first impulse again at once. A cell cannot continually create and transmit impulses. It needs time to reset.
- Impulses are too slow for fast responses. Electrical impulses are fast. Their limits are reach and the time to reset.
- Chemical signals are faster than impulses. Chemical communication is slower than impulses, but it can reach all cells.
- Impulses reach only connected cells and cells cannot send them continually — correct. Yes!