Chemical communication by hormones
A chemical that spreads to every cell.
Spreading the news
Imagine one cell wants to tell many cells something. It cannot send an impulse to cells that are not connected by nerves.
What could the stimulated cell do instead?
What this lesson covers
The idea
In chemical communication, stimulated cells release a compound (a hormone) that diffuses around and is detected by special molecules on other cells' surfaces; it is slower than impulses but reaches all cells, steadily and persistently.
Spreading the news
Imagine one cell wants to tell many cells something. It cannot send an impulse to cells that are not connected by nerves.
What could the stimulated cell do instead?
- Release a chemical that spreads around
- Send a bigger electrical impulse
- Wait until the cells move closer
Follow the chemical
Press Next step. The red cell is stimulated.
A slower, wider message
A hormone is a chemical message. Cells need detectors on their surfaces to read it. It is slower than an impulse, but it reaches cells that nerves do not.
In chemical communication, stimulated cells release a compound, a hormone, that diffuses around and is detected by special molecules on other cells' surfaces. It is slower than impulses but can reach all cells, steadily and persistently.
Notes
Stimulated cells release a hormone that diffuses around and is detected by special molecules on other cells' surfaces. It is slower than impulses but reaches all cells, steadily and persistently.
Check yourself
What does a stimulated cell release in chemical communication?
How do other cells detect the hormone?
How does chemical communication compare with electrical impulses?
- A chemical compound, a hormone — correct. Yes!
- An electrical impulse. Chemical communication works instead of generating an electrical impulse.
- A new muscle cell. The cell releases a chemical compound. It does not make a muscle cell.
- With their nuclei. The book says other cells detect the compound with special molecules on their surfaces.
- With special molecules on their surfaces — correct. Yes!
- With nerve fibres joined to them. Chemical signals reach cells regardless of nervous connections.
- It is faster and reaches only a few cells. Chemical communication is slower than impulses, and it can reach all cells.
- It is as fast and needs nervous tissue. It is slower, and it does not depend on nervous connections.
- It is slower but can reach all cells, steadily and persistently — correct. Yes!