- The evolution of multicellular
organisms has led to nervous and hormonal
- Sensor (receptor) cells detect
stimuli and effector cells produce responses
- Nervous systems are made up
of nerve cells (neurones) linking receptor
cells (e.g. in eyes, ears and skin)
to effector cells (in muscles/glands).
humans and other vertebrates the
nervous system is coordinated by
a central nervous system (spinal
cord and brain).
- Nervous systems use
electrical impulses for fast, short-lived
- Hormones are chemicals
that travel in the blood and
bring about slower, longer-lasting
- You must know two examples,
in humans, of nervous and of
and hormonal communication
systems are involved in maintaining
a constant internal environment.
This is called homeostasis.