Chapter 6: Control and Coordination

Chapter learning goals: Understand the core concepts, explain key processes, interpret diagrams and apply the ideas to board-style questions.

1. Why coordination is needed

Organisms must detect changes (stimuli) and produce suitable responses. In animals, electrical impulses through neurons provide rapid control while hormones provide chemical coordination, often slower and longer-lasting. Plants lack a nervous system but coordinate growth and movements through chemical signals.

2. Neuron and nerve impulse

A neuron has a cell body, dendrites and a long axon. Dendrites receive information; impulses travel through the cell body and axon to nerve endings. At a synapse, chemicals called neurotransmitters carry the signal across the tiny gap to the next neuron or effector. Myelin insulation speeds impulse conduction in many neurons.