Physiological communication is a core concept in IB Sports, Exercise and Health Science (SEHS), yet it is one of the areas where students most commonly lose marks. Many errors occur not because the topic is difficult, but because explanations lack precision, structure, or correct terminology.
Understanding common mistakes helps students write clearer, more accurate answers and avoid unnecessary mark losses in both short-answer and extended-response questions.
Confusing the Nervous and Endocrine Systems
One of the most frequent mistakes is failing to clearly distinguish between the nervous system and the endocrine system.
Common issues include:
- Mixing up electrical impulses and hormones
- Stating that hormones act instantly like nerve signals
- Failing to explain differences in speed and duration
High-scoring answers clearly state that the nervous system uses fast electrical communication, while the endocrine system relies on slower hormonal signalling with longer-lasting effects.
Poor Sequencing of Communication Processes
Another common mistake is describing communication steps in the wrong order. This often appears in questions about muscle contraction or the neuromuscular junction.
Examples of sequencing errors include:
- Mentioning muscle contraction before neurotransmitter release
- Skipping key steps such as action potentials
- Using vague phrases like “signals are sent”
IB examiners reward answers that follow a logical, step-by-step structure from stimulus to response. Clear sequencing demonstrates understanding rather than memorisation.
Overusing General Language
Many students lose marks by relying on general terms instead of IB-specific vocabulary. Words such as “messages,” “signals,” or “instructions” are often used without explanation.
Instead, strong answers include precise terminology such as:
