IGCSE Biology glossary
Effector
Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.
Definition
A muscle or gland that carries out a response when stimulated by a nerve impulse from a motor neurone. Muscles respond by contracting (producing movement) and glands respond by secreting substances such as hormones or enzymes.
What to include in an exam answer
Always state that effectors are muscles OR glands. In reflex arcs, name the specific effector: e.g. Biceps muscle contracts to withdraw the hand, or salivary gland secretes saliva.
Example in context
In a reflex arc, name two types of effector (2 marks): A muscle (which contracts to produce movement) and a gland (which secretes a substance such as a hormone or enzyme).
Related syllabus topic
Coordination & responseRelated terms
- Homeostasis
- Negative feedback
- Tropism
- Reflex arc
- ADH
- Insulin
- Glucagon
- Adrenaline
- Synapse
- Neurone
- Sensory neurone
- Motor neurone
- Relay neurone
- Receptor
- Cornea
- Iris
- Lens
- Retina
- Optic nerve
- Accommodation
- Type 1 diabetes
- Type 2 diabetes
- Hormones
- Endocrine gland
- Auxin
- Thermoregulation
- Vasoconstriction
- Vasodilation
- Sweating