Edexcel IGCSE Biology 2.90 reflex arc
Practise reflex arc questions by labelling the withdrawal pathway and explaining why measured response time includes synaptic delays.
- Syllabus
- First assessment 2019
- Course
- Biology 4BI1
Exam points
- Trace impulses from skin receptors through sensory, relay and motor neurones to effectors.
- Identify reflex-arc structures such as receptors, effectors and motor neurones on diagrams.
- Explain why response time includes synapse delays, not just travel along neurones.
2.90 Simple reflex arc question 1
[Maximum number: 4]
Reflexes are responses that protect the body and involve the central nervous system (CNS).
If an animal steps on a sharp object, a reflex arc occurs so that it picks up its foot to prevent further damage.
Describe how named neurones bring about a withdrawal reflex to protect the animal from damage.
A description that makes reference to four of the following points:
- receptor receives / senses / detects (object) / eq
- impulse
- (impulse moves along) sensory neurone to CNS / spinal cord / relay neurone
- (chemical diffusion of) neurotransmitters across synapse
- motor neurone to effector / muscle
- (muscle) contracts
signal /
message
All question bank results loaded