AQA · GCSE · Combined Science
Course version: 8464 · Version from Sept 2018
The human nervous system: Information from receptors passes along cells (neurones) as electrical impulses to the central nervous system (CNS). The CNS is the brain and spinal cord. The CNS coordinates the response of effectors which may be muscles contracting or glands secreting hormones.
Receptors detect a stimulus and generate electrical impulses that travel along neurones to the central nervous system.
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Receptors detect a stimulus and generate electrical impulses that travel along neurones to the central nervous system. The CNS consists of the brain and spinal cord. The brain processes information and coordinates complex responses, while the spinal cord relays information and coordinates many rapid reflex actions. Once the CNS has processed the information, it sends impulses along motor neurones to effectors. An effector is either a muscle, which responds by contracting, or a gland, which responds by secreting hormones or other substances. For example, if the skin detects a sharp object, impulses travel to the spinal cord, which coordinates a muscle contraction to withdraw the hand. This pathway allows rapid, coordinated responses that protect the body and maintain internal conditions.
What earns the marks
- Receptors detect stimuli and initiate electrical impulses.
- Impulses travel along neurones to the central nervous system.
- The CNS is made up of the brain and spinal cord.
- The CNS coordinates responses by sending impulses to effectors.
- Effectors are muscles, which contract, or glands, which secrete hormones.
Common mistakes and how to put them right
Saying the CNS is only the brain.
Put it right: The CNS is the brain and spinal cord.
Stating that glands contract.
Put it right: Glands secrete substances such as hormones, while muscles contract.
Thinking impulses travel along the bloodstream.
Put it right: Impulses travel along neurones as electrical signals.
Exam tips
- Learn the pathway receptor → sensory neurone → CNS → motor neurone → effector.
- When describing an effector, state whether it is a muscle contracting or a gland secreting.
- Use the term electrical impulse rather than message or signal when describing transmission along neurones.
Try the lesson
The start of the The human nervous system: Information from receptors passes along cells (neurones) as electrical impulses to the central nervous system (CNS). The CNS is the brain and spinal cord. The CNS coordinates the response of effectors which may be muscles contracting or glands secreting hormones. lesson, made from checked teaching notes for this specification point.
Have a go first
In what form does information travel along a neurone?
Listen
Receptors detect a stimulus and generate electrical impulses that travel along neurones to the central nervous system. The CNS consists of the brain and spinal cord. The brain processes information and coordinates complex responses, while the spinal cord relays information and coordinates many rapid reflex actions. Once the CNS has processed the information, it sends impulses along motor neurones to effectors. An effector is either a muscle, which responds by contracting, or a gland, which responds by secreting hormones or other substances. For example, if the skin detects a sharp object, impulses travel to the spinal cord, which coordinates a muscle contraction to withdraw the hand. This pathway allows rapid, coordinated responses that protect the body and maintain internal conditions. A strong answer earns marks for these points. Receptors detect stimuli and initiate electrical impulses. Impulses travel along neurones to the central nervous system. The CNS is made up of the brain and spinal cord. The CNS coordinates responses by sending impulses to effectors. A common slip: Saying the CNS is only the brain. Instead, the CNS is the brain and spinal cord. Exam tip: Learn the pathway receptor → sensory neurone → CNS → motor neurone → effector.
See it
Key words
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Neurone transmission
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Central nervous system structure
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Effector responses
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Coordination and control
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See every definition
- Neurone transmission
- Information from receptors passes along cells (neurones) as electrical impulses.
- Central nervous system structure
- The CNS is the brain and spinal cord.
- Effector responses
- The CNS coordinates the response of effectors, which may be muscles contracting or glands secreting hormones.
- Coordination and control
- The CNS coordinates the response of effectors which may be muscles contracting or glands secreting hormones.
Label the diagram
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