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The human nervous system
Study how the nervous system detects stimuli, coordinates rapid responses, protects the body through reflex actions and controls specialised organs.
43
Objectives
10
Flashcards
10
Questions
90 min
Study time
AqaGcseBiologyHomeostasis and response
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Syllabus checklist
What you need to know
43 objective pages available
Structure and function13 objectives
- Describe the nervous system as a system that enables humans to react to their surroundings and coordinate behaviour.
- Describe the pathway in which receptor cells detect stimuli, sensory neurones carry impulses to the CNS, the CNS coordinates a response and motor neurones carry impulses to effectors.
- Explain that the brain and spinal cord form the central nervous system.
- Describe muscles and glands as effectors that bring about responses, with muscles contracting and glands secreting hormones.
- Explain why reflex actions are automatic and rapid protective responses that do not require conscious thought.
- Describe a reflex arc using the sequence stimulus, receptor, sensory neurone, relay neurone, motor neurone and effector.
- Explain the role of synapses between neurones in transmitting signals across gaps.
- Use a reflex arc diagram to identify sensory, relay and motor neurones.
- Explain how the nervous system enables rapid communication compared with hormonal coordination.
- Interpret data from nervous-system experiments, including reaction-time data.
- Translate reaction-time information between numerical and graphical forms.
- Carry out Required Practical 7 by planning and performing an investigation into the effect of a factor on human reaction time.
- Apply safe and valid practical design to reaction-time investigations, including control variables, repeats and calculation of mean values.
The brain (biology only)8 objectives
- Describe the brain as an organ made of billions of interconnected neurones that controls complex behaviour.
- Identify the cerebral cortex as the brain region associated with consciousness, intelligence, memory and language.
- Identify the cerebellum as the brain region associated with coordinating muscular activity and balance.
- Identify the medulla as the brain region associated with unconscious activities such as breathing and heart rate.
- Explain why investigating and treating brain disorders is difficult because the brain is complex and delicate.
- Explain (HT only) how brain function can be studied by examining patients with brain damage.
- Explain (HT only) how brain function can be studied using electrical stimulation and MRI scanning.
- Evaluate (HT only) the benefits and risks of procedures carried out on the brain and nervous system.
The eye (biology only)14 objectives
- Identify the retina, optic nerve, sclera, cornea, iris, ciliary muscles, suspensory ligaments and lens in the eye.
- Describe the retina as the light-sensitive layer containing receptor cells sensitive to light intensity and colour.
- Describe the optic nerve as the structure that carries impulses from the eye to the brain.
- Describe the sclera as the tough supporting outer layer of the eye.
- Describe the cornea as a transparent outer region that refracts light entering the eye.
- Describe the iris as the coloured part of the eye that controls the diameter of the pupil.
- Explain how ciliary muscles and suspensory ligaments change the shape of the lens during accommodation.
- Describe accommodation for near objects, where ciliary muscles contract, suspensory ligaments loosen and the lens becomes thicker.
- Describe accommodation for distant objects, where ciliary muscles relax, suspensory ligaments tighten and the lens becomes thinner.
- Explain that myopia, or short sightedness, is caused when distant objects are focused in front of the retina.
- Explain that hyperopia, or long sightedness, is caused when near objects are focused behind the retina.
- Describe how spectacle lenses correct myopia and hyperopia by changing the refraction of light before it enters the eye.
- Interpret ray diagrams showing myopia, hyperopia and their correction.
- Evaluate the use of contact lenses, laser surgery and replacement lens surgery to correct vision defects.
Control of body temperature (biology only)8 objectives
- Describe body temperature as an internal condition monitored and controlled by the thermoregulatory centre in the brain.
- Explain that the thermoregulatory centre contains receptors sensitive to the temperature of the blood.
- Explain that temperature receptors in the skin send impulses to the thermoregulatory centre.
- Describe vasodilation and sweating as responses when body temperature is too high.
- Describe vasoconstriction, reduced sweating and shivering as responses when body temperature is too low.
- Explain (HT only) how vasodilation and sweating help lower body temperature.
- Explain (HT only) how vasoconstriction and shivering help raise body temperature.
- Apply thermoregulation knowledge to unfamiliar contexts involving heat transfer between the body and surroundings.
Key terms
nervous systemcoordinationsensory neuronemotor neuronecentral nervous systemspinal cordeffectorsglandsreflex actionautomatic responsereflex arcsynapse
Exam tips
- Understand the Nervous System's Role: Remember to create a mind map that outlines the components of the nervous system and their functions in reacting to stimuli and coordinating behavior. Link your answer to Structure and function in The human nervous system, and keep the biology specific to nervous system.
- Understand the Pathway of Nerve Impulses: Remember to create a flowchart that outlines the pathway from receptor cells detecting stimuli to the effectors responding, including sensory neurones, the CNS, and motor neurones. Link your answer to Structure and function in The human nervous system, and keep the biology specific to effectors.
Common mistakes
- Misunderstanding the Role of the Nervous System: Students should emphasize that the nervous system not only consists of nerves but also processes information from stimuli and coordinates appropriate responses to enable behavior.
- Misunderstanding the Pathway: To fix this, students should create a flowchart that clearly outlines the sequence: receptor cells detect stimuli, sensory neurones carry impulses to the CNS, the CNS coordinates a response, and motor neurones carry impulses to effectors.
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