Biology · OCR Paper 1
The Nervous System
How the nervous system detects stimuli and coordinates a response, how a reflex arc works, how the eye focuses light, and how the brain is organised and why damage to the nervous system is hard to treat. Matches OCR GCSE Biology A (Gateway Science) B3.1 (coordination and control: the nervous system). The first two lessons are for both Combined Science and separate Biology. The eye and the brain are for separate Biology only, and the difficulties of studying and treating the brain are for the Higher tier only.
Lessons
Ticks are remembered on this device only.
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1
Neurones and the Nervous System
Your nervous system detects changes around you and inside you and produces a fast, coordinated response. This lesson covers the central nervous system, sensory…
8 terms -
2
Reflex Arcs
A reflex is a very fast, automatic response that protects the body. This lesson explains how the structure of a reflex arc is related to its function, how a…
8 terms -
3
The Eye
The eye is the sense organ that detects light. This lesson is for separate Biology. It covers the main structures of the eye and what they do, how the pupil…
8 terms -
4
The Brain
The brain controls almost everything that you do. This lesson is for separate Biology. It covers the structure and functions of the main regions of the brain…
8 terms
Key terms in this chapter
All 32, gathered from every lesson.
- Neurone
- A nerve cell that carries electrical impulses.
- Stimulus
- A change in the surroundings that can be detected.
- Receptor
- A cell that detects a stimulus and starts an impulse.
- Effector
- A muscle or a gland that carries out a response.
- Central nervous system
- The brain and the spinal cord.
- Synapse
- The gap between two neurones, which neurotransmitters cross.
- Myelin sheath
- A fatty layer round an axon that speeds up the impulse.
- Neurotransmitter
- A chemical that carries the signal across a synapse.
- Reflex action
- A rapid, automatic response that protects the body.
- Reflex arc
- The pathway of neurones involved in a reflex action.
- Relay neurone
- A neurone in the central nervous system that links a sensory and a motor neurone.
- Synapse
- The gap between two neurones.
- Neurotransmitter
- A chemical that crosses a synapse and starts a new impulse.
- Voluntary action
- An action that you choose to do, which involves the brain.
- Reaction time
- The time taken to respond to a stimulus.
- Spinal cord
- A column of nervous tissue that runs inside the backbone.
- Cornea
- The transparent front of the eye that refracts light.
- Iris
- The ring of muscle that controls the size of the pupil.
- Pupil
- The hole in the iris through which light enters.
- Lens
- The flexible structure that focuses light on the retina.
- Retina
- The layer at the back of the eye with the light receptor cells.
- Accommodation
- The change in the shape of the lens to focus on near or distant objects.
- Ciliary muscles
- The muscles that change the shape of the lens.
- Suspensory ligaments
- The fibres that hold the lens and are slack or taut as the ciliary muscles change.
- Cerebrum
- The largest part of the brain, which controls thought, memory, language and voluntary movement.
- Cerebellum
- The part of the brain that coordinates movement and balance.
- Medulla
- The part of the brain that controls the heart rate and breathing.
- Hypothalamus
- The part of the brain that controls body temperature and water balance.
- Pituitary gland
- The gland attached to the hypothalamus that releases hormones.
- Case study
- A detailed study of one person or a small group.
- MRI scan
- A scan that shows which regions of the brain are active.
- Spinal cord
- The column of nervous tissue that joins the brain to the body.