| A | B |
|---|
| Sensory neurone | Links receptor to CNS |
| Relay neurone | Joins neurones within CNS |
| Motor neurone | Links CNS to effector |
| Dendrites | Fine branching strutures from nreve cell body |
| Axon | Carry impulses away from nerve cell body |
| Schwann cell | Produce the myelin sheath |
| Myelin sheath | Insulating fatty layer around neurones |
| Nodes of Ranvier | Thin parts of myelin sheath which increase the speed of nerve conduction |
| Resting potential | Potential voltage difference between the inside and outside of the nerve cell membrane in the absence of any stimulation |
| Action potential | An all or nothing reversal of membrane polarity |
| Depolarised | A nerve cell membrane that has been affected by an action potential |
| Refractory period | Period during which an action potential cannot be generated |
| 'All or nothing' Law | The stimulus must exceed the threshold or there is no response |
| Increased diameter of the axon | Speeds up the conduction of a nerve impulse |
| Acetylcholine | A neurotransmitter |
| Cholinesterase | Enzyme that destroys acetylcholine |
| Synapse | Join between 2 neurones |
| Forebrain | Where higher mental activities occur |
| Midbrain | Link between fore and hindbrain |
| Medulla oblongata | Controls vital functions like heart rate and breathing rate |
| Cerebellum | Co-ordinates body movements |
| Hypothalamus | Monitors blood composition and links endocrine and nervous systems |
| Thalamus | Relay station for sensory information |
| Sliding filament theory | How skeletal muscles contract |
| actin and myosin | Make up myofibrils of skeletal muscle |
| Another term for skeletal muscle | Striated muscle |
