They're neurones that carry impulses from the receptors to the CNS
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What do motor neurones do?
They're neurones that carry impulses from the CNS to the effector
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What are receptors and give an example.
Receptors are the cells that detect stimuli e.g. taste receptors on the tongue, retina of the eye covered in light receptor cells
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What are effectors and give an example.
Effectors respond to nervous impulses and bring about a change. 2 types of effectors: muscles & hormone secreting gland
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What is the role of the CNS?
The CNS is a processing centre. It receives information from the receptors & then coordinates a response
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How do neurones transmit information?
When stimulated, neurones transmit information around the body as electrical impulses
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What is an axon?
Axons are made from the nerve cell's cytoplasm stretched out into a long fibre, surrounded by a cell membrane. Electrical impulses pass along it.
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What is the function of the fatty sheath surrounding some axons?
It acts as an electrical insulator, shielding the neurone from neighbouring cells & speeding up the elctrical impulse
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What is a synapse?
The gap between 2 neurones
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Describe how impulses are transmitted across a synapse.
When an electrical impulse reaches the end of the neurone, it triggers the release of transmitter chems. into synapse. They diffuse across gap & bind to receptors molecules on membrane of next neurone
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Describe 1 way ecstasy can increase the concentration of serotonin in the brain.
It blocks sitesin the brain's synapses where serotonin is removed. Because it can't be removed, the concentration increases in the brain= mood enhancing effects
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What is a reflex?
Reflexes are involuntary responses
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Give 2 ways that simple reflexes increase an animal's chance of survival
Sea anemones wave their tentacles more when stimulated by chems. emitted form prey- can catch. Molluscs close their shells when detct predator- not eaten
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Give 3 ways of simple reflexes in humans.
1. muscles in the eye contract making pupil smaller allowing in less light in very bright light 2. If you pick up a hot object- reflex to drop it 3. Knee jerk reflex by tapping under the knee
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How are reflexes modified?
The reflex can be overridden bya neurone between the brain and the motor neurone of the reflex arc
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Briefly describe the experiment carried out by Pavlov on reflexes.
Pavlov noticed that dogs would salivate when smelt food. He rang a bell before he gave food. After, he found that the dogs salivated when bell rang- secondary stimulus= conditioned reflex
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Describe a conditioned reflex.
If a bird has eaten a brightly coloured insect(poisonous)- hates taste. Next time avoids. Associates coulour w/ taste- develop a conditioned reflex to the secondary stimulus
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What happens to pathways when activities are repeated?
When experiences are repeated lots, the pathways that the nerve impulses travel down become strengthened. Strenghtened pathwyas more likely to transmit impulses than others
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Why are complex animals better at adapting to new situations than simple animals?
Complex animals are adaptable becuase of the variety of potential pathways in the brain. Simpler animals have less flexible nervous systems- not as many pathwyas= behaviour more predictable/ less adaptable
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Give 3 methods used by scientists to study the brain.
1. Stdying patients with brain damage 2. Electrically stimulating the brain 3. MRI scans
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What is memory?
Memory is the storage and retrieval of information
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Describe the model of multi-storage memory.
Info you've paid attention to is tem. stored in short-term memory. If repeated enough, transferred to long-term memory otherwise forgotton. Info can be retreived from long-term & remembered
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