B6 - Brain and Mind OCR


Cambridge IGCSE Biology Flashcards on B6 - Brain and Mind OCR, created by franimal on 30/05/2014.
Flashcards by franimal, updated more than 1 year ago
Created by franimal almost 10 years ago

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Question Answer
What is a change in environment called? A stimulus
What is a response to a change in environment called? A behaviour
The pupil has a special reaction to light - what is this called and how does this work? The pupil reflex is the contraction of the pupil in response to light.
What are reflexes that are involuntary and automatic called? Give one example of these in humans, excluding the pupil reflex. A simple reflex - in humans there's gagging.
There are six newborn reflexes - name 3 of them. Stepping, grasping, startle, sucking, rooting and swimming.
Some responses are genetic not learnt, and we just 'know' them. What are these called? Innate reflexes.
What reflex-centered theory do doctors have on why Sudden Infant Death Syndrome occurs? Some babies don't outgrow the reflex to conserve oxygen if smothered by sitting still, so instead of wriggling away the baby can be smothered by his own duvet.
What do receptors do and what two 'kinds' of receptors are there? Receptors are part of the control system, detecting change and passing the information along. There are single receptors such as pain receptors in skin and grouped receptors in complex sense organs such as the eye.
What carries out a response to a stimuli, and what two ways is this done? effector organs that are either glands or muscles, with nervous or hormonal responses respectively
What are the effects of a nervous system response and a hormonal response? Nervous responses are fast, short-term contractions of the muscles whilst hormones are slower but longer term, ranging from adrenaline to growth hormones slow.
What do cells in the nervous system carry that allow different parts of the system to communicate to each other? nerve impulses
What does CNS stand for and in mammals what is it? The Central Nervous System is the brain and spinal cord.
What connects the CNS to the rest of the body? The peripheral nervous system
What are nerves? Bundles of specialized cells called neurons that transmits electrical signals for communication within the body.
In what way are nerve cells very different to most cells and what is this called? The cytoplasm is a very long and thin extension of the cell. It is called the axon.
What is wrapped around an axon and why? (2 reasons) The fatty sheath insulates the axon from other electrical impulses getting mixed up and it increases the speed of the impulses.
What is a reflex arc and what 'parts' are involved? A neuron pathway that brings about a reflex response, with a sensory neuron, then connecting neurons in the the brain or spinal cord, and finally a motor neuron.
What kind of neuron connects the sensory neuron to the appropriate motor neuron in the CNS? A relay neuron.
At what speed do neurons normally travel along the axon? 400 m/s
What are the gaps between neurons called? Synapses.
How do synapses transmit electrical signals? (5 points/facts) 'transmitter substances' diffuse across the gap, and they're the correct shape to fit into the receptor molecules on the membrane of the other neuron, a nerve impulse is stimulated, and the chemical is reabsorbed
What speed do impulses 'travel' across synapses and why does this have a very small effect on the average nerve speed? They travel at just 15m/s but the synapses are just 20nm wide.
Which synapse chemical causes feelings of pleasure when released? serotonin
How do Prozac and Ecstasy work? They stop the re-uptake of serotonin in the brain, so the chemical lingers. This means the serotonin continues to stimulate nerve impulses in the next neuron along.
What is angina and what drug is used to relieve symptoms of it? Angina is severe chest pains caused by the heart getting starved of oxygen, because nerve impulses are telling it to speed up. Beta blockers reduce the transmission of these impulses are regulate the beating of the heart.
What are scientists who investigate the brain called? neuroscientists
What is consciousness and where does it occur in the brain? Consciousness is the part of the human brain concerned with thought and decision making, occurring in the cerebral cortex.
Which surgeon worked with epileptic patients and how did he try to find out more about their brains? Penfield applied electricity to the surface of the brain to see which areas controlled what movements.
What modern technique allows scientists to examine the brain without cutting the skull open, and what are the scans called? MRI or magnetic resonance imaging has proved incredibly useful, and the scans are called functional MRI or fMRI scans.
Which scientist used his dog during an experiment about reflexes and how? Pavlov rang a bell as his dog ate, and over time the dog learnt to salivate even when there was no food, just the bell.
What is a reflex where the response is associated with a secondary stimulus called? A conditioned reflex.
Where are most human reflexes coordinated and which reflexes aren't? Most reflexes are coordinated in the spinal cord, with only the receptors on the head going straight to the brain.
What is conscious control? When a nerve impulse from the brain goes down the spinal cord and stops a reflex from occurring.
Why has communication been so important in giving humans an advantage in survival? Humans could communicate new ideas, such as new tools, but also new threats - a man could see his friend killed by a new predator and warn the whole tribe.
What word describes the connections between neurons? pathways
How do pathways develop? When one neuron first connects to another, it forms the pathway. Every time neuron 1 fires and triggers neuron 2, the pathway develops, till a stimulus for 1 automatically involves 2.
What do gymnasts use that help them memories routines and how does it work? visualizing and repetition - thinking or imagining moving your muscles strengthens the neuron pathways because the neurons are 'fired'
At what age can children no longer learn language and what are wild children called? At around 8 children can no longer learn to speak, and this means feral children can never talk or say more than a few words.
How long does short term memory last in most people and what disease involves severe short-term memory loss? 30-seconds but Alzheimer's disease means the short-term memory area of the brain doesn't work properly and things like the day and simple instructions can't be remembered.
What tests memory? The retrieval of information.
What are explanations of how memory works called and what is the most popular explanation called? There are models of memory such as the multistore model.
What three methods of memorization are there? Repetition (processing again and again), rehearsal (process once and then recount information) and active memory (processing actively such as highlighting).
Which two psychologists argued that the multistore model was too simple and why? Craik and Lockhart showed that if you understand information it's easier to remember, and strong stimulus also work, for example light and colour and sound and smell.
What is the short-term memory now called? An active 'working memory'.
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