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The nervous system consists of what? and is made up of what? (1)
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Brain Bee Round 1
preparation for the round one of the brain bee. Neuroscience
| Term | Definition |
|---|---|
| How much does a brain weigh? (intro) | 1.5kg |
| The nervous system consists of what? and is made up of what? (1) | brain, spinal cord and peripheral nerves. Made up of neurons and glial cells. |
| What do motor neurons do? (1) | controls the activity of muscles. |
| What do interneurons do? (1) | mediate simple relexes as well as highest functions in the brain. |
| What do glial cells do? (1) | develop the nervous system and important to the adult brain. Used to be thought that they were just supports to neurons. |
| what are the 4 major parts of a neuron? (1) | cell body, axon, dendrite. synapse. |
| What do sensory neurons do? (1) | detect and respond to internal and external environment. |
| the brain stem is divided into three parts - what are they? (1) | hind brain, mid-brain and diencephalon. |
| the diencephalon is divided into two parts - what are they? (1) | the thalamus and the hypothalamus |
| the cerebral hemispheres consist of what? (1) | a core, the basal ganglia and the grey matter of the cerebral cortex. |
| what is the corpus collosum? (1) | a fibrous connection between the left and right hemispheres. |
| Who was the father of modern neuroscience? (1) | Ramon y Cajal. |
| Activity in a neuron is both.... what? (2) | Electrical and chemical. |
| In a neuron, what is polarization? (2) | information only goes in one direction. Dendrite receives, then cell body, then axons transmit. |
| What is a dendritic spine? (2) | These stick out of the dendrites and are where synapses are located. |
| How big is a synaptic gap? (2) | 20 billionths of a metre |
| What do the terms excitation and inhibition describe? (2) | currents that come into the neuron cell (exictation) or flow out (inhibition). the sum of these determines whether a message is passed on or not. |
| What is an action potential? (2) | the transmission of electrical pulses through a neuron. It is an all or nothing event. |
| What does the myelin sheath do? (2) | it insulates the the axon and helps messages to travel faster. |
| What did Alan Hodgkin and Andrew Huxley discover? (2) | Using gian squid, the mechanism of transmission of nerve impulses. |
| What do Schwann cells do? (2) | they insulate the electrical transmission of the nerve from its surroundings. |
| Where are neurotransmitters stored? (3) | In the synaptic vesicles in the endings of the axons |
| The arrival of an action potential leads to the synaptic vesicle opening of what? (3) | ion-channels that let in calcium (Ca++) |
| Once the synaptic vesicles opens, where are their chemical messagers released to? (3) | Into the 20 nanometre synaptic cleft (aka the synaptic gap) where they interact with the receptors of the next neuron. |
| What do glial cells do in the synaptic cleft? (3) | They have transporters, which clear the chemical messengers out of the way before the next action potential comes. |
| The interaction of neurotransmitters with receptors can be described a lock and key. Why? (3) | The attachment of the transmitter (key) to the receptors (lock) opens ion channels, Some are positive (exictatory), some are negative (inhibitory) |
| What is the main excitatory neurotransmitter in the brain? (3) | glutamate |
| What are the main inhibitory synapses? (3) | GABA and glycine. |
| How long does a synaptic transmission take? (3) | 1/1000 of a second |
| Metabotropic receptors are messengers that modulate activity in the neuron. What are they called? (3) | G-proteins. Some common ones are acetylcholine (mental and physical focus), dopamine (happiness), noradrenaline (stress). |
| Which was the first neurotransmitters to be discovered? (3) | Acetylcholine. |
| Drugs interact in different ways with neurons, but they hijack the brains natural systems for pleasure and reward. Which primary chemical messenger do they act on? (4) | dopamine. |
| the effect of alcohol on the brain is....(4) | dampen down excitatory messages and promote inhibition of neural activity. |
| the effect of nicotine on the brain is...(4) | it acts on acetylcholine so it makes the user feel more alert. Very addictive. |
| The effect of cannabis on the the brain is...(4) | control of muscles and regulation of pain. Strong link with schizophrenia. |
| the effect of amphetamines on the brain is...(4) | releases dopamine and serotonin. |
| the effect of heroin on the brain is ... (4) | releases endorphins (pain control) |
| the effect of cocaine on the brain is ...(4) | releases dopamine and serotonin. |
| What are names of the 4 sensory receptors embedded in the dermal layers of the skin? (5) | The 4 types of endings all sense different aspects of touch. Pacinian and Meissner corpuscles sense vibration and flutter, Merkels disks sense pressure and Ruffini endings respond to indentations. |
| What is a receptive field? (5) | The area of skin over which each individual receptor responds. |
| Where do the impulses go after the receptors detect a stimulus? (5) | They go via the relay stations for touch in the medulla and the thalamus to the somatosensory cortex. |
| What is the name of the ‘map’ of the body surface in the cortex? (5) | The homunculus. It has a distorted shape because it reflects the fact that some parts of the body have more receptors than others. |
| What is the two point discrimination test? (5) | It tests the differential sensitivity across the body. |
| How are touch sensors involved in the active control of movement? (5) | They respond to the information that they receive via cross-talk between sensory and motor systems which begin at the first relays in the spinal cord. |
| What is cortical plasticity? (5) | Changes can happen when one part of the body is injured or when it is has had specialised training. the changes are mapped onto the somatosensory cortex. |
| What so A fibres and C fibres do? (5) | They respond to pain in two different ways - A fibres are fast non-myelinated while B fibres are fine, slow and non-myelinated. They have parallel pathways to the cerebral cortex (localisation of pain and emotional aspect of pain) |
| What are the two functions of pain? (5) | (1) to avoid dangerous or threatening situations and (2) to inhibit activity to allow the body to heal after tissue damage. |
| What is the pain mechanism that can be modified to suppress pain? (5) | Endogenous analgesics. Useful in conditions of injury where a person still needs to keep active. |
| What is the pain mechanism that can be modified to enhance pain? (5) | Hyperalgesia. This can be a major problem as chronic pain can increase the intensity or widen the area where it is felt or create pain where there is no cause. It is not widely understood. |
| What are the chemical transmitters involved in making endogenous opioids? (5) | Met-enkaphalin is a type of endorphin and it acts on the same receptors that morphine works on. |
| How does the eye work to turn light into vision? (6) | Enters the eye through the pupil and is focused by the cornea and the lens onto the retina at the back of the eye. The pupil is surrounded by the iris which can expand or contact as light levels vary. |
| What are rods and cones? (6) | They are the 125 million photoreceptors at the back of the retina that detect light. They turn light into electrical signals that get passed to the optic nerve. This is called phototransduction. |
| Orientation selectivity and plasticity are present in the receptive field in the visual cortex. Who discovered this? (6) | David Hubel and Torsten Wiesel won the Nobel Prize for this discovery. |
| What is binocularity? (6) | Each eye sends information that it receives to the visual area of the brain, therefore these cells can respond to an image in either eye. |
| What is blindsight? (6) | A person is not able to see, but can reach for things with accuracy. It reflects possible parallel pathways to parts of the cortex. |
| What does the study of visual illusions tell us? (6) | that there are different kinds of processing going on at different stages of visual analysis. The brain has to interpret motion, colour and shape based on the sensory evidence provided. |
| Give two famous examples of visual illusions that help us understand visual processing. (6) | The Necker cube, the Kanizsa triangle, the Dalmation dog. |
| What is the neuromuscular junction? (7) | a small group of motor neurons whose axons attach to muscle fibres within one muscle. This makes muscles contract and produces force and movement. |
| What are the parts of the brain are involved in controlling movements? (7) | the motor cortex, the premotor cortex, the cerebellum, the basal ganglia and the parietal cortex. |
| What do mirror neurons do? (7) | they are important in imitating and understanding actions. They fire when you are watching someone else perform an action. |
| Where is the motor cortex? (7) | It is a thin strip of tissue that runs across the surface of the brain (where headphones would sit) |
| What is parietal neglect? (7) | when a person fails to notice objects (often on their left side). Often occurs after a stroke. |
| What do the basal ganglia do? (7) | Crucial in the initiation of movements, but it is not clear how. They seem to be a complex filter of information from the cortex. They respond to the neurotransmitter dopamine. |
| What does the cerebellum do? (7) | It makes movements skilful and smooth. |
| What is a common disorder of the motor cortex? (7) | Parkinson's Disease. Causes tremors and difficulty in initiating movements. Caused by the neurons not working in the substantia nigra and not releasing dopamine. |
| What is Purkinje cell? (7) | It is part of the cerebellum and its dendrites have lots of branches (aborisation) in order to receive the many inputs from other parts of the cortex. |
| How many genes in the human genome? (8) | 40,000 |
| Why is the fruit fly Drosophila important to our knowledge of human genes? (8) | Drosophila shares many genes with humans and studies showed the importance of genes in human nervous system development. |
| What other animals have been important to the study of brain development? (8) | zebrafish, frogs, chicks and mice. |
| What is the first step in brain development? (8) | cell division. |
| What is cell differentiation? (8) | individual cells stop dividing and take on specific characteristics - such as neurons or glial cells. This is ordered spatially. |
| what is the neural plate? (8) | It is formed at 3 weeks gestation and is a small group of cells - the front will become the brain and the rear the spinal cord. |
| What is the neural tube? (8) | At 4 weeks gestation, the neural plate rolls up and closes into a tube that is enveloped by the future epidermis. |
| What is spina bifida? (8) | Failure of the neural tube to completely close at the lower end. |
| What is anencephaly? (8) | Failure of the neural tube to completely close at the top end. |
| What is a sonic hedgehog? (8) | a protein that is secreted by the lower end of the neural tube. It induces the expression of the gene that makes a particular type of interneuron. Different concentrations induce other genes |
| What does a growth cone do? (8) | It moves through tissue towards a target. This is known as axonal guidance. Once it gets there, it stops and becomes the synapse. |
| Activity dependent refinement means what? (8) | that the development of neurons has critical periods for development after which the patterns are set. This is determined by electrical activity of the neurons. |
| What are stem cells? (8) | cells that have the potential to change into any sort of cell. They are involved in the research into Parkinson Disease. |
| How many separate sound are there in English? (9) | There are 44 phonemes |
| What proportion of people have dyslexia? (9) | 1 in 10. It is very common. |
| Reading depends on 2 things: being able to recognise alphabetic visual symbols in the right order - This is known as ...?... and it is combined with ..?... (9) | Orthography and phnemic structure. |
| The magnocellular system often does not work properly in dsylexics. What does it do? (9) | This large network of neurons takes visual control of the eye movement system. It has a cucial role in keeping the eyes steadily on each letter in turn. - the motion error signal. |
| What is a phoneme? (9) | It is a letter sound. |
| The ability of the brain to change is called...what? (10) | plasticity. It is where individual neurons are modified for different reasons during development or in response to injury or learning. |
| The use it or lost it principle refers to... what? (10) | The active and actively changing synapses are kept and the inactive ones are pruned (weakened or lost for good). |
| The normal electrical response to chemical transmitters is called the measure of ...(10) | synaptic strength. |
| long lasting changes in synaptic strength (ie learning) can be produced by two kinds of brief neuronal activity known as what? (10) | long term potentiation (LTP) and long-term depression (LTD) |
| Glutamate is released from the synaptic terminals into the synapse and binds to glutamate receptors. The names of these 4 receptors are ? (10) | AMPA, NMDA and kainate and a fourth called mGluR. They all respond to the glutamate but have different functions. |
| The 2 receptors known as the memory molecules are ? (10) | AMPA and NMDA. AMPA fires first and fastest. These stimulate the NMDA to create changes in the synapse. aka = learning. |
Created by:
gayeb