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level: The Brain, Behaviour and Disease 1

Questions and Answers List

level questions: The Brain, Behaviour and Disease 1

QuestionAnswer
the brainthe main coordinating centre for neural activity it receives info from sense organs, interprets it then transmitts info to effectors
regions of the brainfrontal lobe parietal lobe temporal lobe occipital lobe cerebellum hypothalamus hippocampus medulla oblongata white matter grey matter cortex
frontal lobefound at the front of the brain concerned with decision making, reasoning, planning and consciousness of emotions also involved in forming associations and ideas involves primary motor cortex which stores info about how to carry out different movements
parietal lobefound at the top of the brain concerned with orientation, movement, sensation, calculation and some types of recognition and memory
temporal lobefound at the bottom of the brain concerned with processing auditory info like hearing, sound recognition and speech
occipital lobefound at the back of the brain processes info from the eyes like vision, colour, shape and perception
cerebellumresponsible for balance coordinates movement recieves info from the primary motor cortex constantly checks is the motor programme being used is the right one located near the brain stem
hypothalamuscontrols temp, sleep, hunger and thirst monitors and controls via hormones connected to the pituitary gland located between the thalamus and pituitary gland
hippocampusinvolved in long term memory located deep in the temporal lobe also involved in learning and emotional responses
medulla oblongatacontrol of subconscious heart rate, breathing and blood pressure located in the lowest part of the brain stem
white mattercorpus callosum composed mainly of axons white myelin sheaths give it its characteristic appearance connects the hippocampus, hypothalamus, and other brain structures to the cortex also connects the two hemispheres of the cortex
grey mattercomposed of unmyelinated axons and neuronal cell bodies
cortexsurface of the brain made up of grey matter has left and right hemispheres made up of nerve cell bodies, dendrites and synapses
how do doctors detect problems with the brain?PET CT MRI fMRI
PETpositron emission tomography used to produce detailed images so the brain's structure and function can be evaluated 2D image but can be built up into 3D drawbacks: exposure to radiation, expensive benefits: no risk of X-rays
how do PET help diagnose brain disordersuses isotopes C11,N13 and O15 which are incorported in molecules like glucose or water they are radiotracers patient ingected with radiotracers which decay then emit positrons when the brain is active more O2 and glucose is needed so more blood flows in that region of the brain increases in blood flow are detected by PET as radiotracers are present in that area
CTcomputed tomography uses thousands of narrow beam x-rays rotated around the patient observe structures instead of functions of the brain drawbacks: poor resolution, exposure to x-rays may cause cancer
MRImagnetic resonance imaging uses magnetic field and radio waves to detect soft tissues can diagnose tumors, strokes, brain injuries and infections to the brain and spine excellent resolution 3D benefits: no risk of x-rays, drawbacks: magnetic field may affect pacemaker, takes only a snapshot in time
how do MRI detect problems with the brain?high frequency waves and magnetic field cause the direction and frequency of hydrogen nuclei spin to change this takes energy from the radio waves radio waves are turned off and the hydrogen nuclei return to their original alignment releasing the energy they absorbed this energy is detected then a signal is sent to the computer which analyses it to produce an image
fMRIfunctional magnetic resonance imaging provides imaging of the brain whilst in action follows the uptake of oxygen in active brain areas this is possible as deoxyhaemoglobin absorbs the radio wave whilst oxyhaemoglobin does not benefits: no x-rays drawbacks: expensive, patient must be conscious
how does fMRI work?when a part of the brain is used that means there is more blood flow therefore more blood flow means more oxygen so more oxyhaemoglabin this means there is less absorption of the radio waves the less absorption of radio waves means that part of the brain is really active and this will show up on the screen
define ethicsrefer to the rules provided by an external source
define moralsrefer to an individuals own principles regarding right and wrong
what are the four ethical frameworks?rights and duties maximising the amount of good in the world making decisions for yourself leading a virtuous life
what are the conditions on using animals in research?consider the animal's welfare for normal behaviour, health, food and water only use as few animals as possible use invertebrates as much as possible the animal cannot be endangered like the great ape or orangutan
abolitionist vs utilitarianismabolitionist argue that animals can't give consent so it is never ok to use them utilitarians argue that if it is for the greater good then it is fine to use them as long as they follow the conditions for using animals in research
habituationa type of learning gives animals the ability to ignore unimportant repetitive stimuli so that the limited sensory, attention and memory resources can be concentrated on more rewarding or threatening stimuli does not alter the sensory system
how do animals become habituated to stimuli?stimulus is applied impulse passes along the sensory neurone which synapses with the motor neurone the motor neurone passes the impulse to the effector causing a muscle to contract or gland to secrete with repeated stimulus the Ca2+ channels of the sensory neurone become less responsive to changes in voltage so less neurotransmitters are released so less Na+ enter the motor neurone no action potential generated in motor neurone and no impulse is passed on to the effectors the animal has become habituated to the stimulus
investigate habituation to a stimulus in snailsdampen a cotton bud with water firmly touch the snail between the eye stalks with the dampened cotton bud and immediately start the stopwatch measure the length of time it takes for the snails eye stalks to reemerge repeat this until the snails eye stalks stop retracting record the results and carry out repeats to get a mean
what is dopamine?neurotransmitter secreted by hormones promotes reward motivated behaviour when dopamine levels are too low it can cause Parkinson's disease when dopamine levels are too high it can cause schizophrenia
symptoms of Parkinson's diseasestiffness of muscles tremor of muscles slow movement poor balance walking problems
treatments of Parkinson's diseaseselegiline - MAO inhibitor - stops MAO enzyme breaking down dopamine L-dopa - dopamine precursor that can enter the brain via the bloodstream dopamine agonist - mimic dopamine by binding to its receptors, reduces risk of side effects of high dopamine levels DBS - deep brain stimulation, surgery which treats the symptoms reduces risk of side effects of high dopamine levels
what is serotonin?neurotransmitter involved in determining someone's mood
symptoms of depressionfeelings of sadness, anxiety and hopelessness can go on for weeks and months loss of interest in probable activities, reduced energy levels, insomnia, thoughts of death
treatments for depressionMAOI's - they break down serotonin so they are rarely used due to adverse side effects SSRI - selective serotonin reuptake inhibitors, increases serotonin level blocks the reuptake of serotonin from the synaptic cleft
why can't dopamine be given exogenously?dopamine can't enter the brain via the bloodstream