Topic 8: Grey Matter Flashcards

Question

How do you prevent a neurone transmission?

Answer 1

drugs that bind to sodium ion channels preventing them from opening, preventing influx of Na+ preventing depolarisation and meaning an action potential cannot be generated.

Answer 2

The gap between adjacent neurones that allow an impulse to be transmitted between neurones.

Answer 3

- synaptic cleft (the gap between adjacent neurones) - presynaptic neurone (the neurone before the synapse, it has a rounded end called the synaptic knob) - post synaptic neurone (neurone after synapse) - vesicles (contain neurotransmitters) - receptor proteins (found of the postsynaptic membrane, which are complementary to a specific neurotransmitters)

Answer 4

1. An action potential arrives at the presynaptic neurone, causing it to depolarise. This depolarisation causes the voltage gated calcium ion channels to open. 2. The calcium ions diffuse into the synaptic knob via calcium ion channels (down concentration gradient). 3. The influx of calcium ion cause the vesicles in the synaptic knob to fuse with the presynaptic membrane and release their neurotransmitters (acetylcholine) through exocytosis. 4. the neurotransmitters diffuse across the synaptic cleft and bind with the complementary receptors molecules on postsynaptic membrane. 5. This causes the associated sodium ion channels to open and sodium ion diffuse into the postsynaptic cell. 6. As a result the postsynaptic neurone will depolarise and an action potential will be generated. 7. the neurotransmitters will then disuse back into presynaptic neurone or will be broken down by enzymes.

Answer 5

- unidirectionality (ensure the one way transmission of impulses) - divergence (one neurone can connect to several other neurones at a synapses allowing never signals to be sent in several directions) - amplification (an impulse does not always cause an impulse to be generated to then next a weak impulse with releases less neurotransmitters meaning less binding onto receptor proteins meaning less voltage as less sodium ions diffusing and less depolarisation meaning an action potential threshold may not be reached)

Answer 6

conjunctiva > thin membrane which cover and protects the front of the eye Sclera > tough connective tissue layer surrounding, protection and maintenance of shape cornea > thick transparent layer that focuses light rates onto the retina iris > pigmented layer containing muscles which contract and dilate the public in order to control the amount go light that enters. lens > stacks of transparent cells which foscu light of retina Ciliary muscles > contract and relax to control the shape of the lens vitreous humous > transparent fluid that maintain pressure and shape retina > contains photoreceptors which absorb lights and generate an impulse through bipolar neurones and optic nerve photoreceptors > contain vesicles containing a light sensitive pigment called rhodopsin which absorb light (cone and rod) Fovea > part of the retina high concentration of cone cell receptors increasing resolution of vision chord > black layer behind the retina which absorbs lights and prevent reflection optic nerve

Answer 7

cone cell > in fovea responsible for coloured visions (3 types: blue, red and green) rod cell > found in peripheral parts of the retina, responsible for monochromatic visions (black and white)

Answer 8

1. Photoreceptors generate action potentials when stimulated by bright enough lights 2. this causes bleaching in which rhodopsin is broken down into opsin and retinal releasing energy. 3. this causes the sodium channels to close and the membrane is no longer permeable to Na+ ions 4. the rod cell will being to hyper-polarise and the release of an inhibitory neurotransmitters will be inhibited. 5. The bipolar neurone can then depolarises and generate an action potential that travels to the brain via the optic nerve

Answer 9

1. Rhodopsin is reformed for opsin and rental with ATP 2. Sodium ions diffuse back down he concentration gradient into the rod cells via sodium channels 3. This causes the rod cell to depolarise 4. triggers the realises of neurotransmitters which diffuse across a synapse to a bipolar neurone, this neurotransmitter inhibits the bipolar neurone being is can depolarise and generate an action potential

Answer 10

These are photoreceptors found in seeds, roots and leaves of plants. They consist of light absorbing pigments and are responsible for co-ordinating plant responses (seed germination and response to environmental cues)

Answer 11

P(R) > The inactive form of phytochrome, it absorbs light from the red part of the spectrum P(FR) > Active phytochrome it absorbs light from the far red part of the spectrum - When PR absorbs red lights is is converted into PFR (during the day) - When PFR absorbs far red light it is converted back into PR - In the absence of red light the PFR gradually converts back into PR (during the night)

Answer 12

1. During the summer days are longer meaning phytochrome exposed to more red light and less far red light meaning PR --> PFR 2. This build up of PFR cause the production of transcription factors which activator light-regulated genes 3. these proteins will produce plant response (germination and plant flowering)

Answer 13

The growth of a plant in response to a directional stimulus. phototropism > growth of a plant in response to the direction of light, plant shoots grow in the direction of light whereas plant root grow away from the light. Geotropism > growth of a plant in response to the direction of gravity. Plant shoot grow away from gravity and plant roots in direction of gravity

Answer 14

IAA is a type of auxin which brings about plant responses (e.g. phototropism) by altering the transcription of genes inside plant cells. It is transported from cells to cell through diffusion and active transport bringing about uneven plant growth.

Answer 15

1. The auxin IAA is produced in plant shoots and root tips 2. directional light causes the redistribution of IAA, transporting it to the shaded/darker side of the plant. 3. In the shoot the higher concentration of IAA on the darker site causes the cells to elongated and stimulate faster growth and the shoot bends towards the source of light 4. In the roots the IAA is transported towards then lower side of the plant roots which inhibit cell elongation 5. This means the lower side grows at a slower rate than the upper side of the roots causing the roots to bend downward

Answer 16

1. receptor cells on organs detect a stimulus (e.g. pancreas detects low blood glucose concentration) 2. effector cells such as glands produce a hormone (glucagon) 3. hormones transported in the blood to where they are needed 4. hormones bring about a response (glucagon converts glycogen into glucose increase blood glucose concentration)

Answer 17

- electrical impulses vs chemical messengers - nervous control faster than hormonal as dependant on speed of blood stream - nervous is a short terms reposes and hormone in long term as broken down slower than neurotransmitters - localised response vs widespread response

Answer 18

Brain is part of the CNS made up of interconnecting neurone. It is made up of different regions that carry out different functions. - cerebrum - hypothalamus - cerebellum - medulla oblongata

Answer 19

This is found in the forebrain and consists of two halves the cerebral hemispheres which control opposite sides of the body. It has a thin outer layer called the cerebral cortex (grey matter) which is highly folded increasing surface area for brain activity. It can then me further divided into frontal, periental, temporal and occipital lobes. It role includes - visons - hearing - speech - thinking - memory

Answer 20

Found in the midbrain. It is responsible for thermoregulation (blood temp), control over sleep, hunger and thirst. It works my monitoring blood flow and releasing hormones itself or stimulate the pituitary gland to realises hormones.

Answer 21

Found as the back of the hindbrain. Responsible for coordinating movement such as balance, coordination and posture.

Answer 22

Responsible for maintaining basic physiological functions such as breathing and blood flow. (cardiac and respiratory centres)

Answer 23

CT scans produce a cross-section images of the brain using X-ray radiation, denser structures show up brighter as they absorb more radiation. This shows the physical structures of the Brian and allows visitation of tissue damage. + allows neurologists to work out which regions not the brain are responsible for which functions - x-rays pontentially carcinogenic

Answer 24

Uses a combination of a magnetic fields and radio waves to generate static cross sectional images off the brain. + Identifys areas of abnormal or damaged tissues (e.g. tumours) - don't indicate brain activity (can't determine the functions) + don't carry health risks associated with x-rays - expensive - interfere with medical devices (pacemakers)

Answer 25

Uses radio waves and magnetic fields to produce a dynamic cross-sectional images of the brain by showing the location of oxygenated blood in the brain, indicating which brain regions are active at one time (measures deoxygenated to oxygenated haemoglobin). - expensive + not associated with x-rays

Answer 26

PET uses radioactive tracers which collect in areas where there is increased blood flow, metabolism or neurotransmitter activity. The tracer in introduced into the blood in advance, and the scanner then detects areas of high radioactivity and thus whether a region is activated to inactive. + indicate real time brain activity - expensive - potential to be carcinogenic

Answer 27

The visual cortex in the region in the cerebral cortex in which visual information is process. After birth the neurones in the visual cortex of babies being to form synapses allowing vial information to be transferred through a processed by the visual cortex. - for neurones to be organised correctly both eyes need to be visually stimulated as synapses the pass nerve impulse are strengthen and become permeant and neurones that don't pass nerve impulses during critical period are losses and cannot be reformed.

Answer 28

An important period in early development of the postnatal visual cortex.

Answer 29

The human Brian is very difficult to study as is easily damaged during surgical examination, different region work together and so cannot be studied in isolation. Some animals have similar brain structure, so findings canoe applied to the human brain.

Answer 30

1. they stitched one of a subjects (moneys and cats) eye closed soon after birth meaning as the animal grew it could only see out of one eye. 2. When the eye was unstitched is was discovered that the eye that had been closed was blind and the ocular dominate columns in the open eye has expanded to take over the the other columns that weren't being stimulated (switched dominance in neurones) 3. The research was then repeated identically on adult mammals 4. they found that once the eye was unstitched that vision fully recovered and no change took place in the distribution of the ocular dominance columns. - showed the importance of the critical period on development of vision

Answer 31

- animals physiologically very similar to humans resulting in numerous breakthroughs in drug and medical research - only carried out when there are no alternative method - regulated by regulatory bodies ensuring their proper care - cell cultures and computer models produce inaccurate results

Answer 32

- small differences in physiologically produces inaccurate results - causes pain and distress to theses animals (unethical) - there are other alternatives (cell cultures and computer models) - animals have a right to life and a right not to be experimented on

Answer 33

A change in the response to a stimulus as a result of repeated exposure over time. It is beneficial as reduces the waste of time, effort and biological resources with a responding to non0threatening and frequent stimulus.

Answer 34

1. repeated exposure to a stimulus over time reduces the number of calcium ion channels in the presynaptic neurones that open resulting in a smaller number of calcium ions influx in the synaptic knob 2. smaller influx of calcium ions causes less vesicle to fuse with presynaptic membrane and release their contents via exocytosis (less neurotransmitters that bind to complementary protein receptors) 3. resulting in a smaller influx of sodium ions into the postsynaptic membrane and less depolarisation 4. this decreases the likelihood of an action potential being generated as threshold potential not reached

Answer 35

chemicals that transmit nerve impulses across synapses.

Answer 36

chemicals that transmit nerve impulses across synapses.

Answer 37

A brain disorder that affects the co-ordination of movement causes by the loss of neurones in some parts of the brain. The lost neurones would have produced the neurotransmitter dopamine (involved in muscle control) - less dopamine released into synaptic cleft meaning less binding to protein receptor on postsynaptic membrane - fewer action potentials generated creating symptoms such as tremors and slow movement

Answer 38

- dopamine agonist (same effects of dopamine by binding to dopamine receptors on postsynaptic neurones) - dopamine precursors (chemicals that can be converted into dopamine in the neurones) - enzyme inhibitors (inhibits that enzymes that would normally break down dopamine) - gene therapy (addition of genes to affected cells) - stem cell therapy (replace lost dopamine producing cells)

Answer 39

A neurological disorder that occurs as a result go a serotonin neurotransmitters (controls mood) deficit in the brain. - less serotonin released in to synaptic cleft, less binding less sodium ions less depolarisation and action potential not generated as threshold potential not reached - reduce the nerve transmissions in parts of the brain that control mood

Answer 40

selective serotonin reuptake inhibitors (SSRIs) > antidepressants that prevent that uptake of serotonin at synapses increasing overall levels of serotonin in the brain Tricyclic antidepressants (TCAs) > increase level of both serotonin and noradrenaline MAOB inhibitors > inhibit enzymes that would usually break down the neurotransmitters

Answer 41

L-dopa is a drug used to treat the symptoms of Parkinson's disease - L-dopa has a very similar structure to dopamine meaning L-dopa crosses the blood brain barrier and is converted into dopamine (catalyst by dopa-decarboxylase) - increases the likelihood of depolarisation and threshold potential generating an action potential - given patients more control over their movement

Answer 42

The development of targeted drugs to treat a variety of human diseases in individual with different genotypes. The drug is test of synthetic tissues which is genetically identical to a patient.

Answer 43

- The human genome project > (involves the sequencing of the entire human genome), the information gathered is stored in a data base and genes that code for certain proteins found an analysed. By knowing the sequences and stature of proteins involved in a disease allow drug to target specific proteins. - genetic screening > allow individuals with a high chance of developing a disease to be know and can implement preventative measures and how they might responds to a specific treatment

Answer 44

- increased research costs (drug companies will just increased price of drugs) - insurance companies and employers may use medical data unfairly to discriminate against individuals. - patient may refuse personalised medicine

Answer 45

a technique used to deliberately modify a specific characteristics of an organisms. This is done by removing a gene from one organisms and transferring it into another organism where the desired gene is then expressed.

Answer 46

1. restriction enzymes used to remove the gene coding for a desired protein from an organisms genome 2. many copies of the gene is made using PCR 3. The copies are then inserted into small loops of DNA called plasmids transferring the copies into microorganisms 4. the genetically modified micro-organisms are grown in larger fermenters enabling them to multiply 5. protein then isolated and purified e.g. human insulin and human blood clotting factors

Answer 47

1. restriction enzymes used to remove the gene coding for a desired protein from an organisms genome 2. many copies of the gene is made using PCR 3. the gene is then inserted into a plasmid and transferred into a bacteria and the bacteria allowed to infect the cell 4. the gene is transferred from the bacteria into the plant nucleus and the plant is stimulated to multiply and grow 5. the protein can then be purified or eaten e.g. human insulin and cholera

Answer 48

1. a gene that code for a protein for the desired protein is injected into the nucleus of a zygote 2. zygote implanted into uterus and develop to become an adult 3. very cell know has the gene to produce this protein as it can be obtained (e.g. milking) e.g. human blood clotting proteins

Answer 49

- Crops can be modified to produce a higher yield and increase nutrition values reduce famine and malnutrition - crops can be modified to be pest resistance - disease can be treated - vaccine can be produced in modified plants making them more accessible - low cost supply of come medication

Answer 50

- Concerns about the Lon term impacts of GM food on human health - poser may develop a resistance - transmission of genetic matters between organisms GM and non GM - Can be very expensive (drug companies)

Answer 51

Brain development is affect by both nature (genetic) and nature (environmental) conditions affecting the growth of the brain and the formation of connection between neurones. The argument is whether nature of nature has the greater influence over brain development (as they interact with each other)

Answer 52

Scientist study the effects that different environments have on the brain development of individuals of the same species. - the environment can be manipulated animals of the same species would have similar genes making it more likely that any difference are due to environmental factors. - genetic modification can be used to switch off certain genes. by raising genetically altered organism with non gm modified impact of genetic factors can be studies

Answer 53

identical twins are genetically identical one raised in different environment, any difference in the brain would be due to nature and similarities nature. - can be compered to non-identical twins

Answer 54

different cultures provide different environmental influences on the brain development of children. - scientist can compare large grouped of children of similar ages from different cultural backgrounds - any diference are more likely be down to nurture rather and nature

Answer 55

- environment outside the womb would not have impacted the brain development of a new born baby. - level of brain development most likely due to nature rather than nature

Answer 56

- environment outside the womb would not have impacted the brain development of a new born baby. - level of brain development most likely due to nature rather than nature

Answer 57

- environment outside the womb would not have impacted the brain development of a new born baby. - level of brain development most likely due to nature rather than nature

Answer 58

- in adult brain damage cannot be easily repaired as brain fully developed, in children scientist can deduce the effect of damage on development - if characteristics (speech, movement) don't develop more likely t be down to nature.