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Grey Matter Flashcards

1
Q

Difference between endocrine and nervous system

A

nervous system: acts faster
targets specific parts/cells
has a short lasting effect
electrical impulses sent

Endocrine system: slower but long-lasting
affects through chemical control

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2
Q

What is a phytochrome Which phytochrome in plants is active?

A

Phytochrome absorbs and detects light Pfr is active in plants

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3
Q

What converts Pr to Pfr what converts Pfr to Pr

A

When red light is absorbed by Pr it is converted to Pfr When far-red light is absorbed by Pfr it is converted to Pr

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4
Q

Benefits of plant responses to light

A

ensures that flowering happens at the right time so same species flower at the same time and they flower when insects are available since length of days varies short days in winter and long days in summer

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5
Q

Which phytochrome stimulates flowering?

A

Low levels of Pfr

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6
Q

explain role of neurotransmitters

A

comes from pre-synaptic neurone diffuses across synaptic gap affects post-synaptic neurone

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7
Q

special structure in sensory neurone

A

cell body in middle

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8
Q

how structure of neurone helps conduct impulses

A

Schwann cell convers axon Schwann cell contains myelin which provides insulation So Action potential only occurs at nodes of ranvier (gaps between schwann cells) undergoes saltatory conduction and jumps from node to node

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9
Q

how does structure of axon membrane help with impulses

A

phospholipids restrict ion movement proteins span membrane sodium potassium pump punmps ions across membrane protein gates allow for diffusion of ions

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10
Q

advantages of having mylelinated neurone

A

myelin sheath provides electrical insulation except at nodes of ranvier where neurone is exposed because nodes are site of sodium-gated channel proteins these open when impulse arrives causing depolarisation of nodes impulse jumps from node to node this is known as saltatory conduction only occurs between Schwann cells this is faster than non-myelinated neurones

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11
Q

Why are neurones not affected by a second stimulus that occurs to quickly

A

they are still undergoing action potential neurone hasn’t reached resting potential Sodium ion gates are closed

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12
Q

what are the events leading to depolarisation of membrane

A

depolarisation of adjacent membrane this changes PD across membrane opens sodium gates and sodium ions move into axon

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13
Q

Which type of neurone is found in the central nervous system

A

Relay neurone

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14
Q

direction of impulse in sensory neurone direction of impulse in motor neurone

A

away from receptor towards effector

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15
Q

What is A?
What is B?
What is C?
What is D?

A

A- nucleus

B- Cytoplasm

C- Myelin Sheath

D- Axon

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16
Q

How is an action potential generated?

A

Stimulus occurs
This causes Na+ voltage gated channels to open
Allowing Na+ to diffuse into axon down concentration gradient
More Na+ channels are stimulated to open (positive feedback)
Axon PD becomes positive due to increase of Na+ in axon and is depolarised and AP generated

Wave of depolarisation is passed through axon
Sodium ion gates then close and K+ channels open
K+ permeablility increases
K+ diffuse out down the electrochemical gradient
it repolarises the axon, making it more negative
Hyperpolarisation occurs and K+ channels are closed
Sodium-potassium pump returns axon to resting potential

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17
Q

Events that occur at synapse

A

Impulse arrives at synaptic knob
Ca2+ channels in pre-synaptic membrane open
Ca2+ diffuse into synaptic knob
Synaptic vesicles containng neurotransmitters move towards pre-synaptic membrane
Vesicles fuse with membrane ad neurotransmitter is released into synaptic cleft
Neurotransmitter diffuse across synaptic cleft and
attach to specific protein receptors
on post-synaptic membrane
Na+gated-channels on post-synaptic membrane open
Na+ diffuse in to post-synaptic neurone
PD across mombrane changes and it is depolarised
AP generatedin post-synaptic membrane
Could be spatial or temporal summation
Enzyme breaks down neurotransmitter and it is reabsorned through pre-synaptic membrane
So there is no prolonged stimulation of post-synaptic membrane

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18
Q
A
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19
Q

Difference between spatial and temporary summation

A

Spatial is when potentials from many pre-synaptic neurones cause post-synaptic neurone to reach threshold potential

Temporal is when a single presynaptic neurone fires many times in succession causing postsynpatic neurone to reach threshold potential

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20
Q

Describe structure and role of choroid

A

It is at back of eye, contains black pigment which absorbs all light

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21
Q

Where are Rod Cells found?

Where do neurones of the optic nerve begin?

Which direction is light moving in?

A

C

A

from bottom to top

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22
Q
A
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23
Q

What happens when light hits eye

A

Rhodopsin is bleached
retinal changes shape
and rhodopsin splits into opsin and retinal

24
Q

The cell that links a rod cell to snesory neurone is

A

bipolar neurone

25
How is light observed?
When there is a **light intensity** the light is absorbed by the rod cell retinal changes shape the rhodopsin splits into opsin and retinal opsin binds to cell surface membrane Na+ gated channels *close* Na+ ions are still being *pumped out* Rod becomes *negatively polarised , hypepolarisation* occurs Rod id depolarised and AP is generated
26
How is rhodopsin regenerated after bleaching?
In the dark Na+ *diffuse* back in as gates reopen **ATP** is used to resynthesise rhodopsin
27
Where is rhodopsin located?
In the outer segment inner membrane
28
What do the muscles do to dilate and constrict eyes?
Dilate: radial contract, circular relax Constrict: radial relax, circular constrict
29
How do neurones change pupil size?
Impulse generated Sent through bipolar neurone to sensory neurone and to optic nerve motor neurone receives impulse it is connected to muscles and cause them to contract
30
Biochemistry of habituation
The high frequency of impulses depletes neurotransmitter Calcium ion channels on pre-synaptic membrane become less responsive Post-synaptic membrane is not depolarised Impulses do not reach muscle
31
Benefits to habituation?
Less energy wasted on non-threatening stimuli There are naturally frequent stimuli in animal's habitat (e.g. for underwater it is wave action)
32
Ethics against animal testing
Absolutist view - all use of animals is unacceptable Animals have rights Haven't given consent Will feel pain Causes stress Research topic may not be essential
33
Ethics for Animal testing
Rationalist view - overall good outweighs harm done Few animals as possible being used Welfare of animals being considered
34
A - Medulla B - Temporal Lobe C - Cerebellum D - Occipital Lobe E - Parietal Lobe F - Temporal Lobe G - Hypothalamus H - Pituitary Gland
35
Role of Cerebellum
Maintain balance Co-ordination of movement Muscle movement
36
Role of Medulla Oblongata
Regulate heart rate and ventilation rate
37
Occipital Lobe role
Processes info from eyes Visual center
38
Frontal Lobe role
Decision Making Planing Emtotions Behaviour Includes primary motor cortex (controls most body movements)
39
Role of hypothalamus
controls thermoregulatory centre: monitors body and skin temp initates -ve feedback
40
Parietal Lobe
Orientation Movement Sensation Calculation
41
Temporal Lobe
Processes auditory info
42
Why is MRI better than CT?
MRI has higher image resolution MRI can identify smaller structures than CT MRI uses radio waves, CT uses X-Ray Less risk of damage to tissues with MRI So it can be used more often
43
How does fMRI work?
uses radio waves allows brain activity to be seen in real time active areas have high levels of oxygenation that reflects the signal and is seen as a bright spot
44
What is fMRI used for?
increased flow means increased activity in that part of the brain Study brain activity related to tasks, find which parts of brain required for what
45
How can we analyse CT and MRI scans? How can they be used?
ID location of abnormality Size of abnormality ID type of abnormality Can monitor growth of tumours (or anything else) Can identify any other problems such as accessibilty for surgery
46
What can having eyes closed during critical window do to viual cortex?
Lack of visual stimulation means less impulses to visual cortex so less neurotransmitter released the synapses are weakened neurones are lost lack in connections made in visual cortex occular columns wont develop and are small brain cannot interpret visual information correctly
47
Deine human genome
all the DNA of the human species
48
Ethics of human genome
Insurers might have access to a person's DNA and discriminate Who decides on whether a person gets tested Needs to be confidential Expensive medical treatments might be restricted
49
how genome project aids in drug synthesis
Identifies allele related to disease Drug developed targets this allele So mutant allele can no longer express itself Drug may prevent translation, protein not synthesised drug is more effective than the typical treatments
50
Effect of MDMA on brain
Higher levels of serotonin released reabsorption of serotonin is inhibited in synapse pumps may be reversed to release more serotonin
51
How SSRI works
Serotonin is not reabsorbed SSRI binds to reuptake proteins high level of serotoin remains in synapse Serotonin continues to bind to receptors on post-synaptic membrane and AP still generated
52
How does L-Dopa work
It can pass through blood-brain barrier and enter brain It's converted to dopamine Dopamine triggers action potential at synapses This alleviates symptoms
53
Symptoms of Parkinson's
Stiffness of muscles Tremor of muscles Slowness of movement Lack of balance Walking problems Depression Soeech problems Swallowing problems
54
Describe + Explain Hubel and Weisel's experiment with kittens
Investigated development of visual cortex Closing one eye in kittensto deprive vision for over a period of time led to smaller ocular dominance columns forming in that eye where as the eye that was left open developed large ocular dominance columns there are less impulses fired in neurones in the closed eye this leads to a loss in neurones this suggests that there is a critical period for brain development during which it needs to be stimulated regularly closing the kittens eye before or after the critical period has no effect
55
Describe gene therapy
Use restriction endonuclease to cut out healthy gene Healthy gene inserted in to plasmisd This is then inserted into cells using a vector such as liposomes
56
Why is small sample size bad?
Or else results would not be reliable or valid Conclusion would also be unreliable insufficient data for statistical test
57

Biology (4 decks)

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