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Biology 21st century > Brain and mind > Flashcards

Flashcards in Brain and mind Deck (131)
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1
Q

Why do multicellular organisms need communication systems?

A

So that the body works as a whole

2
Q

What are the two communication systems?

A

Nervous system, hormone system.

3
Q

What are the organs that make up the nervous system?

A

Brain and spinal cord.

4
Q

What sort of response is produced by the nervous system?

A

A quick and short response.

5
Q

What sort of response is produced by the hormone system?

A

A slower response, but longer lasting.

6
Q

In vertebrates, what does the CNS (central nervous system) consist of?

A

Brain and spinal cord.

7
Q

In mammals, what is the CNS connected to?

A

The PNS (peripheral nervous system).

8
Q

What does periphery mean?

A

The outskirts, or edges; the external boundary

9
Q

What is the PNS made up of?

A

Neurons.

10
Q

What would you call a neuron that is detecting changes in the environment?

A

A sensory neuron.

11
Q

What would you call a neuron that is responsible for communicating a response?

A

A motor neuron

12
Q

What do sensory neurons connect?

A

A receptor (eg in the eye) with the CNS

13
Q

What do motor neurons connect?

A

The CNS to effectors.

14
Q

What is the name given to changes in the environment that are detected by an organism?

A

Stimuli

15
Q

What are hormones?

A

Chemical messengers

16
Q

Where are animal hormones produced?

A

In glands

17
Q

How are hormones transported?

A

In the bloodstream

18
Q

How do hormones only affect the target cells?

A

The genes controlling the proteins required for the response are switched off in other cells.

19
Q

Where is insulin produced?

A

The pancreas.

20
Q

What is controlled by the use of insulin?

A

Blood sugar

21
Q

How does insulin act on body cells?

A

It enables them to take in glucose from the blood.

22
Q

Where is oestrogen produced?

A

Ovaries (and a little in the testes)

23
Q

What does oestrogen do during puberty?

A

It controls the development of secondary sexual characteristics, eg breasts, body shape.

24
Q

What does oestrogen do in all women?

A

Controls the menstrual cycle

25
Q

What sort of messages does the nervous system send?

A

Electrical

26
Q

What sort of messages does the hormonal system send?

A

Chemical

27
Q

What are neurons specialised to do?

A

Carry nerve impulses

28
Q

What is the shape of a neuron?

A

Looooooooooooooooooooooooooooooong

29
Q

What do neurons consist of?

A

A cell body, that contains the nucleus, and the long axon. It also has branches on the cell body called dendrites.

30
Q

Where would you find the longest axon?

A

In the blue whale, running from tail to brain, so about 25 metres.

31
Q

What is the direction of the impulse along the axon?

A

It runs away from the cell body

32
Q

What is the axon a long extension of?

A

The cytoplasm

33
Q

What are some axons covered in?

A

A myelin sheath.

34
Q

What is the speed of nerve impulse affected by?

A

Temperature; diameter of the axon; the myelin sheath

35
Q

How does temperature affect the speed of nerve impulses?

A

It is faster in warm blooded animals than cold blooded animals.

36
Q

How does the diameter of the axon affect the speed of nerve impulses?

A

It is faster as the diameter goes up.

37
Q

How does the myelin sheath affect the speed of nerve impulses?

A

It speeds the nerve impulse up as it “jumps” from gap to gap.

38
Q

What does the myelin sheath do, apart from speeding the nerve impulse up?

A

It insulates the neuron from neighbouring cell.

39
Q

What is there between two neurones who want to have a little gossip?

A

A small gap called the synapse.

40
Q

What happens when the electrical nerve impulse gets to the end of the axon?

A

It is changed to a chemical signal.

41
Q

What happens when the chemical signal has crossed the synapse?

A

It is changed to an electrical signal.

42
Q

How many synapses per neuron?

A

There can be many, so one neurone can communicate with many neurons.

43
Q

What is the chemical that crosses the synapse called?

A

The transmitter substance.

44
Q

What happens when the transmitter substances is released into the synapse?

A

It diffuses across the gap, and then binds with receptor molecules on the the neuron.

45
Q

What happens to the transmitter substance after the next neuron has sent the electrical impulse?

A

It is either taken back up by the neuron, or broken down by enzymes.

46
Q

Why is there more than one type of transmitter molecule?

A

They work on different nervous pathways.

47
Q

Name a transmitter molecule that is important in the brain

A

Serotonin

48
Q

Some transmitters do not work by exciting the next nerve. What else can they do?

A

They can inhibit the next nerve, or work on muscles instead of nerves.

49
Q

How many different transmitters fit one receptor?

A

One - again, lock and key idea.

50
Q

What does the nervous system respond to?

A

Stimuli (one stimulus)

51
Q

Stimuli are detected by?

A

Receptors

52
Q

How can receptors be organised?

A

They can be part of organs, or organised into groups, or spread over large areas.

53
Q

What coordinates the response to a specific stimulus?

A

The CNS

54
Q

What is the response to a stimulus made by?

A

An effector

55
Q

What effectors are there?

A

eg glands; muscles

56
Q

What do glands do?

A

Release chemicals such as hormones and enzymes.

57
Q

When is the hormone insulin released?

A

After eating, when blood sugar rises.

58
Q

What do we use muscles for?

A

Movement

59
Q

On a basic level, what movement does an organism need to do?

A

It needs to move away from dangerous, unpleasant stimuli and towards pleasant ones (eg food).

60
Q

Do any of our muscles move in ways that we can’t control?

A

Yes, eg the heart, the gut walls, the muscles associated with breathing, the bladder

61
Q

What is a reflex?

A

A simple response to a stimulus

62
Q

Give an example of a reflex.

A

eg Dropping a hot cup of tea.

63
Q

What is the pathway of a reflex through the nervous system called?

A

Reflex arc

64
Q

The reflex arc is?

A

stimulus->receptor->sensory neuron->relay neuron in CNS->motor neuron->effector (often muscle)

65
Q

When would you learn a simple reflex?

A

You don’t, they are present from birth

66
Q

Why do we have reflexes?

A

They enable us to respond quickly to stimuli that could harm us.

67
Q

Name some of your reflexes

A

dropping a hot object, the knee jerk reflex, the pupil reflex

68
Q

What is the pupil reflex?

A

Pupils contract when light is shone into them

69
Q

How many reflexes does the human baby have, compared to the adult?

A

More

70
Q

Name some new born reflexes

A

Stepping (the baby walks when held upright), grasping (if you put something against the palm of the babies hand); sucking (when something is placed in the babies mouth).

71
Q

Why are reflexes rapid?

A

If the stimulus is below the neck the brain is not involved at all, only the relay neurons in the CNS).

72
Q

What do the relay neurons connect to, as well as the reflex arc?

A

Neurones that run to the brain.

73
Q

What do the relay neurons’ connection to the brain permit us to do?

A

To know about the reflex action; to inhibit the reflex action if we anticipate it.

74
Q

Why can we only inhibit a reflex action if we anticipate it?

A

The brain will only find out after the reflex has occurred, due to the speed of the reflex.

75
Q

What name is given to the ways that an animal acts?

A

Behaviours

76
Q

How does an animal acquire behaviours?

A

They can be instinctive, or learned.

77
Q

Instinctive behaviours are controlled by…

A

reflex responses.

78
Q

Can simple animals learn?

A

Very simple animals can’t - however, even insects can.

79
Q

How can an animal gain a reflex response to a stimulus?

A

Conditioning. (Learning, effectively)

80
Q

Give examples of conditioning

A

Pavlov’s dogs, John B Watson’s study with eight month old Albert.

81
Q

What was the conditioning shown by Pavlov’s dogs?

A

After learning to associate the sound of a bell with food, they started salivating at the sound of the bell even without food.

82
Q

What was the conditioning shown by Albert?

A

He learned to fear a rat because a loud noise was associated with it. Note - this sort of reflex does go through the brain.

83
Q

With Pavlov’s dogs, what is the name given to the bell?

A

It is the secondary stimulus.

84
Q

What is the value of a conditioned reflex?

A

It has survival value, in that the animal does not need to think about what to do, it responds quickly. eg - a small gnu learns to associate the sight of a lion with the panic of the herd (unpleasant) so will avoid the lion in future.

85
Q

When an animal is sick after eating, what happens?

A

It develops a conditioned reflex against eating that type of food, as it might well have been the food that made it ill. (Raisins, anyone?)

86
Q

Why do we believe that our brain gave us an advantage?

A

It enables social behaviour; it enables learning by experience, so we are able to exploit new situations.

87
Q

What is the thin outer layer of the brain called?

A

The cerebral cortex.

88
Q

What is the cerebral cortex involved with?

A

Intelligence; memory; language; consciousness.

89
Q

Why is the cerebral cortex folded?

A

To get more of it into the space allowed by the skull.

90
Q

Who maps the brain?

A

Neuroscientists

91
Q

How do neuroscientists map the brain?

A

Using invasive, and non-invasive techniques.

92
Q

what invasive techniques can be used to map the brain?

A

Observation when a specific part of the brain is damaged; during brain surgery, using electrodes to stimulate the brain and having the patient say what is experienced.

93
Q

What non-invasive techniques are there for mapping the brain?

A

eg MRI scans, PET scans. Used for comparing diseased brains with normal brains; looking at the brain when it is stimulated by music, language, etc.

94
Q

How do we learn?

A

By forming new paths between neurons (so old pathways may be lost); certain pathways are more likely to be used than others.

95
Q

What is a pathway formed by learning called?

A

A neuron pathway.

96
Q

If an experience is repeated, what happens to the neuron pathway?

A

It is strengthened.

97
Q

How else can neuron pathways be strengthened?

A

By using strong stimuli, eg smell, colour

98
Q

How does practise improve our ability to do things?

A

The neuron pathway is strengthened.

99
Q

Who forms neuron pathways more easily, children or adults?

A

Children

100
Q

How many neurons in our brains?

A

Billions, so the possible number of inter-connections is huge!

101
Q

What happens to the new-born reflexes?

A

They are lost as we learn new behaviours.

102
Q

What happens if a child is not given appropriate stimuli?

A

They may not progress in their learning.

103
Q

What does evidence suggest about the ability to learn things, as related to age?

A

Some skills can only be learned at a certain age, eg language.

104
Q

What evidence do we have about a “window of opportunity” with language development?

A

Feral children will learn only very limited language when returned to civilisation (but it does depend on how much language they had when they went feral).

105
Q

What is memory?

A

A way of storing, and retrieving, information. Guaranteed to fail in an exam.

106
Q

What are the two types of memory?

A

Short term and long term memory

107
Q

How is it easier to remember information?

A

If there is a pattern; if you repeat it; if you add a strong stimulus.

108
Q

What is long term memory?

A

The experiences we have that are stored for a long time

109
Q

What is short term memory?

A

The things we are remembering from now, like a phone number, which may be forgotten.

110
Q

How can we explain how memory works?

A

We try to use models of how we think it works.

111
Q

What is the multi-store model of memory?

A

Sensory memory; short term memory; long term memory.

112
Q

Where does an initial stimulus go, in the multi-store model of memory?

A

Into the sensory memory.

113
Q

Where does an initial stimulus go after the sensory memory, in the multi-store model of memory?

A

Into the short term memory

114
Q

Where does an initial stimulus go after the short term memory, in the multi-store model of memory?

A

Into the long term memory

115
Q

What makes the initial stimulus move on from the sensory memory, in the multi-store model of memory?

A

Paying attention to the stimulus

116
Q

What makes the initial stimulus move on from the short term memory, in the multi-store model of memory?

A

Rehearsal

117
Q

How long does the sensory memory last, in the multi-store model of memory?

A

1-3 seconds

118
Q

How long does the short term memory last, in the multi-store model of memory?

A

15-30 seconds

119
Q

How long does the long term memory last, in the multi-store model of memory?

A

1 second-lifetime.

120
Q

What happens if a memory arrives in a memory store, and it is not passed on, or retrieved (in the multi-store model of memory)?

A

It is forgotten

121
Q

Why are models not very good for explaining memory?

A

Memory is more complicated than the model; no model really explain how long term memory works; the multi-store model is too linear; the multi-store model does not sub-divide short and long term memory; the model does not differentiate between different stimuli, or different people

122
Q

How do many drugs and toxins work on the nervous system?

A

Affecting the transmission of impulses across the synapse; stopping the transmission; changing the speed of the transmission; or making the impulse stronger or weaker.

123
Q

What does the anti-depressant Prozac do?

A

It increases the levels of the transmitter substance serotonin.

124
Q

What does Ecstacy (MDMA) do?

A

It increases the levels of serotonin released.

125
Q

Why do people feel “down” after ecstacy?

A

The brain’s serotonin is depleted, so the person feels tired and irritable.

126
Q

What should happen to the transmitter molecules after the transmission of a nerve impulse?

A

They should be removed from the synapse.

127
Q

What does MDMA do to the sites on the neuron where serotonin would be reabsorbed?

A

It blocks them.

128
Q

What does MDMA do to the concentration of serotonin in the synapse by blocking the reabsorption sites?

A

It increases it in the synapse, giving a feeling of well-being, but it also means that the neurones are depleted of serotonin for use later..

129
Q

What does curare, the South American Indian arrow poison, so?

A

It blocks a transmitter molecule that is used for movement. A version is used to stop the body moving during surgery.

130
Q

What are beta blockers?

A

A prescription drug that blocks the transmitter molecule adrenaline. They can reduce anxiety, which is why BG don’t allow them.

131
Q

What do the opiates do?

A

They mimic the effects of some neurotransmitters.