B1.2 Nerves and hormones Flashcards

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1
Q

The nervous system enables humans to

A

React to their surroundings and coordinate their behaviour

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2
Q

Stimulus

A

Change in environment

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3
Q

Receptors detect

A

Stimuli

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4
Q

Receptors in the eyes are sensitive to

A

Light

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5
Q

Receptors in the ears are sensitive to

A

Sounds and changes in position, enable us to keep our balance

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6
Q

Receptors on the tongue are sensitive to

A

Chemicals which enable us to taste

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7
Q

Receptors in the nose are sensitive to

A

Chemicals which enable us to smell

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8
Q

Receptors in the skin are sensitive to

A

Touch, pressure, pain and temperature changes

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9
Q

Light receptor cells have a

A

Nucleus, cytoplasm and cell membrane

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10
Q

A stimulus can be

A

Light, sound, touch, pressure, pain, chemical or a change in position or temperature

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11
Q

The central nervous system consists of

A

The brain and the spinal cord

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12
Q

Neurones transmit information as

A

Electrical Impulses

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13
Q

Sensory neurones

A

Nerve cells that carry signals as electrical impulses from the receptors to the central nervous system

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14
Q

Relay neurones

A

Nerve cells that carry signals from sensory neurones to motor neurones

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15
Q

Motor neurones

A

Nerve cells that carry signals from the central nervous system to the effector muscles or glands

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16
Q

Effectors - muscles

A

Contract in response to a nervous impulse

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17
Q

Effectors - glands

A

Secrete hormones as a response to a nervous impulse

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18
Q

Reflex actions are

A

Automatic and rapid

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19
Q

First stage of a simple reflex action

A

A receptor detects a stimuli. Impulses are sent from the receptor along a sensory neurone to the central nervous system

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20
Q

Second stage of a simple reflex action

A

At a synapse between a sensory neurone and a relay neurone in the central nervous system, a chemical is released that causes an impulse to be sent along a relay neurone

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21
Q

Third stage of a simple reflex action

A

A chemical is then released at the synapse between a relay neurone and motor neurone in the central nervous system, causing impulses to be sent along a motor neurone to the effector that brings about the response

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22
Q

Fourth stage of a simple reflex action

A

The effector (either a muscle or a gland) responds by contracting or by secreting chemical substances

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23
Q

Synapse

A

The connection between two neurones. The nerve signal is transferred by chemicals which diffuse across the gap

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24
Q

What is the name of the passage of information in a reflex (receptor to effector)?

A

The reflex arc

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25
Q

What conditions in your body need to be controlled?

A

Ion content, sugar content, water content and temperature

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26
Q

What is ion content regulated by?

A

The kidneys

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27
Q

How is ion content regulated?

A

It is removed via the skin when we sweat and through the kidneys in the urine

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28
Q

How is water content regulated?

A

Leaves the body via the lungs when we breathe out, via the sweat and via the kidneys in the urine

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29
Q

Why is temperature controlled?

A

To maintain the temperature at which enzymes work best

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30
Q

What controls body temperature?

A

The brain

31
Q

Why are blood sugar levels controlled?

A

To provide the cells with a constant supply of energy

32
Q

What hormone controls blood sugar levels?

A

Insulin

33
Q

Where are hormones produced and secreted?

A

In the glands

34
Q

How do hormones travel?

A

In the bloodstream

35
Q

What are hormones?

A

Chemical messengers which travel in the blood to activate target cells

36
Q

Which hormones does the pituitary gland produce?

A

FSH and LH, involved in the menstrual cycle

37
Q

Which hormone does the ovary produce?

A

Oestrogen, involved in the menstrual cycle

38
Q

How do hormones act compared to nerves?

A

Slower action but for a longer time. They also act in a more general way

39
Q

What chemical substance controls many processes in the body?

A

Hormones

40
Q

What is an example of a function in the body that hormones regulate?

A

The menstrual cycle

41
Q

What does the hormone FSH do?

A

It causes eggs to mature in the ovaries. It also stimulates the ovaries to produce oestrogen

42
Q

What does the hormone LH do?

A

It stimulates the release of an egg from the ovary

43
Q

What does the hormone oestrogen do?

A

Inhibits further production of FSH

44
Q

What is the first stage of the menstrual cycle?

A

When the bleeding starts. This is due to the uterus lining breaking down for about four days

45
Q

What is the second stage of the menstrual cycle?

A

The lining of the uterus builds up again, from day 4 to 14, into a thick spongy layer full of blood vessels ready to receive a fertilised egg

46
Q

What is the third stage of the menstrual cycle?

A

An egg is released from the ovary at day 14

47
Q

What is the fourth stage of the menstrual cycle?

A

The wall is maintained for about 14 days, until day 28. if no fertilised egg has landed on the uterus wall by day 28, the spongy lining begins to break down again and the whole cycle starts again

48
Q

Which hormones can be used in the reducing of fertility?

A

Oestrogen and progesterone

49
Q

Why is oestrogen in oral contraceptives?

A

It inhibits the production of FSH

50
Q

Why is progesterone used in oral contraceptives?

A

It stimulates the production of a thick cervical mucus which prevents any sperm getting through and reaching the egg

51
Q

What did the first pill contain?

A

High levels of oestrogen

52
Q

Why was the level of oestrogen in the pill reduced?

A

Women experienced side effects

53
Q

Why are progesterone only pills being used more?

A

They have fewer side effects

54
Q

What hormone can be injected into women to stimulate egg release?

A

FSH and LH

55
Q

What does IVF involve?

A

Collecting eggs from the women’s ovaries and fertilising them in a lab with the man’s sperm. These are then grown into embryos. Once the embryos are tiny balls of cells , one or two of them are transferred into the women’s uterus to improve the chance of preganancy

56
Q

What hormones are given in IVF before egg collection?

A

FSH and LH to stimulate egg production

57
Q

What are plants sensitive to?

A

Light, Moisture and Gravity

58
Q

What do shoots grow towards?

A

Light

59
Q

What do shoots grow against?

A

The force of gravity

60
Q

What do roots grow towards?

A

Moisture

61
Q

What direction do roots grow in?

A

The force of gravity

62
Q

What hormone do plants release to control growth?

A

Auxin

63
Q

What is the name given to the growth of a plant in response to light?

A

Phototropism

64
Q

What is the name given to the growth of a plant in response to gravity?

A

Gravitropism / Geotropism

65
Q

Where is auxin produced?

A

At the tips

66
Q

What happens when there is extra auxin?

A

Growth is stimulated in the shoots but inhibited in the roots

67
Q

When a shoot is exposed to light, more auxin accumulates on…

A

The side that’s in the shade than the side in the light

68
Q

When a root is growing sideways, the auxin will build up on…

A

The lower side of the root

69
Q

Auxin in shoots causes the cells to…

A

Grow faster (elongate more) on the shaded side so the shoot bends towards the light

70
Q

The responses of plant roots and shoots is the result of…

A

The unequal distribution of hormones, causing unequal growth rate

71
Q

When a shoot is growing sideways, gravity causes more auxin to build up on…

A

The lower side of the root, causing the lower side cells to grow faster and bend the shoot upwards

72
Q

Auxin in roots causes the cells to…

A

Stop growing. This means the cells on the top grow faster and the roots bend downwards

73
Q

When a root is exposed to moisture, more auxin accumulates on…

A

The side with more moisture

74
Q

What can plant hormones be used for in agriculture and horticulture?

A

Weedkillers and rooting hormones