Unit 3.5.1 - Stimuli, both internal and external, are detected and lead to a response Flashcards

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1
Q

What is the fovea?

A

The area in the retina where there are lots of photoreceptors

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2
Q

How many rod and cone cells join to a neurone?

A

Rod - many Cone - one

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3
Q

Name two types of mechanical stimuli?

A

Pressure an vibrations

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4
Q

What is kinesis?

A

A non directional movement in response to a stimuli

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5
Q

Are the shoots/roots negatively or positively geotropic?

A

Shoots - negative Roots - positive

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6
Q

ADD STUFF ABOUT HEART RATE PATHWAYS

A

ADD STUFF ABOUT HEART RATE PATHWAYS

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7
Q

What is the sympathetic nervous system?

A

The fight and flight system that gets the body ready for action

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8
Q

Give an example of kinesis?

A

Woodlice move more often when the air gets drier so they can move to a more humid area to prevent water loss

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9
Q

Why are there many different types of receptors?

A

They are specific so only detect one stimuli, so you need many different ones to detect many different stimuli

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10
Q

What does the autonomic nervous system control?

A

Unconscious activities

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11
Q

In terms of light which side of the root or shoot does the auxin accumulate on?

A

The side away from the light

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12
Q

What is meant by simple responses are automatic?

A

The organism doesn’t choose where to move

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13
Q

What do relay neurones do?

A

Transmit electrical impulse between the sensory and motor neurone within the CNS

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14
Q

What do motor neurones do?

A

Transmit electrical impulses from the CNS to the effectors

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15
Q

Draw a pacinian corpuscle.

A
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16
Q

How does the SAN cause the heart to beat?

A

It sends out electrical impulses which cause the cardiac muscle to contract

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17
Q

What is a growth factor?

A

Chemicals that speed up of slow down the plant growth, found in growing regions of the plants

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18
Q

Do cone cells give high or low visual activity? And why?

A

High because cones are close together and one cone joins to one neurone so light from two objects close together hits two cones ad generates two action potentials so you can tell the points apart

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19
Q

What is the peripheral system made up of?

A

The neurones that connect the CNS to the rest of the body

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20
Q

How do pacinian corpuscles generate an action potential in four steps?

A

1.) When it is stimulated the lamellae are deformed and press on the sensory neurone 2.) This causes deformations of stretch-mediated sodium channels and causes them to open 3.) Sodium ions diffuse into the cell creating a generator potential 4.) If the generator potential reaches the threshold it will trigger an action potential

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21
Q

What effect does auxin have in shoots?

A

Stimulates growth

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22
Q

What two forms can receptors take?

A

Cells or proteins on cell surface membranes

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23
Q

What is another name for tactic response?

A

Taxis

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24
Q

What is a simple reflex?

A

A rapid, involuntary response to a stimuli

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25
Q

Is heart rate controlled by the sympathetic or parasympathetic nervous system? And why?

A

Both - one increases it where as the other decreases it

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26
Q

How sensitive are cone cells to light? And why?

A

Not very sensitive because one cone joins to one neurone so it takes more light to reach the threshold

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27
Q

What focuses the light rays onto the retina?

A

The lens

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28
Q

What is a stimulus?

A

A change in the internal or external environment

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29
Q

What carries the nerve impulses from the photoreceptors to the brain?

A

The optic nerve

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30
Q

What type of vision do rod cells provide?

A

Monochromatic vision

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31
Q

What is tropism?

A

A response by a plant to a directional stimulus which maintains the roots and shoots in a favourable environment

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32
Q

What is the CNS made up of?

A

The brain and the spinal cord

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33
Q

How sensitive are rod cells to light? And why?

A

Very sensitive to light because many rods join to one neurone, so many weak generator potentials combine to reach the threshold

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34
Q

What is a taxis?

A

A directional movement in response to a stimuli

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35
Q

What is meant by visual activity?

A

The ability to tell apart points that are close together

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36
Q

Where are cone cells more commonly found?

A

Packed together in the fovea

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37
Q

Where are auxins produced?

A

In the tips of shoots/roots

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38
Q

What type of receptors of pacinian corpuscles?

A

Mechanoreceptors

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39
Q

What type of stimuli do pacinian corpuscles detects?

A

Mechanical stimuli

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40
Q

What are photoreceptors?

A

Receptors in the eye that detect light

41
Q

What type of receptors detect internal stimuli that affect the rate at which the heart needs to beat?

A

Pressure receptors an chemical receptors

42
Q

What is an effector

A

A cell that brings about a response to a stimulus, to produce an effect

43
Q

What is meant by monochromatic vision?

A

Black and white vision

44
Q

Do rod cells give high or low visual activity? And why?

A

Low because many rods join to one neurone so light from two objects lose together can’t be told apart

45
Q

What causes the heart to beat?

A

The SAN

46
Q

Give an example of taxis?

A

Woodlice move away from light

47
Q

What are the five steps in a simple reflex?

A

Stimulus - Receptor - Coordinator - Effector - Response

48
Q

Name a pressure receptor and where it is located?

A

Baroreceptors - in the aorta, vena cava and the carotid arteries

49
Q

Draw a sensory neurone.

A
50
Q

Why does a plant stop growing is the tip of the shoot is removed?

A

There will be no auxin available and so the shoot stops growing

51
Q

What two systems is the nervous system split into?

A

The CNS and the peripheral system

52
Q

What is negative tropism?

A

Growth away from the stimulus

53
Q

Describe the structure of a pacinian corpuscle.

A

The end of a sensory neurone which is wrapped in loads of layers of connect tissue called lamellae

54
Q

What do auxin respond to stimuli with?

A

Growth factors

55
Q

Why do we have reflexes?

A

To protect the body from danger, as you don’t have to think about the response the response happened quickly avoiding damage

56
Q

How is an action potential triggered in photoreceptors in four steps?

A

1.) When light hits the photoreceptors it is absorbed by light sensitive pigments 2.) The light bleaches the pigment causing a chemical change and altering the membrane permeability to sodium 3.) Sodium ions diffuse into the cell creating a generator potential 4.) If the generator potential reaches the threshold it will trigger an action potential

57
Q

Where are pacinian corpuscles found?

A

In the skin

58
Q

What causes the blind spot of the eye?

A

Where the optic nerve leaves the eye because there are no photoreceptors there

59
Q

What is another name for kinetic response?

A

Kinesis

60
Q

Name a chemical receptor and where it is located?

A

Chemoreceptors - in the aorta, the carotid arteries and the medulla

61
Q

What is geotropism?

A

The growth of a plant in response to gravity

62
Q

Why do reflexes happen automatically?

A

They don’t go through conscious parts of the brain so you don’t have to think about your response

63
Q

What is meant by trichromatic vision?

A

Coloured vision

64
Q

Why do animals need to alter their heart rate?

A

To respond to internal stimuli

65
Q

What type of response do simple organisms have to stimuli?

A

Simple responses

66
Q

What is a generator potentials?

A

The change in potential difference due to a stimulus

67
Q

What nervous system is heart rate controlled by, give the sub levels?

A

Peripheral nervous system - autonomic nervous system

68
Q

What are the three types of cone cells?

A

Red sensitive, blue sensitive and green sensitive

69
Q

Do rod or cone cells have high visual activity?

A

Cone

70
Q

What is the relative charge inside and outside of a receptor during the resting potential?

A

This inside of the cell is relatively negatively charged compared to the outside

71
Q

Are rod or cone cells more sensitive to light?

A

Rod

72
Q

What two systems is the autonomic nervous system split into?

A

Sympathetic nervous system and the parasympathetic nervous system

73
Q

Which are the rod cells and which are the cone cells?

A

Left - rod cells

Right - cone cells

74
Q

What controls the amount of light that enters the eye?

A

The iris

75
Q

What is the parasympathetic nervous system?

A

The rest and digest system that calms the body down

76
Q

What type of vision do cone cells provide?

A

Trichromatic vision

77
Q

What two systems is the peripheral system split into?

A

Somatic nervous system and the autonomic nervous system

78
Q

What is a resting potential?

A

The potential when the receptor is in resting state

79
Q

What do receptors detect?

A

Stimuli

80
Q

Where is the SAN located?

A

In the wall of the right atrium

81
Q

Are the shoots/roots negatively or positively phototropic?

A

Shoots - positive Roots - negative

82
Q

What is positive tropism?

A

Growth towards the stimulus

83
Q

Name the three types of neurones?

A

Sensory, motor and relay

84
Q

Name two types of photoreceptors in the eye?

A

Rod cells and cone cells

85
Q

What two systems to receptors communicate with effectors through?

A

Nervous system and the hormonal system

86
Q

What is an action potential?

A

If a generator potential is big enough, pass the threshold level it’ll trigger an action potential

87
Q

What is a directional stimulus?

A

A stimulus coming from a particular direction

88
Q

What do sensory neurones do?

A

Transmit electrical impulses from the receptors to the CNS

89
Q

What are the two types of simple response?

A

Tactic response or kinetic response

90
Q

Where does light enter the eye through?

A

The pupil

91
Q

What does the somatic nervous system control?

A

Conscious activities

92
Q

Where are rod cells more commonly found?

A

In the peripheral parts of the retina

93
Q

What is a reflex arc?

A

The pathway of neurones linking the receptors and effectors in a simple reflex

94
Q

Draw a simple reflex arc.

A
95
Q

What part of the brain is the rate at which the SAN controlled by?

A

The medulla oblongata

96
Q

What is phototropism?

A

The growth of a plant in response to light

97
Q

In terms of gravity which side of the root or shoot does the auxin accumulate on?

A

The side nearest gravity

98
Q

Name three different potentials.

A

Resting, generator and action

99
Q

What effect does auxin have in roots?

A

Inhibits growth