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biology factual recall questions > Stimuli and response and nervous coordination > Flashcards

Stimuli and response and nervous coordination Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Why do organisms respond to changes in their environment

A

To increase survival chance

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2
Q

Define Taxis response

A

A simple response directional response in which a whole organism moves towards or away from a stimulus

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3
Q

Define Kinesis response

A

Random movement of a whole organism in response to a non directional stimuli eg temperature or humidity. this may be an increase/decrease in speed or turning frequency

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4
Q

How do plants respond to stimuli

A

Using growth factors

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5
Q

What is IAA

A

Auxin. It is a plant hormone. It allows plants to be photo and gravotrophic

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6
Q

Where in a plant is IAA produced

A

The tips of roots and shoots

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7
Q

How does IAA effect cells in shoots and roots

A

It promotes cell elongation in shoots and restricts it in roots

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8
Q

Outline the pathway of a simple reflex arc

A

Stimulus - receptors - sensory neurone - CNS- relay neurone - motor neurone - Effectors- response

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9
Q

What three neurones are involved in a simple reflex arc

A

Sensory neurone, replay neurone, motor neurone

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10
Q

What purpose does a simple reflex arc serve

A

Protective response to increase survival chance

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11
Q

What do the Pacinian corpuscles detect

A

Mechanical pressure

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12
Q

What ion channels are present in the Pacinian corpuscles

A

Stretch mediated sodium ion channels

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13
Q

What is established when a receptor is stimulated

A

A generator potential

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14
Q

When is an action potential triggered

A

When a generator potential exceeds a threshold

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15
Q

What is the connective tissue called that is wrapped around the sensory nerve ending in Pacinian corpuscles

A

Lamellae

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16
Q

What two types of cells detect light in the eyes

A

Rod cells

cone cells

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17
Q

Which type of cell has high visual acuity

A

cone cells

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18
Q

Why do the two types of cells have different visual acuity

A

Several rod cells connect to one bipolar neurone. This means that they are sensitive but have low visual acuity as it isn’t possible to tell which exact rod cell(s) was stimulated

A cone cell is attached to a single bipolar neurone. This means that they have high visual acuity

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19
Q

Which of the two types of cell is most sensitive to light

A

Rod cells

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20
Q

Which type of cell is responsible for trichromatic vision

A

cone cells

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21
Q

What is responsible for the blind spot of an eye

A

The location where the optic nerve leaves the eye is the blind spot

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22
Q

What neurone connects photoreceptors to the optic nerve

A

bipolar neurone

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23
Q

What is different about myogenic muscle tissue

A

It can contract and relax without receiving signals from nerves
Cardiac muscle fibres are Myogenic

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24
Q

Outline the roles of the sinoatrial node (SAN)

A

Sends regular electrical impulses to the atrial walls to control heart rate. Causes right and left atria to contract simultaneously

Often referred to as pacemaker

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25
Q

Outline the roles of the Atrioventricular node (AVN)

A

Passes the impulse to the bundles of His. Has a slight delay to ensure atria are empty

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26
Q

Outline the roles of the Bundle of His

A

Through the atrioventricular septum to the base of the ventricles where the bundle branches into smaller fibres of purkyne tissue. The wave of excitation is released from the purkyne tissue causing the ventricles to contract quickly at the same time from the bottom of the heart upwards

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27
Q

Outline the roles of the Purkyne tissue

A

This tissue is fibres from the bundle of His. It carries waves of electrical activity into the ventricle walls, causing simultaneous contraction from the bottom up

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28
Q

What section of the brain subconsciously controls the rate at which the SAN fires

A

Medulla

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29
Q

Where are the baroreceptors located and what are they stimulated by

A

Aorta and carotid arteries - pressure

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30
Q

Where are the chemoreceptors located and what are they stimulated by

A

Aorta, carotid arteries and medulla. O2 levels, CO2 levels and Ph (which indicates O2 levels)

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31
Q

What effectors are related to slow down heart rate

A

Acetylcholine, which binds to receptors on the SAN

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32
Q

What effectors are related to speed up heart rate

A

Noradrenaline, which binds to receptors on the SAN

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33
Q

When low 02, high CO2 or low blood pH is detected, how is heart rate changed to bring back normal levels

A

Heart rate is increased. This is done by releasing noradrenaline

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34
Q

State the equation linking Cardiac Output (CO), Stroke Volume (V) and Heart Rate (R)

A

CO=VxR

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35
Q

What is a myelin sheath

A

An electrical insulator

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36
Q

What ells are myelin sheaths made from

A

Schwann cells

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37
Q

What is the term for the bare patches of membrane between the cells

A

Nodes of Ranvier

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38
Q

What are sodium ion changes concentrated at

A

Nodes of Ranvier

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39
Q

In a myelinated neurone, where does depolarisation occur

A

Nodes of Ranvier

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40
Q

How does myelination effect the speed of conduction

A

Increases it all less depolarisation has to occur

41
Q

Give two other features that would effect speed of conduction

A

Temperature

Axon Diameter

42
Q

When a resting potential is established how is the outside of a cell charged in comparison with the inside

A

It is positively charged

43
Q

What proteins create and maintain a resting potential

A

Potassium ion channels, Sodium potassium pumps

44
Q

Why are there more sodium ions outside the cell than on the inside

A

They are actively transported out and the cell membrane is not very permeable to them

45
Q

When a stimulus is detected, what channel proteins open

A

Na+ channels open

46
Q

What occurs when the threshold is reached

A

Lots more Na+ channels open

47
Q

When repolarisation occurs, how does the membrane permeability to sodium and potassium change

A

Impermeable to sodium, permeable to potassium

48
Q

What effect does the refractory period have on nervous impulses

A

Acts as a time delay so impulses don’t overlap. Ensures impulses are discrete. Means there is a limit to how often impulses can fire

49
Q

As described thy the all-or-nothing principle, how would a bigger stimulus effect the size of an action potential

A

No change

50
Q

As described thy the all-or-nothing principle, how would a bigger stimulus effect the frequency at which an action potential fires

A

Faster frequency

51
Q

What is contained in the vesicles of the presynaptic knob

A

Neurotransmitters

52
Q

What is the gap between the cells at the synapse called

A

Synaptic cleft

53
Q

Why are synapses unidirectional

A

Only the post-synaptic neurone has receptors

54
Q

When an action potential arrives at a Cholinergic synapse, what three steps happen

A

Ca2+ ions move into presynaptic knob. Vesicles with Each fuse with membrane of synapse releasing neurotransmitter. This diffuses across the synaptic cleft and activates the receptors. The neurotransmitter is then broken down by AChE

55
Q

What is summation in relation to synapses

A

Where the effect of many neurones, or one stimulated multiple times, is added together

56
Q

State the names of both types of summation

A

Spatial summation

temporal summation

57
Q

How is ACh removed from he synaptic junction

A

AChE breaks it down and the products are reabsorbed by the presynaptic neuyrone

58
Q

What are stored in clefts at a neuromuscular junction

A

AChE

59
Q

suggest 2 advantages of simple reflexes

A 
rapid
protect against damage to the body
do not have to be learnt
help escape predators
enable homeostatic control
60
Q

stimuli are detected by

A

receptors

61
Q

a response to a stimuli is controlled by a

A

coordinator (brain)

62
Q

a response to a stimuli (eg hormone secretion) is produced by

A

an effector

63
Q

Movement of a whole organism towards light is called, and give an example of such an organism

A

phototaxis (algae)

64
Q

Positive taxis is

A

movement towards a stimulus by a whole organism

65
Q

Negative taxis is

A

movement away from a stimulus by a whole organism

66
Q

define tropism

A

the growth of part of a plant in response to a directional stimulus eg light, gravity or water

67
Q

when plants grow towards light it is called

A

positive phototropism

68
Q

when plant shoots grow away from gravity it is called

A

negative gravitropism

69
Q

When plant roots grow away from light it is called

A

negative phototropism

70
Q

Why do woodlice increase their rate of turning if they exit favourable conditions

A

to increase the probability that they will reenter the favourable conditions

71
Q

why do woodlice decrease their rate of turning and move rapidly after spending a while in unfavourable conditions

A

to increase the chances that they will pas through the unfavourable conditions and enter more favourable ones

72
Q

When roots grow towards water it is called

A

positive hydrotropism

73
Q

give the location of the osmoreceptors in the body of a mammal

A

hypothalamus

74
Q

the pressure receptors in the skin are called

A

pacinian corpuscles

75
Q

what is a transducer

A

a receptor cell which converts one form of energy (eg light) into a form that can be understood by the body (eg an electrical impulse)

76
Q

What is a stretch mediated sodium channel

A

a sodium channel protein whose permeability to sodium ions increases they they are deformed

77
Q

In which part of the eye are light receptor cells found

A

the retina

78
Q

rod cells are responsible for _____ vision

A

black and white

79
Q

why can rod cell images only be seen in black and white

A

they can not distinguish between different wavelengths of light

80
Q

rod cells are sensitive to ____ intensity light

A

low

81
Q

cone cells are sensitive to _____ intensity light

A

high

82
Q

which pigment, that breaks down in low intensity light, is found inside rod cells

A

rhodopsin

83
Q

How many types of cone cell are there

A

3

84
Q

each of the 3 types of cone cell contain a specific group of pigments called

A

iodopsins

85
Q

does iodopsin break down in the presence of high or low intensity light

A

high

86
Q

where does the lens of the eye focus light

A

fovea

87
Q

where is the fovea

A

central point in the retina

88
Q

outer periphery of the retina contains ____ cells

A

rod

89
Q

the fovea contains ____

A

cone

90
Q

what are cholinergic synapses

A

synapses that use acetylcholine

91
Q

What is a synapse

A

the junction between a neurone and the next cell

92
Q

what ensures that impulses cross the synapse in one direction only

A

Neurotransmitter is released from the presynaptic knob. Receptor for the neurotransmitter is only found on the post synaptic membrane

93
Q

what happens to the neurotransmitter once they have attached to the receptors on the post synaptic membrane

A

They are broken down by enzymes and their products are taken back into the neurone

94
Q

What stimulates the synaptic vesicles to move towards the presynaptic membrane in a cholinergic synapse

A

Calcium ions diffuse into the synaptic knob causing the synaptic vesicles to move towards the presynaptic membrane

95
Q

What happens when the acetylcholine bind with the receptors on the post synaptic membrane

A

Sodium channels open and sodium floods in. If the threshold is reached an action potential is generated

96
Q

How is acetylcholine removed from the synaptic cleft

A

Acetylcholinesterase breaks acetylcholine and the products are reabsorbed to make more acetylcholine

97
Q

What is temporal summation

A

where there are two or more nerve impulses that arrive in quick succession from the same presynaptic membrane and action potential is more likely to occur

98
Q

What is spatial summation

A

When many neurones connect to one neurone. The small amount of neurotransmitter released from each of these neurones can be enough to reach the threshold value

99
Q

What are the nodes of Ranvier

A

Bare areas of neurones that are not insulated by myelin

biology factual recall questions (9 decks)

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