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Biology Edexcel Sophie > Topic 7 Muscles > Flashcards

Topic 7 Muscles Flashcards

1
Q

What are the components involved in movement?

A

Skeletal muscles, tendons, ligaments, and joints

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2
Q

How are skeletal muscles attached to bones?

A

By tendons

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3
Q

What type of muscle is used for movement?

A

Skeletal muscle

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4
Q

What is the role of ligaments?

A

Attach bones to other bones

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5
Q

What happens when skeletal muscles contract?

A

They move bones at a joint

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6
Q

What are the two muscles involved in moving the lower arm?

A

Biceps and triceps

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7
Q

What is the term for a muscle that bends a joint when it contracts?

A

Flexor

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8
Q

What is the term for a muscle that straightens a joint when it contracts?

A

Extensor

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9
Q

What are muscles that work together to move a bone called?

A

Antagonistic pairs

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10
Q

Why do muscles work in pairs?

A

Because they can only pull and not push

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11
Q

What are skeletal muscle fibers made up of?

A

Large bundles of long cells called muscle fibers

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12
Q

What is the cell membrane of muscle fiber cells called?

A

Sarcolemma

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13
Q

What are transverse (T) tubules?

A

Folds of the sarcolemma that spread electrical impulses

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14
Q

What does the sarcoplasmic reticulum do?

A

Stores and releases calcium ions needed for muscle contraction

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15
Q

What is the function of mitochondria in muscle fibers?

A

Provide ATP needed for muscle contraction

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16
Q

What does it mean that muscle fibers are multinucleate?

A

They contain many nuclei

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17
Q

What are myofibrils?

A

Long, cylindrical organelles made up of proteins highly specialized for contraction

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18
Q

What is the structural unit of a myofibril?

A

Sarcomere

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19
Q

What are the dark bands in myofibrils called?

A

A bands

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20
Q

What are the light bands in myofibrils called?

A

I bands

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21
Q

What is the M-line?

A

The middle of the sarcomere

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22
Q

What is the H-zone?

A

The region around the M-line that only contains thick filaments

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23
Q

What are the two main proteins involved in muscle contraction?

A

Myosin and actin

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24
Q

True or False: Sarcomeres contract simultaneously to shorten the muscle.

A

True

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25
Q

Fill in the blank: Skeletal muscle fibers have lots of _______ to provide ATP.

A

Mitochondria

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26
Q

What are the components involved in movement?

A

Skeletal muscles, tendons, ligaments, and joints

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27
Q

How are skeletal muscles attached to bones?

A

By tendons

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28
Q

What type of muscle is used for movement?

A

Skeletal muscle

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29
Q

What is the role of ligaments?

A

Attach bones to other bones

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30
Q

What happens when skeletal muscles contract?

A

They move bones at a joint

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31
Q

What are the two muscles involved in moving the lower arm?

A

Biceps and triceps

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32
Q

What is the term for a muscle that bends a joint when it contracts?

A

Flexor

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33
Q

What is the term for a muscle that straightens a joint when it contracts?

A

Extensor

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34
Q

What are muscles that work together to move a bone called?

A

Antagonistic pairs

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35
Q

Why do muscles work in pairs?

A

Because they can only pull and not push

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36
Q

What are skeletal muscle fibers made up of?

A

Large bundles of long cells called muscle fibers

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37
Q

What is the cell membrane of muscle fiber cells called?

A

Sarcolemma

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38
Q

What are transverse (T) tubules?

A

Folds of the sarcolemma that spread electrical impulses

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39
Q

What does the sarcoplasmic reticulum do?

A

Stores and releases calcium ions needed for muscle contraction

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40
Q

What is the function of mitochondria in muscle fibers?

A

Provide ATP needed for muscle contraction

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41
Q

What does it mean that muscle fibers are multinucleate?

A

They contain many nuclei

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42
Q

What are myofibrils?

A

Long, cylindrical organelles made up of proteins highly specialized for contraction

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43
Q

What is the structural unit of a myofibril?

A

Sarcomere

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44
Q

What are the dark bands in myofibrils called?

A

A bands

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45
Q

What are the light bands in myofibrils called?

A

I bands

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46
Q

What is the M-line?

A

The middle of the sarcomere

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47
Q

What is the H-zone?

A

The region around the M-line that only contains thick filaments

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48
Q

What are the two main proteins involved in muscle contraction?

A

Myosin and actin

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49
Q

True or False: Sarcomeres contract simultaneously to shorten the muscle.

A

True

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50
Q

Fill in the blank: Skeletal muscle fibers have lots of _______ to provide ATP.

A

Mitochondria

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51
Q

What are the two main types of filaments in muscle contraction?

A

Thick myofilaments (myosin) and thin myofilaments (actin)

Myosin and actin are the proteins that make up the muscle fibers and are essential for muscle contraction.

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52
Q

What are A-bands and I-bands in muscle fibers?

A

A-bands contain thick myosin filaments and overlapping thin actin filaments; I-bands contain only thin actin filaments

A-bands appear dark, while I-bands appear light under a microscope.

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53
Q

What marks the ends of each sarcomere?

A

Z-line

The Z-line is crucial for the structural integrity of the sarcomere.

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54
Q

What is the M-line in a sarcomere?

A

The middle of the myosin filaments

The M-line serves as an anchoring point for myosin filaments.

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55
Q

What does the H-zone contain?

A

Only myosin filaments

The H-zone is the area in a sarcomere where there are no overlapping actin filaments.

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56
Q

What theory explains muscle contraction?

A

Sliding Filament Theory

This theory states that myosin and actin filaments slide over each other to contract the sarcomeres.

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57
Q

What happens to the length of sarcomeres during contraction?

A

Sarcomeres get shorter

The A-bands remain the same length, while the I-band and H-zone get shorter.

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58
Q

Fill in the blank: The __________ are the functional units of muscle fibers.

A

sarcomeres

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59
Q

What is the relationship between myofilaments, muscle fibers, myofibrils, and muscles?

A

Myofilaments form myofibrils, which make up muscle fibers, which together form muscles

This hierarchical structure is essential for muscle function.

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60
Q

True or False: When a muscle contracts, the myofilaments themselves change length.

A

False

The myofilaments do not change length; rather, they slide past each other.

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61
Q

What are antagonistic pairs in muscle movement?

A

Muscles that work together to move a bone by one contracting while the other relaxes

This mechanism allows for controlled movement, such as bending and straightening limbs.

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62
Q

What is the role of transverse (T) tubules in muscle fibers?

A

They help transmit electrical signals deep into the muscle fiber

This process is crucial for initiating muscle contraction.

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63
Q

What do myosin filaments have that allows them to move back and forth?

A

Globular heads and binding sites

Myosin filaments have globular heads that are hinged.

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64
Q

What proteins are found between actin filaments that help myofilaments move past each other?

A

Tropomyosin and troponin

These proteins are essential for the muscle contraction process.

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65
Q

What blocks the actin-myosin binding site in resting muscles?

A

Tropomyosin

Tropomyosin is held in place by troponin.

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66
Q

What triggers muscle contraction?

A

An action potential

The action potential comes from a motor neurone.

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67
Q

What happens to the sarcolemma during depolarisation?

A

The difference in charge across the sarcolemma is reduced

This is a crucial step in triggering muscle contraction.

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68
Q

What is released from the sarcoplasmic reticulum when it is stimulated?

A

Calcium ions (Ca²⁺)

These ions play a key role in muscle contraction.

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69
Q

What does calcium bind to, causing a change in shape?

A

Troponin

This binding pulls tropomyosin out of the actin-myosin binding site.

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70
Q

What is formed when a myosin head binds to an actin filament?

A

An actin-myosin cross bridge

This bond is essential for muscle contraction.

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71
Q

What enzyme is activated by calcium ions to provide energy for muscle contraction?

A

ATPase

ATPase breaks down ATP into ADP + Pᵢ.

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72
Q

What happens to the actin filament when the myosin head moves?

A

It is pulled along in a rowing action

This movement leads to muscle contraction.

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73
Q

What provides the energy needed to detach the myosin head from the actin filament?

A

ATP

ATP is crucial for both movement and detachment processes.

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74
Q

What occurs after the myosin head detaches from the actin filament?

A

It reattaches to a different binding site

This process repeats, forming many cross bridges quickly.

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75
Q

What happens to the sarcomere during muscle contraction?

A

It shortens

This shortening results from the sliding of actin filaments.

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76
Q

What is required for the cycle of muscle contraction to continue?

A

Calcium ions must be present and bound to troponin

This ensures that the binding sites remain exposed.

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77
Q

Fill in the blank: In skeletal muscles, the muscle fibers that are good for endurance are known as _______.

A

Slow twitch

Slow twitch fibers are characterized by high mitochondrial content and reddish color.

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78
Q

What type of muscles are good for posture and long-distance activities?

A

Skeletal muscles

These muscles can work for a long duration due to their energy efficiency.

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79
Q

What happens to calcium ions when muscle excitation stops?

A

Calcium ions leave their binding sites in the sarcoplasmic reticulum and are transported back into the sarcoplasmic reticulum, which requires ATP.

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80
Q

What is the role of troponin in muscle contraction?

A

Troponin changes shape when calcium ions bind to it, allowing myosin heads to attach to actin filaments.

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81
Q

What is the effect of tropomyosin when muscle contraction stops?

A

Tropomyosin blocks the actin-myosin binding sites, preventing myosin heads from attaching to actin filaments.

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82
Q

What occurs to the actin filaments when muscle relaxation happens?

A

The actin filaments slide back to their relaxed position, lengthening the sarcomere.

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83
Q

What are the two types of skeletal muscle fibres?

A

Slow twitch and fast twitch muscle fibres.

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84
Q

List three properties of slow twitch muscle fibres.

A
  • Contract slowly
  • Good for endurance activities
  • Rich in mitochondria and myoglobin
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85
Q

List three properties of fast twitch muscle fibres.

A
  • Contract very quickly
  • Good for short bursts of speed and power
  • Rich in glycogen
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86
Q

What is the primary energy source for slow twitch muscle fibres?

A

Aerobic respiration.

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87
Q

What is the primary energy source for fast twitch muscle fibres?

A

Anaerobic respiration using glycogen.

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88
Q

What color are slow twitch muscle fibres and why?

A

Reddish in color due to high myoglobin content.

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89
Q

What color are fast twitch muscle fibres and why?

A

Whitish in color due to low myoglobin content.

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90
Q

Which molecule blocks the actin-myosin binding site in resting muscles?

A

Tropomyosin.

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91
Q

What is the name of the bond formed when a myosin head binds to an actin filament?

A

Actin-myosin cross bridge.

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92
Q

Fill in the blank: Rigor mortis is the stiffening of muscles in the body after death. It happens when _______ reserves are exhausted.

A

ATP

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93
Q

Describe the effect of Bepridil on muscle contraction.

A

Bepridil blocks calcium ion channels, preventing calcium ions from entering the muscle cells, which inhibits muscle contraction.

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94
Q

What is the overall equation for aerobic respiration?

A

C6H12O6 (glucose) + 6O2 = 6CO2 + 6H2O + Energy

This equation summarizes the process of aerobic respiration, highlighting the reactants and products involved.

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95
Q

What is the primary purpose of the energy released during aerobic respiration?

A

To phosphorylate ADP to ATP

ATP is then used to provide energy for all biological processes inside a cell.

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96
Q

What are the four stages of aerobic respiration?

A
  • Glycolysis
  • Link reaction
  • Krebs cycle
  • Oxidative phosphorylation

The first three stages involve a series of reactions that produce products used in the final stage to produce ATP.

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97
Q

Where does glycolysis occur in the cell?

A

In the cytoplasm

The other three stages of aerobic respiration take place in the mitochondria.

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98
Q

What is a rate-limiting enzyme?

A

The enzyme with the slowest activity that determines the overall rate of respiration

Each reaction in respiration is controlled and catalyzed by specific intracellular enzymes.

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99
Q

What role do coenzymes play in respiration?

A

They transfer hydrogen from one molecule to another

Examples include NAD and FAD, which can reduce or oxidize a molecule.

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100
Q

What is a respiratory substrate?

A

A molecule that can be respired, such as glucose

All cells use glucose to respire, but other complex organic molecules can also be broken down.

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101
Q

What happens during glycolysis?

A

Glucose is split into two molecules of pyruvate

This process occurs in the cytoplasm and does not require oxygen.

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102
Q

What are the two stages of glycolysis?

A
  • Phosphorylation
  • Oxidation

During phosphorylation, ATP is used to phosphorylate glucose; in oxidation, triose phosphate is oxidized to form pyruvate.

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103
Q

What is the net gain of ATP from glycolysis?

A

2 ATP

Four ATP are produced, but 2 are used up in the phosphorylation stage.

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104
Q

What type of process is glycolysis?

A

Anaerobic process

Glycolysis does not require oxygen.

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105
Q

What happens to the two pyruvate molecules after glycolysis?

A

They go into the matrix of the mitochondria for the link reaction

This is the next step in aerobic respiration.

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106
Q

How many molecules of reduced NAD are formed during glycolysis?

A

2 molecules

These are used in the last stage of respiration (oxidative phosphorylation).

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107
Q

Fill in the blank: Glycolysis involves the partial oxidation of glucose via _______.

A

triose phosphate

To completely oxidize glucose, oxygen and the other steps in aerobic respiration are needed.

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108
Q

What is the first stage of aerobic respiration?

A

Glycolysis

Glycolysis occurs in the cytoplasm and breaks down glucose into pyruvate.

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109
Q

What is produced during the link reaction?

A

Acetyl coenzyme A (acetyl CoA)

The link reaction decarboxylates pyruvate, releasing CO2 and forming acetyl CoA.

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110
Q

How many times does the link reaction occur for each glucose molecule?

A

Twice

This is because two pyruvate molecules are produced from one glucose molecule.

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111
Q

What does NAD do during the link reaction?

A

NAD is reduced

NAD collects hydrogen from pyruvate, forming reduced NAD.

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112
Q

What is released as a waste product during the link reaction?

A

CO2

One carbon atom is removed from pyruvate, forming CO2.

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113
Q

What is the overall net gain of ATP from glycolysis?

A

2

Glycolysis uses 2 ATP but produces 4 ATP, leading to a net gain of 2 ATP.

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114
Q

Where in the cell does glycolysis occur?

A

Cytoplasm

Glycolysis takes place in the cytoplasm of the cell.

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115
Q

Is glycolysis an anaerobic or aerobic process?

A

Anaerobic

Glycolysis does not require oxygen.

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116
Q

What is the product of the link reaction?

A

Acetyl coenzyme A (acetyl CoA)

Acetyl CoA is formed from acetate and coenzyme A.

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117
Q

Name one coenzyme involved in respiration.

A

Coenzyme A (CoA)

CoA plays a crucial role in the link reaction and Krebs cycle.

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118
Q

How many ATP molecules are used up in glycolysis?

A

2

Glycolysis requires an investment of 2 ATP for the process to begin.

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119
Q

True or False: ATP is phosphorylated to form ADP during glycolysis.

A

False

ATP is generated from ADP during glycolysis, not the other way around.

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120
Q

What happens to pyruvate once produced by glycolysis?

A

It enters the link reaction

Pyruvate is converted to acetyl CoA in the link reaction.

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121
Q

What is the net gain of glycolysis?

A

2 ATP

Glycolysis is the first stage of aerobic respiration and produces a net gain of 2 ATP molecules.

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122
Q

What are the main stages of aerobic respiration?

A
  1. Glycolysis
  2. Link Reaction
  3. Krebs Cycle
  4. Oxidative Phosphorylation

These stages are essential for the complete breakdown of glucose to produce ATP.

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123
Q

How many times does the Krebs Cycle occur for each glucose molecule?

A

Twice

The Krebs Cycle occurs once for each pyruvate molecule, and since one glucose produces two pyruvate, the cycle runs twice.

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124
Q

What compound does Acetyl CoA combine with in the Krebs Cycle?

A

Oxaloacetate

Acetyl CoA combines with oxaloacetate to form citrate, initiating the Krebs Cycle.

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125
Q

What is produced during the decarboxylation process in the Krebs Cycle?

A

CO₂

Decarboxylation involves the removal of carbon dioxide from organic compounds.

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126
Q

What are the products of one turn of the Krebs Cycle?

A
  • 1 Coenzyme A
  • 2 CO₂
  • 1 ATP
  • 3 reduced NAD
  • 1 reduced FAD

These products are generated from one molecule of Acetyl CoA in the Krebs Cycle.

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127
Q

What is substrate-level phosphorylation?

A

Direct transfer of a phosphate group from one molecule to another

This process is how ATP is produced during certain steps in the Krebs Cycle.

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128
Q

What are the two processes involved in oxidative phosphorylation?

A
  • Electron transport chain
  • Chemiosmosis

These processes work together to produce ATP using the energy from reduced coenzymes.

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129
Q

How is ATP generated during chemiosmosis?

A

By the movement of protons across the mitochondrial membrane

The flow of protons through ATP synthase generates ATP.

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130
Q

What is the final electron acceptor in the electron transport chain?

A

Oxygen

Oxygen is critical for the process as it combines with electrons and protons to form water.

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131
Q

True or False: Reduced NAD and FAD are produced in the Krebs Cycle.

A

True

Both reduced NAD and reduced FAD are generated as byproducts of the Krebs Cycle.

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132
Q

Fill in the blank: Oxidative phosphorylation produces lots of _______.

A

ATP

The main purpose of oxidative phosphorylation is to generate a large amount of ATP.

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133
Q

What is the total maximum ATP yield from aerobic respiration?

A

38 ATP

This total includes ATP produced from glycolysis, Krebs Cycle, and oxidative phosphorylation.

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134
Q

What is the main function of the Krebs cycle?

A

The Krebs cycle generates reduced coenzymes NADH and FADH2 for oxidative phosphorylation.

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135
Q

Where does the Krebs cycle take place?

A

In the mitochondrial matrix.

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136
Q

What is chemiosmosis?

A

The movement of H+ ions across a membrane that generates ATP.

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137
Q

What are the final products of the electron transport chain?

A

Water (H2O) is formed from protons, electrons, and oxygen.

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138
Q

What is the role of oxygen in cellular respiration?

A

Oxygen is the final electron acceptor in the electron transport chain.

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139
Q

How many ATP are produced from one reduced NAD?

A

3 ATP.

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140
Q

How many ATP are produced from one reduced FAD?

A

2 ATP.

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141
Q

Complete the sentence: The electrochemical gradient created during oxidative phosphorylation is due to the _______ of protons.

A

concentration difference.

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142
Q

What metabolic process is inhibited by some poisons targeting electron carriers?

A

Oxidative phosphorylation.

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143
Q

What happens to reduced NAD and reduced FAD when electron transport chain activity is halted?

A

They are not oxidized, preventing regeneration for the Krebs cycle.

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144
Q

True or False: The Krebs cycle occurs only once for each molecule of glucose.

A

False.

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145
Q

How many ATP are produced during glycolysis?

A

2 ATP.

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146
Q

How many carbon dioxide molecules are produced during one turn of the Krebs cycle?

A

2 carbon dioxide molecules.

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147
Q

What is the total ATP yield from one molecule of glucose in aerobic respiration?

A

38 ATP.

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148
Q

List the stages of respiration where ATP is produced.

A
  • Glycolysis
  • Link Reaction
  • Krebs cycle
  • Oxidative phosphorylation
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149
Q

What is the consequence of insufficient ATP synthesis for cellular processes?

A

Failure to fuel ATP-requiring processes, which can be fatal.

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150
Q

What role does ATP synthase play in ATP production?

A

It synthesizes ATP from ADP and inorganic phosphate using the energy from H+ ion movement.

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151
Q

Complete the sentence: The concentration of protons is higher in the _______ than in the mitochondrial matrix.

A

intermembrane space.

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152
Q

What does a respirometer measure?

A

The volume of oxygen being taken up in a given time

The more oxygen taken up, the faster the rate of respiration.

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153
Q

How can the rate of respiration be determined?

A

By measuring the volume of oxygen taken up or the volume of carbon dioxide produced in a given time

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154
Q

What is the purpose of potassium hydroxide solution in a respirometer?

A

To absorb carbon dioxide produced during respiration

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155
Q

What is the role of the control tube in a respirometer experiment?

A

To ensure results are only due to the woodlice respiring, using beads with the same mass instead of woodlice

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156
Q

What should be done before starting a respirometer experiment?

A

Set the fluid in the manometer to a known level using a syringe

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157
Q

What happens to the volume of air in the test tube during respiration?

A

There will be a decrease in the volume of air due to oxygen consumption by the woodlice

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158
Q

What causes the colored liquid in the manometer to move towards the test tube?

A

The decrease in volume of air that reduces the pressure in the tube

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159
Q

What must be controlled to ensure accurate respirometer results?

A

Temperature and volume of potassium hydroxide solution in each test tube

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160
Q

How is the volume of oxygen taken in by the woodlice calculated?

A

By measuring the distance moved by the liquid in the manometer over a given time

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161
Q

What is lactate fermentation?

A

A process that occurs during anaerobic respiration, producing lactic acid

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162
Q

Fill in the blank: The apparatus is left for a set period of time (e.g. _______ minutes).

A

[20]

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163
Q

True or False: Other small invertebrates, such as aphids, can be used in respirometer experiments.

A

True

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164
Q

What should be ensured when working with living organisms in experiments?

A

They are treated with respect and not harmed or distressed unnecessarily

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165
Q

What is the purpose of repeating the experiment in respirometry?

A

To produce more precise results and calculate a mean volume of oxygen

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166
Q

What does a respirometer measure?

A

The rate of respiration

A respirometer is an instrument used to measure the amount of oxygen consumed or carbon dioxide produced by an organism.

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167
Q

Lactate fermentation is an example of what type of respiration?

A

Anaerobic respiration

Anaerobic respiration occurs in the absence of oxygen and includes processes like lactate fermentation.

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168
Q

Give one way that animals can break down lactate.

A

Cells can convert the lactic acid back to pyruvate

Pyruvate can then re-enter aerobic respiration at the Krebs cycle.

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169
Q

What is the first step of lactate fermentation?

A

Glycolysis

Glycolysis converts glucose to pyruvate, producing reduced NAD which is essential for lactate formation.

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170
Q

What does reduced NAD do in lactate fermentation?

A

Transfers hydrogen to pyruvate to form lactate

This process regenerates NAD, allowing glycolysis to continue under anaerobic conditions.

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171
Q

Fill in the blank: Anaerobic respiration doesn’t use _______.

A

oxygen

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172
Q

What happens to lactic acid after a period of anaerobic respiration?

A

It builds up in the body

Lactic acid accumulation can lead to muscle fatigue and discomfort.

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173
Q

How can liver cells break down lactic acid?

A

Convert the lactic acid back to glucose

This glucose can then be respired or stored in the liver.

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174
Q

What is the role of potassium hydroxide in a respirometer?

A

Absorbs carbon dioxide

This allows for the measurement of oxygen consumption without interference from CO2 production.

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175
Q

True or False: Anaerobic respiration can produce a small amount of ATP.

A

True

Even in low oxygen conditions, anaerobic respiration allows for some ATP production, which is crucial for survival.

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176
Q

What is the end product of lactate fermentation in animals?

A

Lactate (lactic acid)

This product is formed when pyruvate is reduced by NADH during anaerobic conditions.

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177
Q

What is the function of the control tube in a respirometer experiment?

A

To serve as a baseline measurement

The control tube helps account for any changes not related to respiration, ensuring accurate results.

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178
Q

Which process allows glycolysis to continue in anaerobic conditions?

A

Lactate fermentation

This process regenerates NAD from reduced NAD, facilitating ongoing ATP production.

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179
Q

Fill in the blank: The Krebs cycle occurs during _______ respiration.

A

aerobic

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180
Q

What inhibits the electron transport chain in aerobic respiration?

A

Antimycin C

This substance prevents electron transfer, affecting ATP production but not lactate formation.

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181
Q

What is produced from the breakdown of glucose during glycolysis?

A

Pyruvate

Pyruvate is a key intermediate that can enter either aerobic respiration or anaerobic fermentation.

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182
Q

What is the role of the sino-atrial node (SAN) in the heart?

A

The SAN sets the rhythm of the heartbeat by sending out regular waves of electrical activity to the atrial walls.

The SAN is often referred to as the heart’s pacemaker.

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183
Q

What happens when the SAN sends out electrical activity?

A

It causes the right and left atria to contract at the same time.

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184
Q

What type of tissue prevents electrical activity from passing directly from the atria to the ventricles?

A

A band of non-conducting collagen tissue.

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185
Q

What is the function of the atrioventricular node (AVN)?

A

The AVN passes the waves of electrical activity on to the bundle of His after a slight delay.

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186
Q

What is the bundle of His responsible for?

A

Conducting the waves of electrical activity to the Purkyne fibres in the ventricles.

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187
Q

What are Purkyne fibres?

A

Finer muscle fibres in the right and left ventricle walls that carry the waves of electrical activity.

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188
Q

How do the ventricles contract?

A

They contract simultaneously from the bottom up.

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189
Q

What is an electrocardiograph?

A

A machine that records the electrical activity of the heart.

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190
Q

What does the heart muscle do when it contracts and relaxes?

A

It depolarises (loses electrical charge) when it contracts and repolarises (regains charge) when it relaxes.

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191
Q

What is the trace produced by an electrocardiograph called?

A

Electrocardiogram (ECG).

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192
Q

What does the P wave in an ECG represent?

A

Contraction (depolarisation) of the atria.

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193
Q

What is the QRS complex in an ECG?

A

The main peak of the heartbeat, caused by contraction (depolarisation) of the ventricles.

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194
Q

What does the T wave in an ECG indicate?

A

Relaxation (repolarisation) of the ventricles.

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195
Q

Fill in the blank: A bigger wave in the P and R waves of an ECG indicates a _______.

A

stronger contraction.

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196
Q

True or False: Doctors use ECGs to compare the heart’s rhythm with healthy conditions.

A

True.

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197
Q

What might an ectopic heartbeat indicate?

A

It suggests that there is an additional contraction that occurs earlier than expected.

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198
Q

Describe the purpose of an electrocardiograph in cardiac health assessment.

A

To record the electrical activity of the heart and assess heart function.

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199
Q

What is tachycardia?

A

A heartbeat that is too fast, around 120 beats per minute.

It may be normal during exercise but indicates inefficient blood pumping at rest.

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200
Q

What is bradycardia?

A

A heartbeat that is too slow, below 60 beats per minute at rest.

This condition can indicate potential heart issues.

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201
Q

What is an ectopic heartbeat?

A

An ‘extra’ heartbeat caused by earlier contraction of the atria or ventricles.

Occasional ectopic heartbeats in healthy individuals typically do not cause problems.

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202
Q

What does fibrillation indicate?

A

A really irregular heartbeat where the atria or ventricles lose rhythm and stop contracting properly.

It can lead to symptoms ranging from chest pain to fainting and even death.

203
Q

What prevents impulses from the atria travelling straight into the ventricles?

A

The atrioventricular node (AVN).

204
Q

What structure picks up impulses from the atria and passes them on to the ventricles?

A

The bundle of His.

205
Q

What is the function of the Purkyne fibres?

A

To conduct electrical impulses to the ventricles, causing them to contract.

206
Q

What causes the P wave of an ECG trace?

A

The depolarization of the atria.

207
Q

True or False: Occasional ectopic heartbeats are always a cause for concern.

A

False.

208
Q

Fill in the blank: A heartbeat that is too fast is called _______.

A

[tachycardia]

209
Q

Fill in the blank: A heartbeat that is too slow is called _______.

A

[bradycardia]

210
Q

What are the potential outcomes of fibrillation?

A
  • Chest pain
  • Fainting
  • Lack of pulse
  • Death
211
Q

Describe the function of the sinoatrial node.

A

It acts as the natural pacemaker of the heart, initiating the heartbeat.

212
Q

Give one possible cause of an ECG which has a QRS complex that is not as high as normal.

A

Muscle damage or poor electrical conduction.

213
Q

What happens to breathing rate and heart rate when you exercise?

A

They increase to supply more oxygen and remove carbon dioxide

This increase is due to the muscles contracting more frequently and using more energy.

214
Q

What are the two main functions of increased breathing during exercise?

A
  • Obtain more oxygen
  • Remove more carbon dioxide
215
Q

What is the role of the heart rate during exercise?

A

To deliver oxygen and glucose to muscles faster and remove extra carbon dioxide

216
Q

Which part of the brain controls breathing rate?

A

The medulla oblongata

217
Q

What are the two ventilation centres in the medulla oblongata?

A
  • Inspiratory centre
  • Expiratory centre
218
Q

What does the inspiratory centre do?

A

Sends nerve impulses to intercostal and diaphragm muscles to contract

219
Q

What is the effect of the inspiratory centre on lung volume and pressure?

A

Increases lung volume, which lowers pressure in the lungs

220
Q

How does air enter the lungs?

A

Due to the pressure difference between the lungs and the air outside

221
Q

What stimulates the stretch receptors in the lungs?

A

Inflation of the lungs

222
Q

What happens when the stretch receptors are stimulated?

A

They send nerve impulses back to the medulla oblongata, inhibiting the inspiratory centre

223
Q

What does the expiratory centre do when it is no longer inhibited?

A

Sends nerve impulses to the diaphragm and intercostal muscles to relax

224
Q

What is the result of the diaphragm and intercostal muscles relaxing?

A

Lungs deflate, expelling air

225
Q

Fill in the blank: The ventilation centre can also be called the _______.

A

[respiratory centre]

226
Q

True or False: The inspiratory centre inhibits the expiratory centre.

A

True

227
Q

What happens to the cycle of breathing after the lungs deflate?

A

The stretch receptors become inactive, allowing the inspiratory centre to function again

228
Q

What happens to the level of carbon dioxide (CO2) in the blood during exercise?

A

The level of carbon dioxide (CO2) in the blood increases

This increase decreases the pH of the blood.

229
Q

What are chemoreceptors?

A

Chemoreceptors are receptors that sense chemicals

They are located in the medulla oblongata and in the aortic and carotid bodies.

230
Q

What effect do chemoreceptors have when they detect a decrease in blood pH?

A

They send nerve impulses to the medulla oblongata

This results in more frequent nerve impulses to the intercostal muscles and diaphragm.

231
Q

What is the primary function of the ventilation centre?

A

The ventilation centre controls the rate of breathing

It is also known as the respiratory centre.

232
Q

What is the definition of ventilation rate?

A

Ventilation rate is the volume of air breathed in or out in a period of time, e.g., a minute.

233
Q

How does exercise affect ventilation rate?

A

Ventilation rate increases during exercise

This is due to an increase in both breathing rate and depth.

234
Q

Fill in the blank: The carotid arteries carry blood to the _______.

A

brain

235
Q

What happens to the CO2 level during increased breathing rate and depth?

A

The CO2 level drops

This occurs as extra O2 is supplied for the muscles.

236
Q

What triggers exhalation following inhalation?

A

Stretch receptors in the lungs

They respond to lung expansion and signal for exhalation.

237
Q

True or False: The intercostal muscles contract during inhalation.

A

True

238
Q

What is the expected effect of adding dilute carbonic acid to the blood in the coronary artery of an anaesthetised animal?

A

The animal’s breathing rate would increase

This is due to the increased CO2 levels in the blood.

239
Q

List the components of the ventilation rate that increase during exercise.

A
  • Breathing rate
  • Depth of breathing
240
Q

What happens to the breathing rate after the pH of the blood returns to normal?

A

Breathing rate decreases

241
Q

What part of the brain controls the heart rate?

A

The medulla oblongata

The cardiovascular control centre in the medulla oblongata manages heart rate unconsciously.

242
Q

What is the role of the sinoatrial node (SAN) in heart function?

A

The SAN generates electrical impulses that cause the atria to contract, setting the rhythm of the heartbeat.

243
Q

What types of receptors detect stimuli in the blood related to heart rate?

A

Pressure receptors (baroreceptors) and chemical receptors (chemoreceptors)

Baroreceptors are located in the aortic and carotid bodies, while chemoreceptors monitor oxygen, carbon dioxide, and pH levels.

244
Q

True or False: The sympathetic nervous system decreases heart rate.

A

False

The sympathetic nervous system prepares the body for action and increases heart rate during exercise.

245
Q

What neurotransmitter is secreted by parasympathetic neurones to decrease heart rate?

A

Acetylcholine

246
Q

Fill in the blank: Baroreceptors detect ______ blood pressure.

A

high or low

247
Q

What is the response of the SAN when high blood pressure is detected?

A

The SAN fires impulses less frequently to slow heart rate and reduce blood pressure back to normal.

248
Q

What happens when chemoreceptors detect low blood oxygen levels?

A

The SAN fires impulses more frequently to increase heart rate and return oxygen levels back to normal.

249
Q

How does the cardiovascular control centre respond to low blood pressure?

A

It sends impulses along sympathetic neurones, secreting noradrenaline to increase heart rate.

250
Q

List the factors that chemoreceptors monitor in the blood.

A
  • Oxygen level
  • Carbon dioxide level
  • pH
251
Q

What is the primary function of the cardiovascular control centre?

A

To process information from receptors and regulate heart rate through sympathetic and parasympathetic impulses.

252
Q

Fill in the blank: The parasympathetic nervous system is known as the ‘______ and digest’ system.

A

rest

253
Q

What effect does exercise have on heart rate?

A

Increases heart rate

254
Q

What is the function of baroreceptors in relation to blood pressure?

A

They detect high and low blood pressure.

255
Q

True or False: The medulla oblongata is responsible for conscious control of heart rate.

A

False

Heart rate is controlled unconsciously by the cardiovascular control centre in the medulla oblongata.

256
Q

What is the equation for calculating cardiac output?

A

Cardiac output (cm³ min⁻¹) = heart rate (beats per minute) x stroke volume (cm³)

Cardiac output increases with exercise due to increased heart rate and stroke volume.

257
Q

Define stroke volume.

A

The volume of blood pumped by one ventricle each time it contracts

Stroke volume is measured in cm³.

258
Q

What happens to cardiac output during exercise?

A

Cardiac output increases due to increased heart rate and stroke volume

This change supports the body’s increased demand for oxygen.

259
Q

Fill in the blank: Stroke volume (cm³) = _______.

A

cardiac output (cm³ min⁻¹) / heart rate (beats per minute)

260
Q

What is the heart rate of a swimmer before swimming 50 m?

A

65 bpm

This is the heart rate at rest.

261
Q

Calculate the cardiac output before swimming for a swimmer with a heart rate of 65 bpm and a stroke volume of 70 cm³.

A

4550 cm³ min⁻¹

Calculation: 65 bpm x 70 cm³ = 4550 cm³ min⁻¹.

262
Q

What is the heart rate of the swimmer after swimming 50 m?

A

120 bpm

This represents the increased demand after exercise.

263
Q

What is the difference in cardiac output for the swimmer before and after the swim?

A

6250 cm³ min⁻¹

Calculation: 10,800 cm³ min⁻¹ (after) - 4550 cm³ min⁻¹ (before) = 6250 cm³ min⁻¹.

264
Q

What is the stroke volume of the swimmer after swimming?

A

90 cm³

Calculation: 10,800 cm³ min⁻¹ / 120 bpm = 90 cm³.

265
Q

Which type of receptors detect changes in blood pressure?

A

Baroreceptors

These receptors play a crucial role in regulating blood pressure.

266
Q

What effect do neurotransmitters released from parasympathetic neurones have on heart rate?

A

They decrease heart rate

This is part of the body’s response to rest.

267
Q

What neurotransmitter do sympathetic neurones release onto the SAN?

A

Norepinephrine

This neurotransmitter increases heart rate.

268
Q

True or False: Cardiac output decreases during exercise.

A

False

Cardiac output increases to meet the body’s higher oxygen demand.

269
Q

Before a race, a runner has a stroke volume of 72 cm³ and a cardiac output of 5420 cm³ min⁻¹. What is the runner’s heart rate before the race?

A

75 bpm

Calculation: 5420 cm³ min⁻¹ / 72 cm³ = 75 bpm.

270
Q

Explain how information about chemical changes in the blood are relayed to the brain during exercise.

A

Chemoreceptors detect changes and send signals to the brain, influencing heart rate and breathing

This involves a feedback loop that helps regulate physiological responses.

271
Q

Explain how increased activity of sympathetic neurones affects the runner’s heart rate when running.

A

It increases heart rate to supply more oxygen to muscles

This response is critical during physical exertion.

272
Q

What is tidal volume?

A

The volume of air in each breath, usually about 0.4 dm³

1 dm³ is equivalent to 1 litre.

273
Q

What does breathing rate refer to?

A

How many breaths are taken, usually measured per minute.

274
Q

What is oxygen consumption?

A

The volume of oxygen used by the body, often expressed as a rate.

275
Q

How is respiratory minute ventilation calculated?

A

Respiratory minute ventilation = tidal volume x breathing rate (breaths per minute).

276
Q

What is another term for respiratory minute ventilation?

A

Ventilation rate (per minute).

277
Q

What is a spirometer?

A

A machine that can give readings of tidal volume and measure breathing rate, oxygen consumption, and respiratory minute ventilation.

278
Q

How does a spirometer work?

A

A person breathes through a tube into an oxygen-filled chamber with a movable lid; movements are recorded by a pen on a rotating drum.

279
Q

What happens to the total volume of gas in a spirometer chamber over time?

A

It decreases because the exhaled air is a mixture of oxygen and carbon dioxide, with carbon dioxide absorbed by soda lime.

280
Q

How does exercise affect breathing parameters?

A

Exercise increases breathing rate, tidal volume, oxygen consumption, and respiratory minute ventilation.

281
Q

What is the procedure to investigate the effects of exercise using a spirometer?

A

1) Measure breathing at rest for one minute. 2) Exercise for two minutes. 3) Measure breathing again for one minute after exercise and compare recordings.

282
Q

Fill in the blank: The volume of gas breathed in or out in a minute is called _______.

A

respiratory minute ventilation.

283
Q

True or False: A spirometer can be used to measure only tidal volume.

A

False.

284
Q

What is tidal volume?

A

The volume of air in each breath, usually about 0.4 dm³.

Tidal volume is equivalent to 0.4 liters.

285
Q

How is breathing rate defined?

A

The number of breaths taken, usually measured in a minute.

286
Q

What does oxygen consumption refer to?

A

The volume of oxygen used by the body, often expressed as a rate.

287
Q

What is the formula for calculating respiratory minute ventilation?

A

Respiratory minute ventilation = tidal volume x breathing rate (breaths per minute).

288
Q

What is another term for respiratory minute ventilation?

A

Ventilation rate (per minute).

289
Q

What is residual air?

A

Air that cannot be expelled from the lungs.

290
Q

What is a spirometer?

A

A machine that measures tidal volume, breathing rate, oxygen consumption, and respiratory minute ventilation.

291
Q

How does a spirometer record breathing?

A

A pen attached to the lid of the chamber writes on a rotating drum, creating a spirometer trace.

292
Q

What happens to the total volume of gas in the spirometer chamber over time?

A

The total volume decreases as exhaled air is a mixture of oxygen and carbon dioxide, with carbon dioxide absorbed by soda lime.

293
Q

How does exercise affect breathing parameters?

A

Exercise increases breathing rate, tidal volume, oxygen consumption, and respiratory minute ventilation.

294
Q

What is the first step in using a spirometer to investigate the effects of exercise?

A

A person breathes into a spirometer for one minute at rest, and recordings are taken.

295
Q

What happens during the exercise phase of spirometer testing?

A

The person exercises, e.g. runs on a treadmill, for two minutes while the spirometer chamber is refilled with oxygen.

296
Q

What is compared after exercise in spirometer testing?

A

Recordings taken before and after exercise.

297
Q

Fill in the blank: Tidal volume is usually about ______ dm³.

A

0.4

298
Q

True or False: A spirometer can only measure tidal volume.

A

False

299
Q

What is the formula to calculate breathing rate from a spirometer trace?

A

Count the number of peaks in the trace in a minute.

300
Q

How is tidal volume determined from a spirometer trace?

A

Find the average difference in the volume of gas between each peak and trough on the trace.

301
Q

What does oxygen consumption represent in a spirometer trace?

A

Find the change in volume of gas in the spirometer (read values from the troughs).

302
Q

What is the tidal volume of a person at rest with a body mass of 60 kg?

A

0.4 dm³.

303
Q

What is the breathing rate of a person at rest?

A

12 breaths per minute.

304
Q

What is the rate of oxygen consumption at rest for a person with a body mass of 60 kg?

A

0.6 dm³ per minute.

305
Q

How do you calculate the rate of oxygen consumption per kg of body mass?

A

Divide the total oxygen consumption by body mass (60 kg).

306
Q

What is the formula for respiratory minute ventilation?

A

Tidal volume x Breathing rate.

307
Q

What is the respiratory minute ventilation for a person at rest with a tidal volume of 0.4 dm³ and a breathing rate of 12?

A

4.8 dm³ min⁻¹.

308
Q

True or False: During exercise, the body needs more oxygen and must remove more carbon dioxide.

A

True.

309
Q

What changes occur in breathing rate, tidal volume, and oxygen consumption during exercise?

A

All increase.

310
Q

What happens to breathing rate and tidal volume during recovery after exercise?

A

They return to rest levels.

311
Q

How does fitness training affect breathing rate at rest and during recovery?

A

Training decreases breathing rate both at rest and during recovery.

312
Q

What effect does fitness training have on tidal volume?

A

Training increases tidal volume.

313
Q

Fill in the blank: Training allows for _______ air to be taken in with each breath.

A

[more]

314
Q

How does fitness training impact the recovery rate of breathing rate and tidal volume?

A

They decrease faster due to training.

315
Q

What is the formula to calculate breathing rate from a spirometer trace?

A

Count the number of peaks in the trace in a minute.

316
Q

How is tidal volume determined from a spirometer trace?

A

Find the average difference in the volume of gas between each peak and trough on the trace.

317
Q

What does oxygen consumption represent in a spirometer trace?

A

Find the change in volume of gas in the spirometer (read values from the troughs).

318
Q

What is the tidal volume of a person at rest with a body mass of 60 kg?

A

0.4 dm³.

319
Q

What is the breathing rate of a person at rest?

A

12 breaths per minute.

320
Q

What is the rate of oxygen consumption at rest for a person with a body mass of 60 kg?

A

0.6 dm³ per minute.

321
Q

How do you calculate the rate of oxygen consumption per kg of body mass?

A

Divide the total oxygen consumption by body mass (60 kg).

322
Q

What is the formula for respiratory minute ventilation?

A

Tidal volume x Breathing rate.

323
Q

What is the respiratory minute ventilation for a person at rest with a tidal volume of 0.4 dm³ and a breathing rate of 12?

A

4.8 dm³ min⁻¹.

324
Q

True or False: During exercise, the body needs more oxygen and must remove more carbon dioxide.

A

True.

325
Q

What changes occur in breathing rate, tidal volume, and oxygen consumption during exercise?

A

All increase.

326
Q

What happens to breathing rate and tidal volume during recovery after exercise?

A

They return to rest levels.

327
Q

How does fitness training affect breathing rate at rest and during recovery?

A

Training decreases breathing rate both at rest and during recovery.

328
Q

What effect does fitness training have on tidal volume?

A

Training increases tidal volume.

329
Q

Fill in the blank: Training allows for _______ air to be taken in with each breath.

A

[more]

330
Q

How does fitness training impact the recovery rate of breathing rate and tidal volume?

A

They decrease faster due to training.

331
Q

What is homeostasis?

A

The maintenance of a constant internal environment in the body.

332
Q

What mechanisms are used to reduce body temperature?

A
  • Sweating
  • Vasodilation
  • Hairs lie flat
333
Q

What is the function of sweating in temperature regulation?

A

More sweat is secreted when the body’s too hot, and its evaporation cools the skin.

334
Q

What occurs during shivering?

A

Muscles contract in spasms, producing more heat from increased respiration.

335
Q

How do hairs contribute to temperature regulation?

A

Hairs stand up to trap air for insulation when cold and lie flat to reduce insulation when hot.

336
Q

What is vasodilation?

A

The dilation of arterioles near the skin surface, increasing blood flow and heat loss.

337
Q

What role do hormones play in temperature regulation?

A

Hormones like adrenaline and thyroxine increase metabolism, producing more heat.

338
Q

What is vasoconstriction?

A

The constriction of arterioles near the skin surface, reducing blood flow and heat loss.

339
Q

Which part of the brain controls body temperature?

A

The hypothalamus.

340
Q

How do thermoreceptors contribute to thermoregulation?

A

They send impulses to the hypothalamus regarding temperature changes.

341
Q

What is thermoregulation?

A

The control of body temperature.

342
Q

Fill in the blank: The normal body temperature for mammals is ______.

A

37 °C

343
Q

What happens when body temperature rises?

A
  • Vasodilation
  • Sweating
  • Hairs lie flat
  • No shivering
  • No adrenaline or thyroxine released
344
Q

What happens when body temperature falls?

A
  • Vasoconstriction
  • Much less sweating
  • Hairs stand upright
  • Shivering
  • Adrenaline and thyroxine released
345
Q

True or False: Exercise decreases body temperature.

A

False

346
Q

How do steroid hormones affect transcription factors?

A

They bind to DNA to alter gene transcription.

347
Q

What is the role of the thyroid hormone receptor?

A

It binds to DNA to decrease transcription of a gene coding for a protein that increases metabolic rate.

348
Q

What happens when thyroxine is released at cold temperatures?

A

It binds to the thyroid hormone receptor, increasing transcription and metabolic rate.

349
Q

How do protein hormones affect transcription factors?

A

They bind to cell membrane receptors, activating messenger molecules that influence transcription factors.

350
Q

What triggers a cascade of reactions inside the cell when a protein hormone binds to a receptor?

A

Activation of messenger molecules and protein kinases.

351
Q

Describe what is meant by a positive feedback mechanism.

A

A process that amplifies change, moving away from a set point.

352
Q

Give two mechanisms that can reduce body temperature.

A
  • Sweating
  • Vasodilation
353
Q

What effect does a very high body temperature have on metabolic reactions?

A

It can lead to denaturation of enzymes and disrupt normal metabolic processes.

354
Q

How does homeostasis work like a teacher?

A

It corrects deviations from a set point to maintain balance.

355
Q

What is negative feedback in homeostasis?

A

A response mechanism that counteracts changes in the internal environment.

356
Q

What is the relationship between physical activity and BMI according to the data?

A

The percentage of people who do very little physical activity increases as BMI increases, while the percentage of people who do ≥ 5 days of physical activity per week decreases as BMI increases.

BMI is used as an index of obesity, with a BMI of ≥ 30 kg/m² classed as obese.

357
Q

What correlation is observed between physical activity and obesity?

A

There’s a correlation between doing less physical activity and being obese, but causation cannot be established.

Other factors may influence this correlation.

358
Q

What was the age range of the men involved in the CHD study?

A

The men were aged 71-93 years at the start of the follow-up period.

359
Q

What trend was observed in the incidence of CHD based on distance walked daily?

A

Men who walked less each day had a higher incidence of CHD than those who walked more.

The study only involved elderly men and only looked at walking.

360
Q

How does physical activity relate to the prevalence of Type 2 diabetes according to the survey?

A

Diabetes is more prevalent in inactive than active people, regardless of BMI.

There is also a correlation between increasing BMI and increasing prevalence of diabetes.

361
Q

What is the effect of too much exercise on joint health?

A

The percentage of male former elite athletes admitted to hospital for osteoarthritis is more than twice that of healthy men (5.9% compared to 2.6%).

Endurance athletes had the highest admission rates.

362
Q

What conclusion can be drawn about elite athletes and respiratory illnesses?

A

There’s a correlation between being an elite athlete and a higher number of respiratory illnesses compared to recreational athletes and sedentary controls.

Elite athletes may be exposed to more infections during competitions.

363
Q

Define correlation in the context of exercise and health.

A

A correlation indicates a relationship between two variables, but it does not imply causation.

364
Q

Fill in the blank: A BMI of ≥ _______ kg/m² is classed as obese.

A

30

365
Q

True or False: The study on CHD can conclude that increased physical activity directly reduces the risk of CHD.

A

False

366
Q

What key factor should be considered when interpreting data on exercise and health?

A

Correlation does not imply causation.

367
Q

What is keyhole surgery?

A

A way of doing surgery without making a large incision in the skin.

Surgeons make a much smaller incision and insert a tiny video camera and specialized medical instruments.

368
Q

What are the advantages of keyhole surgery over regular surgery?

A
  • Less blood loss
  • Less scarring of the skin
  • Less pain post-operation
  • Quicker recovery
  • Shorter hospital stay

Keyhole surgery involves less damage to the body.

369
Q

What is a common sports injury related to the cruciate ligaments?

A

Damage to the cruciate ligaments in the knee.

Cruciate ligaments connect the thigh bone to the lower leg bone.

370
Q

What is a prosthesis?

A

An artificial device used to replace missing or damaged body parts.

Prostheses can replace whole limbs or parts of limbs.

371
Q

How can prostheses assist athletes?

A

They allow people with disabilities or injuries to participate in sports.

For example, prosthetic legs (blades) allow individuals without legs to run.

372
Q

What is the role of electronic devices in some prostheses?

A

They operate the prosthesis by picking up information from the nervous system.

This allows users to move their prosthetic fingers, for example.

373
Q

What are performance-enhancing drugs?

A

Drugs that improve a person’s athletic performance.

Examples include anabolic steroids, stimulants, and narcotic analgesics.

374
Q

What are anabolic steroids used for?

A

To increase strength, speed, and stamina by increasing muscle size.

They also increase aggression.

375
Q

What are the arguments against using performance-enhancing drugs?

A
  • Some drugs are illegal
  • Competitions become unfair
  • Serious health risks
  • Athletes may be uninformed about risks

Side effects include high blood pressure and heart problems.

376
Q

What are the arguments in favor of using performance-enhancing drugs?

A
  • Individual choice
  • Drug-free sport isn’t fair due to inequalities
  • Higher competition levels may require drug use

Different athletes have varying access to resources.

377
Q

Fill in the blank: Keyhole surgery involves making a _______ incision.

A

smaller

378
Q

True or False: Performance-enhancing drugs are allowed in most sports.

A

False

379
Q

What is the purpose of a knee joint replacement?

A

To replace damaged cartilage and bone in the knee.

It helps individuals with serious knee issues participate in low-impact sports.

380
Q

What is the typical procedure for fixing damaged cruciate ligaments?

A

Removal of the damaged ligament and replacement with a graft.

The graft may come from the patient’s own tendon or a donor.

381
Q

List three types of performance-enhancing drugs.

A
  • Anabolic steroids
  • Stimulants
  • Narcotic analgesics
382
Q

How does a prosthetic joint help individuals with knee problems?

A

It allows movement and participation in low-impact sports.

Cushioning in the joint reduces impact on the knee.

383
Q

What is a stimulus?

A

Any change in the internal or external environment.

384
Q

How do animals increase their chances of survival?

A

By responding to changes in their external and internal environment.

385
Q

What are receptors?

A

Cells or proteins on cell surface membranes that detect stimuli.

386
Q

What are effectors?

A

Cells that bring about a response to a stimulus, producing an effect.

387
Q

Name two types of effectors.

A
  • Muscle cells
  • Gland cells (e.g., pancreas)
388
Q

What is the nervous system made up of?

A

A complex network of cells called neurones.

389
Q

What are the three main types of neurones?

A
  • Sensory neurones
  • Motor neurones
  • Relay neurones
390
Q

What do sensory neurones do?

A

Transmit electrical impulses from receptors to the central nervous system (CNS).

391
Q

What do motor neurones do?

A

Transmit electrical impulses from the CNS to effectors.

392
Q

What do relay neurones do?

A

Transmit electrical impulses between sensory neurones and motor neurones.

393
Q

What happens when an electrical impulse reaches the end of a neurone?

A

Neurotransmitters carry the information across to the next neurone.

394
Q

What is the CNS responsible for?

A

Processing information and sending impulses along motor neurones to effectors.

395
Q

What is the response of the eyes to dim light?

A

Radial muscles in the iris contract to dilate pupils.

396
Q

What is the response of the eyes to bright light?

A

Circular muscles in the iris contract to constrict pupils.

397
Q

What is the hormonal system made up of?

A

Glands and hormones.

398
Q

What is a gland?

A

A group of cells that are specialised to secrete a useful substance, such as a hormone.

399
Q

What are hormones?

A

Chemical messengers that are often proteins or peptides.

400
Q

How are hormones secreted?

A

When a gland is stimulated by a change in concentration of a specific substance or by electrical impulses.

401
Q

How do hormones travel in the body?

A

They diffuse directly into the blood and are taken around the body by the circulatory system.

402
Q

What are target cells?

A

Cells that have specific receptors for a hormone, allowing them to respond to that hormone.

403
Q

What is the effect of glucagon released by the pancreas?

A

Target cells in the liver convert glycogen into glucose, increasing blood glucose concentration.

404
Q

True or False: Nervous communication uses electrical impulses.

A

True.

405
Q

True or False: Hormonal communication has a faster response than nervous communication.

A

False.

406
Q

List three differences between nervous and hormonal communication.

A
  • Nervous communication uses electrical impulses, hormonal communication uses chemicals
  • Nervous communication has a faster response, hormonal communication is slower
  • Nervous communication is localized, hormonal communication is widespread
407
Q

What are receptors specific to?

A

One kind of stimulus

Receptors detect specific stimuli such as light, pressure, or glucose concentration.

408
Q

What are photoreceptors?

A

Light receptors in the eye

Photoreceptors include rods and cones that detect light.

409
Q

What happens to the cell membrane when a receptor is in resting state?

A

It is polarized

A difference in charge exists between the inside and outside of the cell.

410
Q

What is the voltage across the membrane called?

A

Potential difference

It is generated by ion pumps and ion channels.

411
Q

What triggers an action potential?

A

A sufficient change in potential difference

The action potential is an electrical impulse along a neurone.

412
Q

What are the two types of photoreceptors in the human eye?

A

Rods and cones

Rods are for black and white vision, while cones are for color vision.

413
Q

Where are rods mainly found?

A

In the peripheral parts of the retina

Cones are packed in the fovea.

414
Q

What type of vision do rods provide?

A

Monochromatic vision

Rods give information only in black and white.

415
Q

What do cones provide?

A

Trichromatic vision

Cones enable color vision and are sensitive to red, green, and blue light.

416
Q

What is the blind spot?

A

Where the optic nerve leaves the eye

It lacks photoreceptor cells, making it not sensitive to light.

417
Q

Fill in the blank: Light-sensitive pigments are found in _______.

A

Photoreceptors

These pigments are crucial for detecting light.

418
Q

What happens to rhodopsin when it is stimulated by light?

A

It breaks apart into retinal and opsin

This process is known as bleaching.

419
Q

What is hyperpolarization in rod cells?

A

When the inside of the cell becomes more negative than the outside

This occurs when sodium channels close after light stimulation.

420
Q

What effect does hyperpolarization have on neurotransmitter release?

A

Stops neurotransmitter release

This prevents inhibition of the bipolar neurone.

421
Q

True or False: Bipolar neurones are inhibited when it is dark.

A

True

In darkness, bipolar neurones are inhibited due to neurotransmitter release.

422
Q

What connects photoreceptors to the optic nerve?

A

Bipolar neurones

These neurones carry nerve impulses from photoreceptors to the brain.

423
Q

What is the role of sodium ion channels in rod cells?

A

They control the movement of sodium ions in and out of rod cells

Sodium channels are crucial for the depolarization and hyperpolarization processes.

424
Q

What is the basic structure of all neurones?

A

All neurones have a cell body with a nucleus and cytoplasm.

425
Q

What are the three different types of neurones?

A
  • Motor Neurones
  • Sensory Neurones
  • Relay Neurones
426
Q

What is the function of motor neurones?

A

Carry nerve impulses from the central nervous system (CNS) to effector cells.

427
Q

What is unique about sensory neurones?

A

One long dendron carries nerve impulses from receptor cells to the cell body.

428
Q

What is the role of relay neurones?

A

Carry nerve impulses from sensory neurones to motor neurones.

429
Q

What does it mean for a neurone’s cell membrane to be polarised at rest?

A

The outside of the membrane is positively charged compared to the inside.

430
Q

What is the resting potential of a neurone?

A

About -70 mV.

431
Q

How is the resting potential created and maintained?

A

By sodium-potassium pumps and potassium ion channels in a neurone’s membrane.

432
Q

What is the function of sodium-potassium pumps?

A

Move three sodium ions out and two potassium ions in using active transport.

433
Q

What happens during depolarisation of a neurone?

A

Sodium ions diffuse into the neurone, causing the membrane potential to become less negative.

434
Q

What is the peak membrane potential during action potential?

A

Around +30 mV.

435
Q

What occurs after depolarisation?

A

Potassium ion channels open, allowing potassium ions to diffuse out.

436
Q

What is hyperpolarisation?

A

When the membrane potential becomes more negative than the resting potential.

437
Q

What resets the ion channels after an action potential?

A

The sodium-potassium pump returns the membrane to resting potential.

438
Q

Fill in the blank: The change in potential across a neurone membrane during an action potential is called _______.

A

depolarisation

439
Q

True or False: The neurone cell membrane can be excited again immediately after an action potential.

A

False

440
Q

What is the refractory period in neurones?

A

The time during which the neurone cannot be excited again.

441
Q

What happens during repolarisation?

A

The neurone returns to its resting potential after depolarisation.

442
Q

What is the role of potassium ion channels during an action potential?

A

Allow potassium ions to diffuse out of the neurone.

443
Q

What is an action potential?

A

A rapid change in membrane potential that propagates along the neurone.

444
Q

What is the effect of the sodium ion electrochemical gradient?

A

Creates a difference in charge across the neurone’s membrane.

445
Q

What happens when an action potential occurs in a neurone?

A

Some sodium ions enter the neurone and diffuse sideways, causing sodium ion channels in the next region to open.

446
Q

How does the action potential move along the neurone?

A

As a wave of depolarisation.

447
Q

What is the refractory period?

A

A time during which ion channels are recovering and cannot be opened, preventing overlap of action potentials.

448
Q

What effect does the refractory period have on action potentials?

A

It ensures action potentials are discrete and unidirectional.

449
Q

What happens when a bigger stimulus is applied to a neurone?

A

It causes action potentials to fire more frequently, but does not increase the size of the action potential.

450
Q

What is the role of local anaesthetics in nerve conduction?

A

They bind to sodium ion channels, preventing sodium ions from entering the neurones and stopping action potentials.

451
Q

What is a myelinated neurone?

A

A neurone that has a myelin sheath, which is an electrical insulator made of Schwann cells.

452
Q

What are the nodes of Ranvier?

A

Bare membrane regions between Schwann cells where sodium ion channels are concentrated.

453
Q

What is saltatory conduction?

A

The process where depolarisation occurs only at the nodes of Ranvier, allowing the impulse to ‘jump’ from node to node.

454
Q

How does conduction velocity differ between myelinated and non-myelinated neurones?

A

Impulses travel faster in myelinated neurones than in non-myelinated neurones.

455
Q

Fill in the blank: The speed at which an impulse moves along a neurone is known as the _______.

A

[conduction velocity]

456
Q

True or False: Action potentials can overlap due to the refractory period.

A

False.

457
Q

What is the function of Schwann cells on a neurone?

A

To form the myelin sheath, which insulates the neurone.

458
Q

What is the primary effect of multiple sclerosis on action potential transmission?

A

It damages the myelin sheaths of neurones, affecting the speed and efficiency of action potentials.

459
Q

What is a synapse?

A

A synapse is the junction between a neurone and another neurone, or between a neurone and an effector cell, e.g. a muscle or gland cell.

460
Q

What is the tiny gap between the cells at a synapse called?

A

The synaptic cleft.

461
Q

What does the presynaptic neurone contain that is crucial for neurotransmitter release?

A

Synaptic vesicles filled with neurotransmitters.

462
Q

How do neurotransmitters affect the postsynaptic membrane?

A

They bind to specific receptors, which may trigger an action potential, cause muscle contraction, or stimulate hormone secretion.

463
Q

True or False: Synapses allow impulses to travel in both directions.

A

False.

464
Q

What happens to neurotransmitters after they have triggered a response?

A

They are removed from the cleft, either taken back into the presynaptic neurone or broken down by enzymes.

465
Q

Name two examples of neurotransmitters.

A
  • Acetylcholine
  • Dopamine
466
Q

What triggers the influx of calcium ions into the synaptic knob?

A

An action potential arriving at the synaptic knob.

467
Q

What is the process called when synaptic vesicles release neurotransmitters into the synaptic cleft?

A

Exocytosis.

468
Q

What effect does the influx of sodium ions into the postsynaptic membrane have?

A

It causes depolarisation, which can generate an action potential if the threshold is reached.

469
Q

What is synaptic divergence?

A

When one neurone connects to many neurones, allowing information to be dispersed to different parts of the body.

470
Q

What is synaptic convergence?

A

When many neurones connect to one neurone, allowing information to be amplified.

471
Q

Fill in the blank: Summation is where the effect of neurotransmitter released from many neurones, or one neurone that’s stimulated a lot in a short period of time, is ______.

A

[added together]

472
Q

What role do synaptic knobs play in neurotransmitter release?

A

They contain lots of mitochondria that produce ATP, needed for active transport and the movement of vesicles.

473
Q

What is the primary way plants respond to stimuli?

A

By regulating their growth towards or away from stimuli.

474
Q

What is a tropism?

A

The response of a plant to a directional stimulus.

475
Q

What is a positive tropism?

A

Growth towards the stimulus.

476
Q

What is a negative tropism?

A

Growth away from the stimulus.

477
Q

What is phototropism?

A

The growth of a plant in response to light.

478
Q

In phototropism, which part of the plant is positively phototropic?

A

Shoots.

479
Q

In phototropism, which part of the plant is negatively phototropic?

A

Roots.

480
Q

What is geotropism?

A

The growth of a plant in response to gravity.

481
Q

In geotropism, which part of the plant is negatively geotropic?

A

Shoots.

482
Q

In geotropism, which part of the plant is positively geotropic?

A

Roots.

483
Q

How do plants respond to stimuli without a nervous or circulatory system?

A

Using growth factors.

484
Q

What are growth factors?

A

Chemicals that speed up or slow down plant growth.

485
Q

Where are growth factors produced in a plant?

A

In the growing regions such as shoot tips and leaves.

486
Q

What is the role of auxins in plants?

A

Stimulate the growth of shoots by cell elongation.

487
Q

What effect do high concentrations of auxins have on roots?

A

Inhibit growth.

488
Q

Name two other plant growth factors besides auxins.

A
  • Gibberellins
  • Cytokinins.
489
Q

What is the function of gibberellins?

A

Stimulate flowering and seed germination.

490
Q

What is the function of cytokinins?

A

Stimulate cell division and cell differentiation.

491
Q

What does ethene do for plants?

A

Stimulates fruit ripening and flowering.

492
Q

What is the role of abscisic acid (ABA) in plants?

A

Involved in leaf fall.

493
Q

What is Indoleactic Acid (IAA)?

A

An important auxin that affects plant growth.

494
Q

How does IAA move within the plant?

A

By diffusion, active transport over short distances, and via the phloem over longer distances.

495
Q

What happens to IAA during phototropism?

A

Moves to the shaded parts of the shoots, causing uneven growth.

496
Q

What are phytochromes?

A

Photoreceptors that detect light in plants.

497
Q

What states do phytochromes exist in?

A
  • P_r (absorbs red light)
  • P_fr (absorbs far-red light).
498
Q

What effect does red light have on phytochromes?

A

Converts P_r to P_fr.

499
Q

What effect does far-red light have on phytochromes?

A

Converts P_fr to P_r.

500
Q

How do phytochromes influence flowering in plants?

A

High levels of P_fr stimulate flowering.

501
Q

Fill in the blank: _______ is a growth response of a plant to gravity.

A

Geotropism

502
Q

True or False: Roots grow upwards in response to gravity.

A

False.

503
Q

What do plants use to detect the amount of daylight?

A

Phytochromes.

504
Q

During which season do some plants flower when there are long days?

A

Summer.

Biology Edexcel Sophie (8 decks)

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