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biology > Topic 7 - Run For Your Life > Flashcards

Topic 7 - Run For Your Life Flashcards

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1
Q

myogenic meaning

A

the heart has the ability to initiate its own contractions

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2
Q

tendon definition

A

non-elastic tissue which connects muscles to bones

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3
Q

ligaments definition

A

elastic tissue that joins bones to bones and determines amount of movement possible at a joint

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4
Q

joints definition

A

the area where two bones are attached for the purpose of permitting body parts to move, made of fibrous connective tissue and cartilage

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5
Q

skeletal muscles definition

A

muscles attached to bones, arranged in antagonistic pairs

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6
Q

antagonistic muscle pairs

A
  • pairs of muscles which pull in opposite directions: as one muscle contracts the other relaxes
  • extensors act to straighten the join, flexors bend the joint
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7
Q

disadvantages of too much exercise

A
  • wear and tear on joints leads to joint damage
  • suppression of the immune system leads to increased risk of infection
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8
Q

disadvantages of too little exercise

A
  • risk of obesity
  • increased risk of CVD
  • increases risk of diabetes
  • suppression of the immune system
  • increased levels of LDL’s
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9
Q

what is keyhole surgery

A

a non-invasive method which uses fibre optics to repair damaged joints quickly
- much cheaper and recovery time is shorter

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10
Q

what is a prosthesis

A
  • an artificial body part which enables those with injuries to regain appearance or function of a particular body part
  • can be connected internally or externally
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11
Q

homeostasis definition

A

the control of internal conditions such as temperature

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12
Q

what is aerobic respiration

A

the splitting of a respiratory substrate reuniting hydrogen with atmospheric oxygen to release large amounts of energy and co2 as a waste product

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13
Q

what are the four stages of respiration

A

glycolysis
link reaction
kreb’s cycle
oxidative phosphorylation

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14
Q

what are slow and fast twitch fibres adapted for

A

slow = specialised for slow contractions and are adapted to long periods of exercise
fast = adapted for rapid release of energy during intense exercise: contractions are intense and in short bursts

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15
Q

what is oxidative phosphorylation

A

the process in which ATP is synthesised via chemiosmosis in the electron transport train in mitochondria. this generates the majority of ATP in aerobic respiration

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16
Q

aerobic respiration equation

A

glucose + oxygen = carbon dioxide + water + energy

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17
Q

structure of mitochondria

A

mitochondria have two phospholipid membranes:
1. outer membrane which is smooth and permeable to some small molecules
2. inner membrane which is folded into cristae and less permeable. this is the site of electron transport chain and location of ATP synthase enzyme.

inter membrane space: has a low pH due to the high conc of protons. the conc gradient across the inner membrane is formed during oxidative phosphorylation and is essential for ATP synthesis

the matrix: is an aqueous solution within the inner membranes of the mitochondrion. contains ribosomes, enzymes and circular mitochondrial DNA for the mitochondria to function

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18
Q

where do the four stages of respiration take place

A
  1. glycolysis: cell cytoplasm
  2. link reaction: matrix of mitochondria
  3. krebs cycle: matrix of mitochondria
  4. oxidative phosphorylation: inner membrane of mitochondria
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19
Q

what does anaerobic respiration not involve?

A

link reaction, krebs cycle or oxidative phosphorylation

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20
Q

how can lactic acid be broken down

A
  1. cells can convert lactic acid back to pyruvate to be used in the krebs cycle
    - this requires extra oxygen (known as oxygen debt). this is why we breathe deeper and faster after exercise
  2. liver cells can convert lactic acid back to glucose for use in respiration or storage
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21
Q

explain antagonistic muscle action with biceps and triceps

A
  1. when biceps contract, triceps relax. the arm flexes around the elbow joint. the bicep is bending a joint during contraction so is known as the flexor
  2. when triceps contract, biceps relax. arm flexes around joint. the tricep straightens the joint during a contraction and so is known as the extensor
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22
Q

explain structure of muscle fibre

A

cell membrane of muscle fibre is called the SARCOLEMMA

bits of the sarcolemma fold inwards and stick into the SARCOPLASM (cytoplasm). these folds are called TRANSVERSE TUBULES and help spread electrical impulses.

a network of internal membranes called the SARCOPLASMIC RETICULUM store and release calcium ions for muscle contraction

muscle fibres have lots of mitochondria and contain many nuclei

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23
Q

explain the two components of myofibrils

A
  • contain thick myofilaments made of myosin
  • they are fibrous proteins with a globular head. fibrous proteins anchor molecule into thick filament
  • contain thin myofilaments made of actin
  • these are globular protein molecules. many actin molecules link together to form a chain. two actin twist together to form one filament.
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24
Q

what is the sliding filament theory

A

myosin and actin filaments slide over one another to make the sarcomeres contract.
the contraction of lots of sarcomeres means the myofibrils and muscle fibres contract
sarcomeres return to their original length as muscle relaxes

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25
Q

fast twitch muscle fibres properties

A
  • contract very quickly
  • used for fast movement
  • good for short bursts of speed and power
  • get tired very quickly
  • energy released quickly through anaerobic respiration using glycogen
  • whitish in colour as don’t have much myoglobin
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26
Q

slow twitch muscle fibre properties

A
  • contract slowly
  • used for posture
  • good for endurance activities
  • can work for long periods without tiring
  • energy released slowly through anaerobic respiration
  • reddish in colour as rich in myoglobin
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27
Q

give three examples of performance enhancing drugs

A
  1. anabolic steroids - increase strength, speed and stamina by increasing muscle size. may lead to organ damage and aggression
  2. stimulants - speed up reactions and reduce fatigue. may also lead to aggression
  3. narcotic analgesics - reduce pain, so injuries do not affect performance
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28
Q

ethical considerations of performance enhancing drugs

A

AGAINST:
1. many are illegal
2. competitions become unfair
3. health risks such as high blood pressure and heart issues
4. athletes may not be fully informed about health risks with these drugs

FOR:
1. freedom of choice
2. may help overcome inequalities within sport
3. many more athletes will be able to compete at a higher level

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29
Q

explain keyhole surgery advantages

A
  • patients lose less blood and have less scarring of the skin
  • usually less pain and quicker recovery time
  • shorter hospital stay
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30
Q

explain a prosthesis in a damaged knee joint

A
  1. metal device is inserted into the knee to replace damaged cartilage and bone
  2. knee joint and ends of leg bones are replaced to provide a smooth knee joint.
  3. plastic spacer is often inserted to provide cushioning
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31
Q

explain how muscles contract (the sliding filament theory)

A

use save my exams for this

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32
Q

cardiac output definition

A

the volume of blood that is pumped by the heart per unit of time

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33
Q

stroke volume definition

A

the volume of blood pumped out of the left ventricle during one cardiac cycle

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34
Q

what happens to cardiac output as someone exercises

A
  • increases
  • so blood supply can match increased metabolic demands of the cells
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35
Q

cardiac ouput equation

A

ca = heart rate x stroke volume

36
Q

explain the stages of electrical activity in the heart

A
  1. sinoatrial node initiates a wave of depolarisation that causes atria to contract
  2. AVN is stimulated and passes the stimulation along the bundle of His
  3. BOH divides into two conducting fibres, called Purkyne tissue, and carries the wave of excitation along them
  4. PF spread around the ventricles and initiate the depolarisation of the ventricles from the apex of the heart
  5. this makes the ventricles contract from the bottom upwards and blood is forced out of the ventricles into pulmonary artery and aorta
37
Q

why is homeostasis important

A
  1. temperature
    - ensures the maintenance of optimal conditions for enzyme action and cell function
  2. blood glucose
    - glucose is respired to produce ATP, thus the body needs to monitor blood glucose conc. this is done by the cells in the pancreas
  3. water
    - crucial amount of water in blood remains constant
    - kidneys are responsible for regulating water in blood
38
Q

what are the cooling mechanisms of the body

A
  1. vasodilation of the blood vessels that supply skin capillaries
    - one way to increase heat loss is to supply blood vessels with a greater volume of blood, which then loses heat to the environment
    - arteriole muscles relax, causing arterioles to dilate and allow more blood flow to capillaries in skin
  2. sweating
    -cools the skin by evaporation, heat energy converts liquid water into vapour
  3. flattening of hairs
    - stops hair forming an insulating layer of trapped air and allows air to circulate over skin
39
Q

what are the warming mechanisms of the body

A
  1. vasconstriction of blood vessels that supply skin capillaries
    - one way to increase heat loss is to supply blood vessels with less volume of blood, which then minimises heat loss to the environment
    - arteriole muscles contract, causing arterioles to contract and allow less blood flow to skin capillaries
  2. boosting metabolic rate
    - most metabolic reactions in the body are exothermic, thus produce heat
  3. shivering
  4. erection of hairs
    - forms an insulating layer over the skins surface
  5. less sweating
    - reduces amount of heat lost through evaporation
40
Q

what is the role of the hypothalamus in thermoregulation when body temp is too high

A
  • thermoreceptors in the hypothalamus and skin detect a change
  • heat loss centre in hypothalamus is stimulated
  • hypothalamus sends impulses to sweat glands
  • increased blood flow to the surface of skin by vasdilation
  • cooling mechanisms occur eg increases sweating
  • decrease in body temperature and metabolic rate
41
Q

difference between positive and negative feedback

A

Positive feedback occurs to increase the change or output
Negative feedback occurs to reduce the change or output

42
Q

how does negative feedback work

A
  • receptors detect any deviations in a factor from the normal range; this results in a corrective mechanism to return the factor back to its normal range
  • in a negative feedback loop there are usually two corrective mechanisms
    1. for when the factor becomes too low
    2. for when the factor becomes too high
  • the magnitude of the correction required to bring a factor back within its normal range is regulated by negative feedback
43
Q

how does positive feedback work

A

the original stimulus produces a response that causes the factor to deviate even more from the normal range
an example of this is the dilation of the cervix during labour

44
Q

the effects of hormones inside cells

A
  • hormones that can cross the cell membrane are able to enter the nucleus and bind to transcription factors
45
Q

explain an example of the effects of hormones inside the cells

A

hormonal regulation of body temperature:
1. at normal body temp a transcription factor known as the thyroid hormone receptor binds to a section of DNA at the start of a gene
2. the gene will not be expressed: it is switched off

  • in cold temperatures the body releases thyroxine which binds to the thyroid hormone receptor
  • this allows rna polymerase to bind to the start of the gene, the gene is then switched on and rate of expression increases
  • the protein which increases metabolic rate is quickly produced, leading to an increase in body temp
46
Q

how do hormones work from outside of cells

A
  • hormones that cannot cross the cell membrane bind to receptors in the cell membrane
  • this binding initiates a process that activates messenger molecules in the cytoplasm known as second messengers
  • this activated messenger activates proteins called protein kinases
  • active protein kinase enzymes trigger a chain of reaction, known as a cascade, inside the cell
  • the cascade may result in changes to the activity of transcription factors, affecting gene transcription
47
Q

what is the effect of dysfunctional cristae on the production of ATP

A
  • would produce less ATP
  • because there is a smaller surface area of the cristae
  • meaning there are fewer electron transport chains
48
Q

why can anaerobic respiration not be used for long periods of time

A

build up of lactic acid
which creates an oxygen debt
therefore only a small amount of ATP can be produced

49
Q

explain the role of carrier molecules in the electron transport chain

A
  • receive hydrogen from reduced NAD to allow reduced NAD to be oxidised
  • break hydrogen into protons and electrons
  • electrons transferred by a series of redox reactions
  • energy released is used to pump hydrogen ions into intermembranal space
50
Q

explain the role of oxygen in human respiration

A
  • final electron acceptor in the electron transport chain
  • to allow oxidative phosphorylation
  • ATP is synthesised
  • allow oxidation of reduced NAD
51
Q

what is the purpose of potassium hydroxide solution in a respirometer

A
  • to absorb co2
  • so that the volume of oxygen can be measured
52
Q

explain the role of the cruciate ligament

A
  • attaches bone to bone
  • allows movement and stability
53
Q

name three molecules needed for aerobic respiration that can move into the mitochondria

A
  • pyruvate
  • oxygen
  • reduced NAD
54
Q

The outer mitochondrial membrane is not permeable to hydrogen ions (H+)
Explain the importance of this feature of the membrane.

A
  • to stop H+ diffusing into cytoplasm
  • therefore maintaining a high concentration of H+ in the intermembrane space
  • so hydrogen ions can move down conc gradient
  • by chemiosmosis to make ATP
55
Q

how does the body accommodate to exercise

A
  • muscle contraction occurs more frequently, requiring more energy
  • rate of aerobic respiration increases to meet the increase in energy demand
  • the body increases the rate and depth of breathing which increases amount of oxygen entering lungs and blood, whilst removing more co2
  • body also increases heart rate which will transport o2 and glucose to the muscles much faster, whilst removing additional co2 produced due to increased rate of respiration
56
Q

what is breathing rate controlled by

A

ventilation centres in the medulla oblongata
- inspiratory centre controls movement of air into the lungs
- expiratory centre controls movement of air out of the lungs

57
Q

what effect does the inspiratory centre have on breathing

A
  • it sends nerve impulses along motor neurones to the intercostal muscles of the ribs and diaphragm muscles
  • these muscles contract and cause the volume of the chest to increase
  • this lowers the air pressure in the lungs
  • an impulse is sent to the expiratory centre to inhibit its action
  • due to difference in pressure, air flows into the lungs
  • stretch receptors in the lungs are stimulated as they fill with air
  • nerve impulses are sent to the medulla oblongata which will inhibit the inspiratory centre
58
Q

once the expiratory centre is no longer inhibited, what changes does it bring about

A
  • sends nerve impulses to the intercostal and diaphragm muscles
  • these muscles relax and cause the volume of the chest to decrease
  • this increases the air pressure in the lungs
  • due to higher pressure in the lungs, air flows out of the lungs
  • as lungs deflate, stretch receptors become inactive which means the inspiratory centre is no longer inhibited and the next breathing cycle will begin
59
Q

effect of exercise on the control of breathing

A
  • extra co2 that is produces due to the increase rate of respiration during exercise dissolves in the blood to form carbonic acid
  • this dissociates into hydrogen ions and hydrogencarbonate ions
  • the increase in H+ ions decreases the ph of the blood
  • this decrease in ph is detected by chemoreceptors
  • nerve impulse is sent to MO
  • MO sends more frequent nerve impulses to the intercostal and diaphragm muscles to increase rate and strength of contractions
  • this increases breathing rate and depth
    -therefore, more o2 enters the lungs, while more co2 can be exhaled
  • the decrease in co2 levels causes blood ph to return to normal, therefore breathing rate returns to normal
60
Q

how does the MO control heart rate

A
  • the cardiovascular control centre in the MO controls heart rate by controlling the rate at which the SAN generates electrical impulses
  • these impulses cause the atria to contract and therefore determines hearthbeat
61
Q

how do changes in the internal environment of the body change heart rate

A
  • changes act as a stimuli which is detected by baroreceptors and chemoreceptors
  • once stimulated, the receptors send impulses to the MO
  • the MO responds by sending impulses to the SAN along sympathetic or parasympathetic neurones
62
Q

explain sympathetic and parasympathetic neurones

A
  • sympathetic neurones increase the rate at which the SAN generates electrical impulses, thus speeding up heart rate
  • para does the opposite
63
Q

response to high blood pressure/ high blood o2, low co2, high blood ph

A
  • detected by baroreceptors which send impulses to the cardiovascular control centre
  • sends impulses along the parasympathetic neurones which secrete the neurotransmitter acetylcholine
  • acetylcholine binds to receptors on SAN causing it to fire less frequently
  • heart rate slows down
64
Q

response to low blood pressure

A
  • detected by baroreceptors which send impulses to the CCC
  • sends impulses along the sympathetic neurones which secrete the neurotransmitter noradrenaline
  • noradrenaline binds to receptors on SAN causing it to fire more frequently
  • heart rate speeds up
65
Q

response to low blood o2, high co2 and low ph levels

A
  • detected by chemoreceptors which send impulses to CCC
    -sends impulses along sympathetic neurones which secrete noradrenaline
  • noradrenaline binds to receptors on SAN causing it to fire more frequently
  • heart rate speeds up
66
Q

explain why it is necessary for cardiac output to increase during exercise

A
  • increase supply of oxygenated blood to muscles
  • to allow aerobic respiration
  • to provide more energy to meet the increased demands
67
Q

deduce how adrenaline can cause a change in heart rate.

A
  • adrenaline carried in the blood
  • acts on the SAN
  • increasing the frequency of impulses produced by the SAN
  • increasing the rate at which the heart contracts
68
Q

Explain the effect of exercise on the changes in oxygen consumption

A
  • exercise will increase oxygen consumption
  • because there is increased aerobic respiration
  • because more energy is needed by muscles
  • oxygen is required to convert lactic acid into glucose
69
Q

how to find respiratory minute volume and oygen consumption from a spirometer graph

A

RMV:
- find the difference in peak to trough volume
- find ventilation rate
- multiply tidal volume by ventilation rate
OC:
- difference in volume of one peak compared to a subsequent one

70
Q

Describe how the sinoatrial node (SAN) is involved in bringing about a change in heart rate
as the level of activity increases

A

more stimulation of the SAN from the sympathetic nervous system
causing more frequent waves of depolarisation from the SAN to atria
therefore more frequent contraction of atria

71
Q

explain how a gene can be expressed in some tissues but not in others

A
  • hormones bind to receptors found only in some tissues
  • regulating a transcription factor
  • transcription factor binds to the promotor region of the gene
  • switching on/off transcription
72
Q

how can transcription factors activate genes

A
  • hormones bind to receptors found only in some tissues
  • regulating a transcription factor
  • transcription factor binds to the promotor region of the gene
  • RNA polymerase binds to promotor region
  • transcription occurs for gene
73
Q

how can groups of cells produce the same enzyme?

A

genes can be activated or deactivated
these cells receive the same stimulus
all of these cell have the gene for the enzyme switched on
resulting in production of mRNA for the enzyme

74
Q

Describe how the concentration of calcium ions around the myofibrils is controlled.

A
  • released by sarcoplasmic reticulum
  • in response to an action potential
  • calcium ion channels open to allow calcium ions to enter the sarcoplasm
75
Q

Describe two structural differences between fast twitch muscle fibres and slow twitch
muscle fibres.

A
  • fast twitch have few mitochondria, slow twitch have many
  • fast twitch have few capillaries, slow twitch have many
76
Q

Explain how the structure of a muscle fibre is related to its specialised function.

A
  • sarcolemma contains voltage gated channels to allow depolarisation
  • many mitochondria for aer0bic respiration
  • presence of myofibrils
  • myofibrils allow contraction of muscle
77
Q

Explain what is meant by no significant difference at the 0.05 probability level

A
  • there is more than a 5% likelihood
  • the calculated t value is less than the critical value
78
Q

location of the SAN

A

right atrium

79
Q

describe how a muscle contracts

A
  • myosin heads bind to binding sites
  • myosin changes shape
  • actin filaments pulled over the myosin
  • muscle fibres shorten
  • atp hydrolysed into ADP and Pi
80
Q

Deduce how athletes with transtibial amputations are able to move their prosthetic limbs during a race

A

muscles are still attached to bones in the lower leg and the prosthetic limb is attached to the lower leg

81
Q

similarities between slow and fast twitch muscle fibres

A

both produce energy and help in movement
both generate force
both present in relatively equal amounts

82
Q

Elite sprinters tend to be bulkier and more muscular than long distance runners because….

A
  • elite sprinters have a greater percentage of fast twitch muscle fibres
  • fast twitch muscle fibres have thicker diameter
83
Q

explain antagonistic muscle action

A

As one muscle contracts the other muscle relaxes or lengthens; [1 mark]
The flexor muscle bends a joint during contraction; [1 mark]
The extensor muscle straightens a joint during contraction; [1 mark]
Muscle that is contracting is the agonist; [1 mark]
Muscle that is relaxing or lengthening is the antagonist;

84
Q

when a myofibril contracts which band decreases in length and which stay the same

A

decrease - H and I band
stay same - A band

85
Q

compare para and sympa

A
  • both neurones connect to SAN
  • both parts of involuntary nervous system
  • sympa speed up heart, para slowd down
    sympa prepares body for action, para prepares body for recovery
86
Q

explain the effect of exercise on changes in oxygen consumption

A
  • increases oxygen consumption
  • as there is increased respiration
  • more atp needed by muscles
  • oxygen required to convert lactic acid to glucose
87
Q

Explain why muscles occur in antagonistic pairs

A

can only work in one direction
therefore a need to create opposite forces

biology (10 decks)

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