Exercise physiology exam notes Flashcards
Lung anatomy?
Structurally:
Upper respiratory tract
Lower respiratory tract
Functionally:
Conduction Zone
Respiratory Zone
Whats in the upper respiratory tract?
Nose Nasal cavity Mouth Pharynx Larynx
What’s the Laryngeal prominence?
Adams apple
Not sex specific
Larger in males due to hormonal effects
What’s in the lower respiratory tract?
Trachea Lungs Bronchi Bronchioles (conducting, terminal, respiratory) Alveolar ducts Alveolar sacs Alveolus
What’s in the alveoli?
Type 1 cell: More numerous, enable gas exchange
Type 11 cell: Produce surfactant prevents lungs collapsing
Whats are the respiratory control centres in the brain?
Pons:
Apneustic area
Pneumotaxic area
Medulla Rhythmicity area:
Ventral and Dorsal group
Important nerves?
Phrenic Nerve (C3-C5 Root) Intercostal Nerve (T1-T11 Root) Vagus Nerve (X) Glossopharyngeal Nerve (IX)
receptors in our body?
Chemoreceptors
Mechanoreceptors
Stretch receptors
Irritant receptors - detects irritant gasses eg.
Peripheral proprioceptors - bring about change in muscles
Types of chemoreceptors?
Central
Peripheral:
Cartoid body
Aortic body
Muscles involved in breathing?
Accessory muscles
Diaphragm 75% (in the exam)
Intercostal muscles
Abdominal muscles
What is Boyle’s Law?
Pressure of a gas in a closed container inversely proportional to volume of container at a constant temperature
P1V1 = P2V2
Steps of Inhalation?
Diaphragm flattens
External intercostals Up and Out, causing elevation of ribs
Increase Volume
Decrease Pressure
Air rushes in
Steps at exhalation at rest?
Passive process
Elastic recoil
Decrease Volume
Increase pressure
Air forced out
Steps of exhalation during exercise?
Becomes an active process
Muscles used are the internal intercostals, external obliques, rectus abdomens, transverse abdominus
More features of the pons?
Apneustic area:
Prolonged and slow rate of breathing
Overridden by pneumotaxic
Features of the pneumotaxic area?
Inhibitory impulse, limits duration of breath in
Breathing becomes faster by limiting breathing in
More features of the medulla oblongata?
Rhythmicity area:
Controls basic rate of breathing
Dorsal respiratory group - mainly inspiratory , can also talk to the ventral, but ventral can’t talk back
Ventral respiratory group
How do the control centres of the brain talk to each other?(pneumotaxic area, apneustic area, Dorsal respiratory group, Ventral respiratory group, and central chemoreceptors)
Pneumotaxic controls inspiration to expiration (inhibition of inspiration), can talk to the DRG and VRG for this
Apneustic area causes inspiration, can talk to the DRG and the VRG for this
DRG can impact upon the VRG or down to the nerves responsible for breathing inspiration
VRG can tell nerves for inspiration and expiration nerves for breathing
DRG can also get information from central chemoreceptors
In blood in brain during strenuous exercise Oxygen goes down, CO2 and H+ go up
H+ can’t cross blood brain barrier, so chemoreceptors respond to CO2 which can cross
CO2 reacts with water to form H2CO3 which then forms HCO3(-) + H+
DRG also gets input from cranial nerves 9 and 10
Features of the peripheral chemoreceptors?
Due to Glomus cells, which have K+ going in and out of them
If oxygen is down 60mmHg, the potassium channels close, so potassium builds up in the cell, calcium channels open due to increased voltage so calcium rushes in
Exocytosis of vesicles from cell which are filled with dopamine, which increases breathing rate
What do central and peripheral chemoreceptors react to more?
Central - Co2
Peripheral - Oxygen
Make notes on all lung capacity terminology from previous flashcards
ok, it’s on ELE as well
What is the FVC manoeuvre?
Breath in and out and then a massive breath out until run out of breath
FVC is the amount of air produced
FEV1 is the amount of air exhaled at 1 second (roughly 80%)
Peak expiratory flow rate
What are flow volume loops?
THERE ARE 4 TYPES OF FLOW VOLUME LOOPS (in the exam)
On a graph have a positive flow (going out) and negative flow (going in)
Breath in and out, then a fast breath in, then breath out as fast as you can, then fast breath in
On graph looks like a triangle with a semi circle on the bottom
Volume on x axis (goes the opposite way), flow on y axis,
How do flow volume loops change if there is an obstruction by a pathological condition?
Triangle on top will slope down rather than straight down
How do flow volume loops change if they are restricted and total lung volume is too low?
The same just far smaller
Flow volume loop with exercise induced asthma?
The same but keep on getting smaller during exercise
Equation for minute ventilation?
Breathing rate x tidal volume
What is alveolar ventilation?
Portion of minute ventilation mixes with air in alveoli
150ml-200ml healthy males
If physiologic dead space isn’t above 60% you are fine
It’s worked out find minute ventilation using Breathing rate x tidal volume
Then use Minute ventilation - dead space = alveolar ventilation
What’s the ventilatory threshold?
The point at which pulmonary ventilation increases disproportionately with oxygen consumption during graded exercise
How to investigate respiratory muscle fatigue?
Investigated by having one ballon just above diaphragm and one just bellow
Stimulate phrenic nerve to cause them to hiccup
Can then look at the pressure difference
what is respiratory muscle metaboreflex?
With increases in different muscle metabolites
Changes occur not in our control
Will go in more depth next week
Structure of cardiovascular system?
Pump
High pressure circuit - arteries
Exchange vessels
Low pressure circuit - veins
Function of cardiovascular system?
Delivery of oxygen and nutrients
Removal of CO2 and other waste products
Support thermoregulation and control body fluid balance
Hormone transport
Regulation of immune function
Cardiovascular system parts and function?
Heart - creates pressure
Arteries and arterioles - carry blood away from heart
Capillaries - exchange
Veins and venules carry blood towards the heart
Copy and paste heart anatomy from last year
Vena cava Right atrium Tricuspid valve Right ventricle Pulmonary semilunar valve Pulmonary artery Lungs Pulmonary veins Left atrium Bicuspid valve Left ventricle Aortic valve Aorta
Cardiac conduction sequence?
Sinoatrial node
Current makes right atrium contract
Current goes to Bachmann’s bundle makes left atrium contract
Through septum of heart
Goes to atrioventricular node
His bundle
Purkinje fibers
Left posterior bundle and right bundle, ventricles contract
ECG wave?
P wave small hump - atrial depolarisation
QRS complex - down, large up, down, normal = ventricular depolarisation
T wave - small hump - ventricular repolarisation
QRS hides P wave repolarisation§
Bradycardic means?
Less than 60 bpm
Tachycardia means?
More than 100 bpm
What is Henry’s law?
When a mixture of gas is in contact with a liquid each gas dissolves in the liquid in proportion to it’s partial pressure and solubility until equilibrium is achieved and the gas partial pressure are equal in both locations
Solubility is constant
Pressure gradient is critical - gas diffuse from high pressure areas to low pressure areas
2 ways we can transfer oxygen in blood?
Dissolved in plasma-
3ml per L of blood
70kg male has 5L of blood so 15ml of oxygen
Bound to haemoglobin
Hb4 + 4O2 = Hb4O8
Men 150g/L (5 to 10% decrease for women)
Each gram of Hb carries 1.34ml of oxygen
How is carbon dioxide transferred in the blood?
Dissolved = 7%
Carbamino compounds (-23%), as carbaminohaemoglobin
Biocarbonate ions (70%) In plasma as HCO3-
Equation for CO2 + H2O to HCO3- and it relating to chloride shift?
CO2 + H2O = (via carbonic anhydrase) H2CO3 = H(+) + HCO3-
HCO3- leaves the red blood cell, Cl- moves in to restore charge
What is blood pressure?
Pressure exerted by blood on vessel walls
Systolic BP = ventricular systole
Diastolic BP = Ventricular diastole
What is heart rate variability?
Variation in time interval between heartbeats aka beat to beat interval
Less variable is bad because shows heart can’t react to scenarios, relates to lots of negative outcomes of well being eg. depression ibs
Examples of autonomic control?
Sympathetic:
Increase heart rate and inotropism
Parasympathetic:
Decrease heart rate and inotropism
What is inotropism?
Strength of heart beat
What is VO2?
The difference between volume of gas inhaled and volume of gas exhaled per unit of time
VO2 = {(VI x Fio2) - (Ve x Feo2)} / T
VI = volume inspired
Fio2 = fraction of inspired oxygen
VE = Volume expired
Fe02 = Fraction of expired oxygen
What determines someones VO2?
Blood flow and oxygen extraction
What is the FICK EQUATION?
Underpins VO2
= Q x (CaO2 - CVO2)
Q = cardiac output
Oxygen arterial venus différence is the bit in brackets just represents how much oxygen at the beginning of the blood vessel then how much is at the end
Definitions for maximal oxygen uptake?
Maximum rate at which an individual can take up and utilise oxygen while breathing at sea level
What is lactate threshold?
The first increase above baseline
What is lactate turn point?
When there is a sudden increase in Lactate
If 2 people have the same VO2 max but one has a higher lactate threshold who will perform better?
Person with higher lactate threshold
Does blood pressure increase with %VO2 max?
Yes
Why is there increased extraction of O2 from the blood during exercise?
Sigmoid curve
Acidity, Pco2, 2,3-BPG, and temperature help remove oxygen
Acidosis increases during exercise, pH decreases, affinity of Hb decreases, more O2 delivered to acidic sites
Pco2 rises, affinity of Hb decrease, more oxygen delivered
BPG formed during glycolysis helps to unload by binding with Hb
Temperature increases affinity of Hb decreases, more O2 is delivered to warmed up muscle
What increases oxygen utilisation?
Increased extraction of O2 from the blood
Dilation of peripheral vascular beds
Increased Q
Increase in pulmonary blood flow
Increase in ventilation
What was done in the Wilkerson et al 2012 paper?
Known that Dietary nitrate supplementation has been reported to improve short distance time trial (TT) perfor- mance by 1–3 % in club-level cyclists.
It is not known if these ergogenic effects persist in longer endurance events or if dietary nitrate supplementation can enhance perfor- mance to the same extent in better trained individuals.
Eight well-trained male cyclists performed two laboratory- based 50 mile TTs: (1) 2.5 h after consuming 0.5 L of nitrate-rich beetroot juice (BR) and (2) 2.5 h after con- suming 0.5 L of nitrate-depleted BR as a placebo (PL).
BR elevated plasma and reduced completion time by 0.8% which wasn’t statistically significant
There was a significant correlation between the increased post-beverage plasma [NO2-] with BR and the reduction in TT completion time
Power output (PO) was not different between the condi- tions at any point
but oxygen uptake (V_ O2) tended to be lower in BR resulting in a significantly larger PO/VO2 ratio
In conclusion, acute dietary supplementation with beetroot juice did not sig- nificantly improve 50 mile TT performance in well-trained cyclists. It is possible that the better training status of the cyclists in this study might reduce the physiological and performance response to NO3- supplementation compared
Question is later one
What is the weakness in the Wilkerson et al introduction?
They are trying to answer does Nitrate supplementation work in longer races as well as does it work in better trained athletes
Makes it difficult to decipher differences, is it the distance or the training status of individuals that is responsible from any differences in previous work
Problems with the methods?
In pre lab they only did a 10 mile TT for familiarisation which isn’t the same as the 50 Mile tested, but they were familiar with longer indoor sessions so this is somewhat irrelevant
What design did the study employ for experimental testing?
Randomised, single blind, crossover design
Comments about the result section of the study?
Had subheadings
Logical order
Tables and figures clear and appropriate
Seeds are sown for discussion of the relationship between plasma nitrite increase and TT performance
Features of the discussion about the study?
Increase of 0.8% is valid in a competition
Useful they identify responders and non responders to the beetroot juice
Subjects were not different in Vo2 than previous study but did maintain it for 50 miles
What further studies could be done to the Wilkerson et al one?
Further supplementation eg during
Only answer one of the questions at a time
Use an optimal nitrate loading regimen
Why is it important to know the variability in TT performance for a study of this nature?
If the effect of the intervention is within the variability it could be just down to chance
What could improve the Wilkerson et al study?
At least one proper familiarisation trial conductied
More subjects to investigate the responder vs non responder idea
Ecological validity would be improved by completing the TT on the road, even though this is conflicted by weather
2 areas of the brain that are visible in the top view of the cerebral cortex?
Motor and sensory
Anatomy of a neuron?
Dendrites (little trees) Soma - cell body Axon hillock - connects to the Axon Axon Axon terminal - synapses are here
Types of Axoplasmic transport?
They are moved along Microtubules (made of tubulin)
Anterograde transport the movement of molecules/organelles outward, from the cell body, due to Kinesin
Retrorade transport (toward the cell body) due to Dynein
Need to take notes from old deck on how an action potential is generated
Depolarisation occurs when sufficient stimulus depolarises the cell, voltage gated Na+ open and sodium floods in at-55mv
Repolarisation - returning to resting membrane potential, Na+ channels close, K+ leaves the cell due to voltage hated K+ channels
Hyperpolarisation - caused by delay in closing of voltage gated K+ channels
ACTION POTENTIAL PROPAGATION?
The action potential generated at the axon hillock propagates as a wave along the axon. The currents flowing inwards at a point on the axon during an action potential spread out along the axon, and depolarize the adjacent sections of its membrane.
2 types of synapses?
Electrical synapses
Chemical synapses
Describe electrical synapses?
Gap junctions which are bidirectional and involve ions and small molecules
Describe chemical synapses?
Involved In Neurons
Muscle fibres
CNS - Axondendritic, axiomatic and axoaxonic
Proteins involved in exocytosis?
Snare proteins
▸ V-Snare:
▸ Synaptotagmin
▸ Synaptobrevin
▸ T-Snare:
▸ Snap-25
▸ Syntaxin
describe a muscle contraction?
Nerve impulse arrives at terminal of motor neuron, ACh leaves neuron via exocytosis
‣ ACh diffuses across synaptic cleft and triggers action potential.
‣ Muscle AP travels along transverse tubule opening Ca2+ release channels in SR, allowing calcium ions into sarcoplasm.
‣ Ca2+ binds to troponin, exposing binding sites for myosin.
‣ Myosin heads bind to actin and initiate power stroke.
‣ Ca2+ release channels in SR close and Ca2+ active transport pumps use ATP to restore low level of Ca2+ in sarcoplasm
types of neurotransmitters?
Amino acids
▸ Amines (derived from amino acids)
▸ Peptides (constructed from amino acids)
▸ Major exception is ACh
Neurotransmitter groups?
Cholinergic Neurons
▸ Catecholaminergic Neurons ▸ Serotonergic Neurons
▸ Amino Acidergic Neurons
What are Cholinergic neutrons?
Release Acetylcholine (ACh)
All motor neurons in spinal cord and the brain stem
Requires specific enzyme to synthesise called Choline Acetlytransferase
Done by combing Acetly-CoA and Choline
examples of catecholaminergic neurons?
Dopamine, norepinephrine, epinephrine
All made up of the protein Tyrosine
Example of Serotonergic neurons?
Serotonin (5-hydroxytryptamine (5- HT))
Made up of Tryptophan
Examples of AMINO ACIDERGIC NEURONS?
▸ Glutamate ▸ Glycine
▸ GABA (made up of Gammaminobutyric acid
How does cocaine work?
Dopamine is released by neurones and is normally re uptaken again by a transporter
But cocaine blocks this
Dopamine builds up and constantly stimulates the receptors
How does botox work?
Prevents neuron sending signals
So can be used to prevent specific muscles from contracting
What is a dynamometer?
Measures force, strength of a muscle contraction
In newtons or newton meters
Provides absolute and relative values
What is electromyography?
Recording changes in electrical potential of a muscle
Can be done on the surface or intramuscular
What is magnetic stimulation?
noninvasive form of brain stimulation in which a changing magnetic field is used to cause electric current at a specific area of the brain through electromagnetic induction.
What is the electrical stimulation value when used to stimulate a muscle?
130% of maximal twitch
What is a MOTOR EVOKED POTENTIAL?
The action potential stimulated by electrical or magnetic stimulation
What is a MWAVE?
earliest EMG response to the stimulation of a motor nerve
Measurements that can be done on electromyography?
Excitability: ▸ M-wave Amplitude ▸ M-wave Area Contractility: ▸ Twitch Force ▸ Time to peak twitch ▸ Half relaxation time ▸ Electromechanical delay
Voluntary Activation
Equation for BMI?
Weight(kg) / Height^2 (m)
Physical activity definition?
Any bodily movement produced by skeletal muscles that results in energy expenditure above the basal level
Physical activity guideline for toddlers?
3 hours daily
Physical activity guideline for children?
vigorous 60 mins a day
3x a week build muscle and bone strength
Physical activity guideline for adults?
2.5 hours a week
muscle work 2 times a week
What is used to measure bone density and it’s health?
DXA or QUS
Health of the bone is assed by biochemical markers, calciotrophic hormones and it’s rate of collagen synthesis
Difference between T score and Z score?
T looks at the small group
Z looks at the whole population
T scores used for bone density
(X - Xbar) / standard deviation
What is osteoporosis?
Systemic disease characterised by decreased bone mass, bone tissue deterioration and susceptibility to fracture
What percentage is bone mass related directly to genes?
70% so 30% we can change
Lifecycle on bone mass?
Before 20 more osteoblast activity (bone building) than osteoclast activity (bone break down)
After 50 reverses, big decrease in women due to menopause
What nutrition increases bone density?
calcium and vitamin D (90% from the sun)
Does vibration improve bone health?
Yes
Does vibration improve bone health?
Yes
What is altitude?
Metres above sea level
Provides exposure to a hypoxic environment due to a Decreased barometric pressure
Decreased ambient temperature
Increased solar radiation
What is hypoxia?
Inadequate supply of oxygen to respiring tissue
Why is there less oxygen available when we are at high altitude?
Higher you go less mass pushing down on us, so lower the pressure
Chemical makeup of air does not change
Because the pressure is lower, due to daltons law partial pressures of each chemical drop including oxygen as the overall atmospheric pressure is lower
Barometric pressure at sea level?
760mmHg
Does the percentage of oxygen change with altitude?
NO
Revise how partial pressures work
ok
What is normoxia?
Normal oxygen pressure
What is hyperoxia?
High oxygen pressure
What does hypobaric mean?
Low pressure
What is the oxygen cascade?
The fall in PO2 reduces the driving pressures for gas exchange in the lungs and in turn produces a cascade effects to the level of the mitochondria the final destination of the oxygen
So if inspired oxygen concentration decreased or barometric pressure decreased then inspired gas oxygen levels decreased
Therefore reduced alveolar ventilation and reduced oxygen consumption so reduced alveolar gas pressure,
Therefore Less blood flow and decrease in oxygen carrying haemoglobin so less oxygen in the cell
Oxygen carrying capacity of blood calculation? (Will be in the exam)
What’s the amount of O2 carried in the blood bound to haemoglobin at in males and females? Oxyhaemoglboin saturation = 82%
Males = 150g haemoglobin per litre of blood
Females = 130g per litre of blood
1g Hb can transport 1.34 ml O2
If given a height it doesn’t matter
Do the g of Hb per litre of blood x the amount ml of O2 1 g of Hb transports
Then multiply by the oxyhaemoglobin saturation
eg.
(150 x 1.34) x 0.82 = 164.82 per litre of blood for males
Why are performances better at short distances at moderate altitude to sea level?
Less friction for the runner
How much does Vo2 decrease every 100m above 1500m?
1%
Why is there a decline in maximal oxygen uptake as altitude increases above 1500m?
Decrease in pressure of oxygen (PaO2) in the alveolar
Breathing rate is going to increase due to chemoreceptors being activated
More breathing means an increased amount of CO2 removal
Too much CO2 breathed out so you experience hypocapnia
Which is then counteracted by the decreased volume of expired gas
pH becomes more alkali - resulting in more bicarbonate excretion, resulting in a fluid shift, decreases our stroke volume, so heart rate goes up, and therefore so does cardiac output
Vasoconstriction occurs, blood pressure increases - increases heart rate
Increase in heart rate is bad because it uses more energy, we want a balance between stroke volume and heart rate
Haemoglobin affinity decreases, easier to unload
What is mild altitude sickness?
Basically the same as a hangover
Causes from ascending too fast 500m/d
Or exercise vigorously
Describe high altitude pulmonary oedema?
develops 2-3 days when higher than 2500m
Can be fatal within hours
Accumulation of fluid in the lungs that prevents air spaces from opening up and filling with fresh air with each breath
bad coughing symptoms
Describe high altitude cerebral oedema?
An increase in blood flow to the brain is a normal response to low oxygen levels, as needs to maintain the oxygen to the brain. However, if the blood vessels in the brain are damage fluid may leak out and result in HACE
Symptoms severe headache, vomiting, coma
Immediate response to increased altitude?
Hyperventillation
Increase in blood flow
Resting system blood pressure increases
Increase in sub maximal blood flow compensates for arterial
EPO concentrations rapidly, then goes back to normal
Longer term response to increased altitude?
Increased blood O2 carrying capacity:
Initial decrease in plasma volume
So increase in RBC concentration and Hb synthesis
As old people are less active than younger what should be empathised in their training?
Stretching
Muscle activation
Core stability
Balance
= prehabilitation
Does shortening velocity of muscle decrease with age?
No
What happens to muscle as you get older?
muscle fibre loss of motor units begins at around 50-60
Muscle size begins to decrease at 30
What can decrease the loss of muscle mass through ageing?
Resistance training - increase muscle hypertrophy
What happens to neural function from ageing?
40% decline in spinal cord axons
10% decline in nerve conduction velocity, due to structural changes in myelinated neurones, resulting in increased internal distances, decreasing signal jumping over Schwann cells
Also a loss of fastest conducting axons and decrease in soma size
How does diabetes affect nerve conduction velocity?
Reduced Na+-K+-ATPase activity ‣ Increased Na+, K+, Sortibol, Fructose ‣ Increased Osmosis ‣ Accumulated water compresses nerves ‣ Decreased Nerve conduction velocity
Exercise reverses this process
How much does aerobic power decrease per year?
1% per year
2% if sedentary
Why does sprint length reduce in older people?
Reduced stride length
Increase in contact time of foot with ground
Why does heart rate decrease with age?
Lack of electrical conductivity in the heart
In an older person is there less blood in the brain (cerebral blood flow)?
Yes
Does physical activity help to prevent cognitive decline?
Yes
Exam structure
24 multiple choice - not neg
5 calculations
11 short answer questions
content:
respiratory physiology (1 SAQ on flow volume loops)
Cardiovascular physiology
Neural physiology
Physical activity, bones and body composition
Altitude and exercise
Ageing and exercise
Labs and seminars:
Lactate threshold and economy
Wingate anaerobic test
ECG
Ventilatory threshold - including maximal oxygen uptake (will be a question worth 7 marks on it)
Wilkerson et al 2012 (1 Sam worth 5 marks)
First part of Wilkerson et al will be - summarise Wilkerson et al’s paper, then something else
What you have to write down for Calculations?
1 mark for formula
1 mark for unit
1 mark for answer
Calculations for cardiac output?
Total volume of blood pumped by the ventricle per minute
Q (L.min^-1) = HR x SV
SV(ml) = EDV - ESV
so Q (L.min^-1) = HR x (EDV - ESV)
Calculations for blood pressure?
Mean arterial blood pressure = 2/3 DBP + 1/3 SBP
units are mmHg
Calculations for Oxygen carrying capacity of blood?
Units are ml per litre of blood
{O2} = ({HB} x 1.34 x 0.97) + (PO2 x 0.003)
{HB} = males 150g/1L, females 130g/1L
PO2 = 100
- 34 represents ml O2 g Hb
- 97 represents 97% saturation
- 003 represents O2 solubility
If asked:
Total = both sides of the equation
Equation for find change of blood in arterial and Venus?
CaO2 - CvO2 = difference
Do arterial - however much oxygen is used
Units are ml of O2
Fick equation?
VO2 (ml/O2/min) = Q (l.min^-1) x (CaO2 - CvO2)
Equation for running economy?
If not given VO2
VO2 (ml/Kg/Min) = 13.5(Speed (m\s)) - 8.5
If given speed in km/hr, /60 then /60 then x 1000
But if given Vo2 in ml/kg/min
O2 cost (ml/kg/km) = VO2 (ml/kg/min) / Speed (Km/hr) /60)
This is on the exam
Resting membrane potential?
-70mmv
Generated by SOPI pumps
Describe action potential?
Depolarisation occurs
If hits -55mv, action potential generated, pushing us to + 30 mmv, as sodium channels open
Repolarisation, sodium channels close, potassium channels open goes down,
takes too long causing hyper-polarisation
What’s action potential propagation?
Action potential travels as each section affects the area next to it
think of salty banana
Extra thing to note when drawing flow volume loops?
Note the residual volume
What is Ficks law of diffusion?
The rate of gas transfer is proportional to the tissue area, the diffusion coefficient to the gas, and the difference in partial pressure of the gas on the 2 sides of the tissue, and is inversely proportional to the thickness
What is the respiratory muscle metaboreflex?
Fatiguing contractions of the diaphragm expiratory and and accessory respiratory muscles
Increase in reflex activating metabolites
Increase in group III/IV phrenic afferent (up to the brain) discharge
Brain says:
Increase effector perceptions, sympathetic efferent discharge, limb vasoconstriction and locomotor muscle fatigue
And decrease O2 transport
What is running economy?
The Vo2 required to run at sub-maximal speeds
What’s the lactate threshold?
The running speed at which the first increase in blood {Lactate} above baseline values occurs
What’s the lactate turning point?
Is the running speed at which there is a sudden and sustained breakpoint in blood {lactate}
Just before graph ramps up
What is a wind gate test?
Measures high-intensity, anaerobic of energy generation
What occurs at the extremes of exercise intensity?
ATP is broken down quickly to release energy required to sustain muscular contraction
The rate of consumptions exceeds production aerobically in the mitochondria via oxidative phosphorylation
A matter of second ATP is regenerated via phosphocreatine system providing a lot of energy
Power output drops very quickly
Don’t become immediately exhausted due to substrate level phosphorylation and the anaerobic portion of glycolysis
Why is the measurement of the electrical activity of the heart possible?
Body fluids contain electrolytes which are good electrical conductors
Electrical impulses generated in the heart are conducted through body fluids to the skin
Describe blood pressure?
The pressure exerted bu the blood on the vessel walls
The term usually refers to arterial blood press
Systolic blood pressure and diastolic blood pressure are the factors we measure
Mean arterial pressure = 2/3 DBP + 1/3 SBP
Typical ECG response to exercise?
Minor changes in P wave form
Superimposistion of P and T waves of successive beats (starts to look like an “M”
Slight decrease in R wave amplitude
Q wave may be deeper
Increase in T wave amplitude
Minimal shortening of QRS complex
Depression of J point (the J point is found where the S wave makes its sharp deviation (right hand turn) toward the T wave
At rest the J point should come back to the isoelectric line
Rate related shortening of QT interval
Will be in exam
What is a GXT? (graded exercise test)
Incremental exercise test to volitional exhaustion
The test may be performed on any ergometer; cycle, treadmill, rower, kayak etc.
begins at an easy intensity, and becomes progressively harder until maximal exertion
Increases may be step-wise, usually around 3 minute stages, so physiological parameters such as heart rate and oxygen consumption reach steady state for each level of intensity.
The test may also follow a ramp protocol, in which the intensity steadily progresses to max
The test completes when the athlete cannot maintain the work output.
What happens during a GXT?
As the intensity increases, the rate of ATP consumed by muscular contraction exceeds the rate it can be replenished by aerobic respiration
The deficit is met by substrate level phosphorylation, during anaerobic glycolysis
Lactate is produced and protons (H+) accumulate in the blood, lowering pH.
Acidity is regulated by bicarbonate buffering – HCO3- ions released from the red blood cell cytosol into the plasma reacts with the H+ ions forming H2O and CO2 to maintain a stable blood pH
The excess carbon dioxide augments an increase in ventilation.
The oxygen consumption continues to increase in a linear
fashion to the increase in intensity until V! max
What happens if you plot Co2 production and O2 consumption during a GXT?
lot best fit lines through two clear gradients. The first line will have a gradient slightly less than 1, while the second slightly greater. The intercept of the two lines is a ‘threshold’ point which represents the effect of increased acidosis.
Activity levels below and above this threshold are often categorised as light to moderate and severe respectively.
Since the deflection point in CO2 production reflects the acidosis associated with lactate production, it serves as an indirect method for measuring the lactate threshold.
Like the lactate threshold, the ventilatory threshold may be used to determine relative intensity
If an individual exercises at 80% of their VT, or gas exchange threshold, their exercise intensity is ?
moderate
Likewise, at 30% of the difference between VT and maximal intensity (during a ramp test), the intensity will be heavy.
This is sometimes called 30 Delta, for those researchers who classify intensity using the Delta concept.
Describe maximal oxygen uptake?
The maximum ability to take in, transport, and utilise oxygen during exercise
he gold standard aerobic fitness test, used extensively in the assessment of athletes and research.
The criteria used to ensure the test is a true reflection of maximum effort include: Achievement of ‘plateau’ of oxygen consumption (e.g. < 150
ml.min-1 increase in V! for a > 25 W increment in power output); RER > 1.10; Heart rate ± 10 beats above O2
predicted maximum; RPE > 17 (Borg 6-20 scale). Two of these criteria is sufficient to accept the test results, and can be reinforced by subjective assessment of the athlete.
What is tidal volume?
Amount per breath
Breathing frequency?
Number of breaths
How to work out alveolar ventilation?
0.7 x tidal volume
How to work out dead space ventilation?
0.3 x tidal volume
What is inspiratory reserve volume?
Maximum volume of air that can be inhaled (from top of tidal volume on graph)
What is Expiratory reserve capacity?
Maximum volume of air that can be voluntarily exhaled (from bottom of tidal volume on graph)
What is residual volume?
Volume of air remaining in the lungs after maximal exhalation
What is vital capacity?
Maximum volume that can be inhaled and exhaled (IRV + Tidal volume + ERV)
What is FRC functional residual capacity?
Volume of air present in the lungs at the end of passive expiration (ERV + RV)
