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