Section 8: Applied Anatomy and Physiology Flashcards
What is phosphocreatine (PC)?
PC is an energy-rich phosphate compound found in the sarcoplasm of the muscles
What is ATP?
Adenosine triphosphate (ATP) is the only useable form of energy in the body
How can PC stores be replenished?
PC stores can only be replenished during low-intensity work when oxygen is available. It takes 30 seconds for 50% PC replenishment and 3 minutes for 100%
What is the duration that PC stores last?
PC stores last 5-8 seconds
What are the 3 energy systems?
3 types of energy system:
- the aerobic system
- the anaerobic glycolytic system
- ATP-PC system
What is the ratio for PC molecules to ATP molecules produced?
1:1
What is the enzyme used to break down ATP?
ATPase used to break ATP into ADP
What does creatine kinase do?
creatine kinase detects high levels of ADP and breaks down PC in the muscles to phosphate and creatine, releasing energy
How is ATP re-synthesised in the ATP-PC system?
the energy released when PC is broken down is used to convert ADP to ATP
What are the advantages of the ATP-PC system?
- ATP can be re-synthesised quickly
- PC stores re-synthesised quickly
- no fatiguing by-products
- creatine supplements can be used to extend the time the system is used
What are the disadvantages of the ATP-PC system?
- limited supply of PC in the muscles, only up to 8 seconds
- one mole of ATP can be re-synthesised for one mole of PC
- can only re-synthesise ATP in the presence of oxygen
How does the anaerobic glycolytic system work?
- when PC stores are depleted, glycogen phosphorylase breaks down glycogen into glucose
- glucose converted into pyruvic acid by phosphofructokinase (PFK)
- pyruvic acid further converted to lactic acid by lactate dehydrogenase as it is an anaerobic process
What are the two anaerobic energy systems?
ATP-PC
anaerobic glycolytic system
What are the advantages of the anaerobic glycolytic system?
- ATP can be re-synthesised quite quickly due to few reactions
- lasts longer than the ATP-PC system
- lactic acid can be converted back into liver glycogen or used as a fuel through oxidation into CO2 and H2O in the presence of oxygen
- can be used for a sprint finish
What are the disadvantages of the anaerobic glycolytic system?
- lactic acid as product, which can denature enzymes
- only a small amount of energy can be released from glycogen under anaerobic conditions, 5% as opposed to 95% in aerobic conditions
How much energy is produced from the anaerobic glycolytic system?
net total of 2 ATP molecules produced from 1 molecule of glucose broken down (actually 4 but 2 used in glycolysis)
What are the 3 stages of the aerobic system?
- Glycolysis
- Krebs cycle
- Electron transport chain
What happens in the first stage (glycolysis) of the aerobic system?
- anaerobic and takes place in the sarcoplasm
- glycogen broken down into glucose by glycogen phosphorylase
- further broken down to pyruvic acid
- 2 net molecules of ATP produced
- pyruvic acid oxidised into 2 acetyl groups and carried into the Krebs cycle by coenzyme A
What happens in the second stage (Krebs cycle) of the aerobic system?
- 2 acetyl groups diffuse into the matrix of the mitochondria
- they combine with oxaloacetic acid to form citric acid
- hydrogen is removed from citric acid and it undergoes oxidative carboxylation
- carbon and hydrogen given off
- carbon forms CO2 and is breathed out
- hydrogen taken into the electron transport chain
What happens in the third stage (electron transport chain) of the aerobic system?
- hydrogen taken into the ETC by hydrogen carriers
- occurs in the cristae of the mitochondria where hydrogen splits into ions and electrons
- H+ ions oxidised to form water
- hydrogen electrons provide energy to re-synthesise ATP
- 34 molecules of ATP are formed
What fuel can be used for the aerobic system?
carbohydrates, glycogen
proteins, amino acids
fats, fatty acids
How is fat broken down in the aerobic system?
beta oxidation
- stored fat broken into glycerol and fatty acids
- fatty acids undergo beta oxidation where they are converted into acetyl coenzyme A
- follow same path as glycogen metabolism
Why is fat metabolism good for endurance events?
more ATP can be made from one molecule of fatty acids than one molecule of glucose
What are the advantages of the aerobic system?
- lots of ATP can be produced, 34 molecules
- no fatiguing by-products
- lots of glycogen and triglyceride stores so exercise can last a long time
What are the disadvantages of the aerobic system?
- complex system so requires time for enough oxygen to be available to meet the energy demands and ensure glucose and fatty acids are fully broken down
- fatty acid transportation to muscles is low and requires 15% more oxygen to be broken down than glycogen
What are the 4 ways of measuring energy expenditure?
lactate sampling
indirect calorimetry
VO2 max test
respiratory exchange ratio, RER
How is lactate sampling carried out?
a small blood sample taken and a handheld device analyses the blood and indicates how much lactate is present
State the function of indirect calorimetry
measures how much CO2 is produced and how much O2 is consumed at rest and during exercise, calculated gas volumes tell the main substrate (carbs or fats) that are used
What is a direct gas analysis?
- VO2 max test
- measures the concentration of oxygen that is inspired and the concentration of carbon dioxide that is expired
Describe the process of direct gas analysis for a performer on a treadmill
- runs on a treadmill until complete exhaustion
- the air expired is calculated by computer software (performer wears a mask)
- volume and conc of oxygen expired is compared to percentage of oxygen in atmospheric air to see how much oxygen has been used
What is the RER?
the ratio of carbon dioxide produced compared to oxygen consumed
State the equation for the respiratory exchange ratio
RER= carbon dioxide expired per minute/oxygen consumed per minute
What do RER values tell you?
- what fuel is being used
- approx 0.7=performer using fats
- close to 1=performer using carbohydrates
- over 1=anaerobic respiration
How do you measure RER?
- when the athlete is attached to a gas analyser while on a treadmill or cycle ergometer
- accurate readings of carbon dioxide produced and oxygen consumed are taken
What are the 4 specialist training methods?
- altitude training
- speed, agility and quickness (SAQ)
- plyometrics
- high intensity interval training (HIIT)
What are the 3 phases in the stretch shortening cycle (plyometrics)?
- pre-stretching/eccentric phase, on landing the performers performer an eccentric contraction
- amortisation, time between the eccentric and concentric contraction and must be as short as possible to not lose energy stored from eccentric contraction (lots lost as heat)
- concentric/ muscular contraction, uses the stored energy to increase the force of contraction
Define oxygen consumption or VO2
the amount of oxygen used to produce ATP
Define VO2 max
the maximum volume of oxygen that can be taken up by the muscles per minute
Define sub-maximal oxygen deficit
when there is not enough is not enough oxygen available at the start of exercise to provide all the energy (ATP) aerobically
What is EPOC?
excess-post exercise oxygen consumption EPOC, the amount of oxygen consumed during recovery above that which would have been consumed at rest during the same time
What are the 2 components of EPOC?
-fast and slow component
What is the fast component of EPOC?
the restoration of ATP and phosphocreatine stores and the re-saturation of myoglobin with oxygen
How long does complete restoration of phosphocreatine take?
takes up to 3 minutes but 50% of stores can be replenished after 30 seconds
What are the functions of the slow component in EPOC?
- removal of lactic acid
- maintenance of breathing and heart rates
- glycogen replenishment
- increase in body temperature
How can lactic acid be removed during the slow component of EPOC?
- when oxygen is present, lactic acid can be converted back into pyruvate and oxidised into CO2 and H2O
- transported in the blood to the liver where it’s converted to blood glucose and glycogen (Cori cycle)
- converted into protein
- removed in sweat and urine
Define the Cori cycle
the process where lactic acid is transported in the blood to the liver where it is converted to blood glucose and glycogen
Why is a cool-down essential for lactic acid removal?
- most of the lactic acid can be oxidised in mitochondria
- so cooling-down keeps the metabolic rate of the muscles high and keeps capillaries dilated so O2 can be flushed through, removing lactic acid
When does the slow replenishment stage of recovery begin?
as soon as lactic acid appears in the muscle cell and continues using breathed oxygen until recovery is complete
What factors affect the rate of lactate accumulation?
- exercise intensity
- muscle fibre type
- rate of blood lactate removal
- respiratory exchange ratio
- fitness of the performer
Define OBLA
the point when lactate levels go above 4 millimoles per litre
Define lactate threshold
the point during exercise at which lactic acid quickly accumulates in the blood
How is lactate threshold expressed?
as a percentage of VO2 max
How is lactate formed?
via the dissociation of lactic acid. lactic acid release H+ and the remaining compound forms with Na+ or K+ to form lactate
Define VO2 max
the maximum volume of oxygen that can be taken up by the muscles per minute
Define oxygen consumption
the amount of oxygen used to produce ATP
When we start to exercise, why is insufficient oxygen distributed to the tissues for all energy to be provided aerobically?
- it takes time for our circulatory system to respond to the increased demand for oxygen
- takes time for the mitochondria to adjust to the rate of aerobic respiration needed
Define sub-maximal oxygen deficit
when there is not enough oxygen available at the start of exercise to provide all the energy (ATP) aerobically
What are the physiological factors that increase VO2 max?
- increased max cardiac output
- increased stroke volume/ejection fraction/cardiac hypertrophy
- greater heart rate range
- less oxygen being used for the heart muscle so more available to muscles
- increased levels of haemoglobin and red blood cell count
- increased stores of glycogen and triglycerides
- increased myoglobin content
- increased capillarisation around the muscles
- increased number and size of mitochondria
- increased surface area of alveoli
- increased lactate tolerance
What lifestyle choices can reduce VO2 max?
- smoking
- sedentary lifestyle
- poor diet
- poor fitness
How does body composition alter VO2 max?
a higher percentage of body fat decreases VO2 max
What is the affect of gender on VO2 max?
men typically have approx 20% higher Vo2 max than women
What is the affect of age on VO2 max?
as age increases VO2 max declines because our body systems become less efficient
State the factors affecting VO2 max
- physiological
- lifestyle
- age
- gender
- genetics
- body composition
- training
How can training improve VO2 max?
-can be improved by up to 10-20% following a period of aerobic training (continuous, fartlek, aerobic intervals)
Define altitude training
usually done at 2500m+ above sea level where the partial pressure of oxygen is lower
State the benefits of altitude training
- increases oxygen carrying capacity of blood
- increase in EPO
- increase in capillarisation
- increase in red blood cell number
- increase in haemoglobin concentration
- increase in lactate tolerance
State the disadvantages of altitude training
- loss of fitness or detraining (due to reduction of partial pressure of oxygen)
- altitude sickness
- homesickness
- benefits gained lost very quickly when returning to sea level
- body can only produce a limited amount of EPO
State the advantages of HIIT for a games player
-works anaerobic/aerobic system required in games
-mixture of high and low intensity mimics the game
-work: rest ratio can be altered to meet specific demands of sport/position
-can improve a range of components of fitness required in teams games e.g. aerobic endurance, anaerobic power, speed, muscular endurance
-develops performer’s ability to perform sports specific skills under fatigue/buffer effects if lactic acid
-
State the disadvantages/the ways HIIT training isn’t effective for a games performer
- not appropriate for all positions, other training methods may be more appropriate e.g. weight training for rugby player
- high intensity increases risk of injury
- intensity can negatively impact on skill performance
- work: rest intervals differ by sports/position
Define speed
how fast a person can move over a specified distance or how quickly a body part can be put into motion
Define agility
the ability to move and position the body quickly and effectively while under control
What components of fitness can be developed through SAQ training?
- speed
- agility
- flexibility
- balance
- co-ordination
