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103 Cards in this Set
- Front
- Back
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Cardiac Cycle
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Events that occur between two consecutive heartbeats (systole to systole)
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Describe diastole. How much of the cycle does it take?
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Relaxation phase during which the chambers fill with blood (T wave to QRS)—62% of cycle duration
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Describe Systole. How much of the cycle does it take?
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Contraction phase during which the chambers expel blood (QRS to T wave)—38% of cycle duration
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EDV
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End Diastolic Volume. The amount of blood left in ventricle before contraction
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ESV
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End Systolic Volume. The amount of blood left in centricle after contraction
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Cardiac Output
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Total volume of blood pumped by the ventricle per minute
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Formula for Cardiac Output
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Q = HR x SV
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Ejection Fraction
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Proportion of blood pumped out of the left ventricle each beat
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What is the average ejection fraction at rest?
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60%
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How do we measure indirect calirometry
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By measuring the volume and rate of oxygen used (VO2) as well as the CO2 produced (VCO2), energy expenditure can be determined.
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Caloric Equivalent
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The number of kilocalories produced per liter of oxygen consumed
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Caloric Cost
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Energy expenditure of an activity performed for a specific period of time
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I Kcal = How many kJ
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4.184
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RER
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The ratio of the volume of carbon dioxide produced divided by the volume of oxygen consumed on a total body level
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What can RER determine
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Caloric expenditure as well as the proportion of energy from fat and carbohydrates
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As exercise increases what will happen to the source of fuel?
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As the intensity of the exercise increases the reliance upon carbohydrate stores for energy increases, whereas reliance on fat stores decreases
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MET
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A unit that represents the metabolic equivalent in multiples of resting rate oxygen consumption of any given activity
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What is the standard value at resting MET
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3.5 ml/kg/min
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Whats the difference between fat mass and adipose tissue?
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Fat is a chemical mixture of lipids
Adipose tissue is composed of fat, but also other chemicals and tissues |
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What is fat-free mass?
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Anything but fat!!
Water Bone mineral Non-bone mineral Protein Residual |
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The Body Mass Index (BMI)
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BMI = body mass (kg) / stature (m2)
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Advantages of BMI
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Measures are simple and convenient to take
High correlation with fat mass Suitable for large scale surveys |
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Disadvantages of BMI
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Does not distinguish between fat mass and fat free mass ie. also highly correlated with fat free mass!
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Density formula
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D = M/V
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An object immersed in water is supported by a force equivalent to
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the mass of water it displaces
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When you raising a skin fold what are you actually raising?
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Adipose Tissue.
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What elite activity would favour having body fat
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Cold Water swimming where you need body fat for heat and also bouyancy
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Why would we be interested in bone mineral density?
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Osteoporosis in older adults
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Systole & % of cycle
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Contraction phase during which the chambers expel blood. QRS to T wave.
38% |
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Diastole & % of cycle
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Relaxation phase during which the chamber fill with blood. T wave to QRS
62% of cycle duration |
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Stroke Volume
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Volume of blood pumped per contraction
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How much % blood do we typically eject each beat?
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Typically we eject 60% of blood with each beat
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Cardiac Output
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Total volume of blood pumped by the ventricle per minute
Q = HR x SV |
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End Systolic Volume
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Volume of blood left in ventricle after contraction
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End Diastolic Volume
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Volume of blood left before contraction.
After refilling Larger than systolic |
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What is the limiting factor for aerobic performance?
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Cardiac output
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What is the Cardiac cycle?
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The events that occur between two consecutive heartbeats (systole to systole)
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Stroke Volume & Formula
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The volume of blood which is ejected per contraction
SV = EDV - ESV |
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Ejection fraction
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Proportion of blood pumped out of the left ventricle each beat.
Percentage of the end diastolic volume which is ejected with each beat. |
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Structure of arteries
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Elastic, stretchy (eases systole BP)
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Arterioles
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More muscular vessels. Distributes blood around body strategically.
Distributes blood according to need |
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Capillaries
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Exchange vessels.
No elastic or connective tissue. Single layer of cells with perforations. Adapted for exchange purposes |
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Venules and Veins
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Return of blood to the heart.
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How does the blood get back to the heart?
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Muscular pump
Respiratory pump Venous tone |
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Why is HR response lower in swimming compared with running?
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Because of the horizontal position = larger venous return = larger refill = increase SV
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Autoregulation of Blood Distribution
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Arterioles within organs and blood tissue dilate or constrict in response to local chemical environment
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Extrinsic neural control of blood distribution
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Sympathetic nerves within walls of blood vessels are stimulated causing vessels to constrict
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Most of blood at rest is located within?
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Veins
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Why doesn’t HR increase as a chronic response to training?
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Because if there was an increase in HR there would be no time to refill the chambers. Therefore minimal Q (Cardiac Output)
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Describe how SV changes to increasing exercise intensities
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Increases with increasing rates of work up to intensities of 40-60% of max or higher.
May continue to increase up through maximal exercise intensity, generally in highly trained athletes Magnitude of changes in SV depends on position of body during exercise. |
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Frank Starling mechanism
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More blood in the ventricle causes it to stretch more and contract with more force
Increased ventricular contractility Decreased total peripheral resistance due to increased vasodilation of blood vessels to active muscles. |
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Resting Cardiac Output value?
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Approx 5.0L/min
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Approx Max cardiac output value?
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40 L/min
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At higher exercise intensities does Cardiac output increase in response to HR or SV?
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Further increases in Q are more a result of increases in HR than SV since SV tends to plateau at higher work rates.
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Describe cardiovascular drift
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Gradual decrease in stroke volume and systemic pulmonary arterial pressures and in an increase in HR.
Occurs with steady-state prolonged exercise or exercise in a hot environment |
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Can we produce energy?
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No, can’t produce it. Energy is transferred, stored or released.
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Catabolism
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Process of breaking down food sources
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ATP
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High energy compound stored in our cells and is the source of all energy used at rest or during exercise
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During moderate to severe muscular effort, the body relies mostly on which source for fuel?
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Carbohydrates
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In what situation will protein used for fuel?
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Only in extreme circumstances
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Glucose
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Soluble, Simple Sugar
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When does fat provide the source for energy needs?
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At rest and during prolonged, low intensity activity
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Why is fat less accessible for metabolism than CHO?
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Because it must be reduced to glycerol and free fatty acids. Only FFA is used to form ATP
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Why is fat limited as an energy source?
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Because of the rate it releases energy. It is very reluctant to release energy.
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Why are fat stores essential?
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They are also a reserve for fat soluble vitamins.
Vitamin D |
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ATP-PCr System, rate of release and capacity, location
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Anaerobic process
High fast Cytoplasm |
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Glycolytic system rate of release and capacity, location
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Rapid energy release
Requires 12 enzymatic reactions to breakdown glucose. Cytoplasm |
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Oxidative system rate of release and capacity, location
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High capacity
Low power Sub maximal Mitochondria Relies on oxygen |
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Describe nervous system response effects
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Localised, rapid and short-lived
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Describe hormonal system response effects
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Slower in response, longer-lasting and more general.
Circulate in the blood, not sent directly |
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The main function of aldosterone and ADH is to?
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Minimise urine/water loss
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Aldosterone
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Released by the adrenal cortex in response to decreased blood pressure; promotes sodium reabsorption in kidneys and increases plasma volume.
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ADH
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Released by the posterior pituitary gland in response to increased blood osmolarity; promotes water conservation by increasing plasma volume.
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Why is EPO important?
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It is a hormone which regulates red blood cell production by stimulating bone marrow cells. It is important in our adaptation to training and to altitude due to the oxygen carrying capacity of RBC
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Growth hormone is produced where?
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Anterior pituitary gland
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Role of Growth Hormone as an erogenic aid
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Promotes muscle growth and hypertrophy by facilitating amino acid transport.
Also increases lipolysis |
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Glycolysis is ? Anaerobic or Aerobic?
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Breakdown of glucose; can be either
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Glycogenesis
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Process by which glycogen is broken into glucose-1phosphate to be used by muscles
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Gluconeogenesis
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Process by which glucose is synthesised from other molecules such as amino acids
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Name the two catecholamines and their roles
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Epinephrine and norepinephrine
Stimulated by the sympathetic nervous system to prepare for immediate action. Increase rate and force of heart contraction, blood pressure and respiration Increase metabolic rate, glycogenolysis, and release of glucose and FFA into blood Allow more blood to go to the skeletal muscles through vasodilation and vasoconstriction of specific vessels |
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Where are catecholamines released from?
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Adrenal Medulla
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Two hormones of the pancreas
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Insulin and Glucagon
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Insulin is released when?
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Secreted when plasma glucose levels are high
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Glucagon is secreted when?
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Plasma glucose concentrations are below normal and stored glycogen must be broken down
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Which 3 hormones increase glucose metabolism
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Glucagon
Epinephrine Norepinephrine |
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When hormone promotes gluconeogenesis and amino acid release
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Cortisol
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What four hormones increase the metabolism of fat?
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Cortisol
Epinephrine Norepinephrine Growth hormone |
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Genesis
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Formation, breakdown
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Lysis
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Breakdown
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Caloric equivalent
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The number of kilocalories produced per litre of oxygen consumed.
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Caloric cost
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Energy expenditure of an activity performed for a specific period of time
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1 Kilocalorie = How many kJ
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4.184kJ
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RER
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RER Respiratory Exchange Rate = the ratio of the volume of carbon dioxide produced divide by the volume of oxygen consumed on a total body level
RER = VCo2/Vo2 |
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What does RER determine
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RER determines the caloric expenditure as well as the proportion of energy from fat and carbohydrates.
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How do you determine the caloric cost (kcal/min)
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O2 consumed (L/min) x caloric equivalent (kcal/Lo2)
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If the RER is close to 1 which fuel is likely to be used?
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CHO
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Why does RER never get down to 0.7?
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We never consume 100% fat. It is why we starve to death yet can still have skin folds.
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Why can the RER go past 1 in some exercise intensities?
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At higher exercise intensities you start to hyperventilate which further propels CO2 from blood. Driving the RER past 1
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MET
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Metabolic equivalent
A unit that represents the metabolic equivalent in multiples of resting rate, Oxygen consumption of any given activity. |
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What % of the population is overweight or obese?
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60%
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Watts
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Kp x 9.81 x 6 x RPM/60
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To get RV from VC what do you times VC by for males and females?
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Males .24
Females = .28 |
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Sources of error associated with hydro densitometry
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Biological assumptions (FM & FFM)
Prediction equations Measurement of water temp and underwater mass |
