Karteikarten
Exercise 2
Karten in diesem Stapel (56)
- 1What is the main limiting factor for exercise intensity?Restriction of oxygen supply to skeletal muscle
- 2Why is carbon dioxide not a significant limiting factor for exercise?Easily removed by rapid diffusion across membranes
- 3Which system causes changes in the cardiorespiratory system in anticipation of exercise?CNS
- 4Which system causes changes in the cardiorespiratory system during the first respiratory cycle of exercise?Sensory group III/IV afferents in muscles and joints
- 5What causes increased ventilation during exercise over a period of minutes?Changes in metabolites such as H+ and ADP detected by chemoreceptors
- 6What are the 2 ways that blood supply to muscle can be increased during exercise?Increase in cardiac output
Redistribution of blood to skeletal muscle - 7What is the effect of H+ from anaerobic respiration on the bronchi?Bronchodilation
- 8What is the effect of H+ from anaerobic respiration on the respiratory muscles?Increased depth of respiration
- 9How does the relative proportion of inspiration and expiration change during exercise?2/3 respiratory cycle inspiration during exercise
Only 1/3 at rest - 10What is the benefit of changing the pattern of inspiration and expiration with exercise?Better diffusion between alveoli and blood
- 11What is the frequency of respiration linked to?Gait cycle
- 12What is meant by the symbol Q?Flow
- 13What variable must change in order to maintain the arterial PaO2 in the blood with increased cardiac output?Increase oxygen uptake
- 14Which part of the lung is better ventilated?Lower region
- 15Which part of the lung is better perfused?Lower region
- 16What happens to ventilation and perfusion of the lung during exercise?More of lung perfused and ventilated effectively
- 17Which enzyme aids the 'offloading' of carbon dioxide at the lungs?Carbonic anhydrase
- 18What happens to capillary transit time during exercise?Increased force of heart muscle contraction
Increased blood velocity
Reduced capillary transit time - 19What is the effect of capillary transit time on the capillary PO2?Saturation of the capillary PO2 occurs at a longer distance along the capillary during exercise, due to reduced capillary transit time
Saturation may not occur during maximal exercise - 20Why is more oxygen required to diffuse from the lungs to reach saturation during exercise?Initial venous PO2 is reduced
- 21Why can oxygen uptake into the blood sometimes decrease during maximal exercise?Velocity of blood can exceed capacity for diffusion
- 22Why does ventilation become less efficient during exerciseMore work required by respiratory muscles, hence more oxygen is diverted to these
- 23What happens to the cardiac output to respiratory muscles during exercise?Increased
- 24Will the increased work done by respiratory muscles ever exceed the additional oxygen taken up?Not in healthy individuals
However, can occur in asthma or brachycephalic dogs - 25What happens to veins at the onset of exercise?Venoconstriction
- 26Why does venous return increase during exercise?More vigorous inhalation makes the intrathoracic pressure more negative
- 27What receptors cause vasodilation of blood vessels in skeletal muscle during exercise?Chemoreceptors that detect metabolites
- 28Why does vasoconstriction occur in tissues other than skeletal muscle during exercise?Maintenance of total peripheral resistance
- 29Which reflex minimises the vasodilation in blood vessels to skeletal muscle during exercise?Baroreceptor reflex
- 30What is the function of this reflex?Maintenance of blood pressure
- 31Give 2 reasons why blood haematocrit may increase during exercisePlasma loss (sweating and dehydration)
Splenic contraction to release red blood cells in dogs and horses - 32Why can an increased haematocrit during exercise be disadvantageous?Increased viscosity of blood
Increased work on heart due to increased resistance to flow - 33What can be an advantage of increased haematocrit during exercise, aside from additional oxygen transport?Increased cardiac output increases turbulent flow
However, increased viscosity can help minimise this - 34Which molecule in muscle has a higher affinity for oxygen than haemoglobin?Myoglobin
- 35At which pO2 will this molecule dissociate from oxygen and why?3 mm Hg
Correct pO2 for mitochondria - 36What is the effect of increased CO2, H+ and temperature on the haemoglobin dissociation curve?Curve shifted to right
- 37What is the consequence of the haemoglobin dissociation curve shifting to the left?Increased affinity for oxygen
Loads oxygen more easily in the lungs
Dissociates less readily in skeletal muscle - 38What is the consequence of the haemoglobin dissociation curve shifting to the right?Reduced affinity for oxygen
Increased dissociation of oxygen in skeletal muscle - 39What causes the haemoglobin dissociation curve to shift to the left?Increased ventilation:
Reduced CO2
Reduced H+
Reduced temperature - 40What is the effect of metabolites on capillary beds?Dilate arteriole = increased flow and pressure downstream
Opening of capillaries in capillary beds - 41Why is opening of capillary beds important during exercise?Increases blood flow without reducing transit time significantly
- 42What is the effect of opening capillary beds on diffusion of oxygen from the blood?Increased surface area of capillaries for diffusion
- 43What is the effect of isometric contraction on blood flow to skeletal muscle?Compresses blood flow completely, causing local tissue hypoxia and nociceptor activation
- 44What is meant by 'preload' on the heart?Venous return
- 45What does the width of a pressure-volume loop represent?Stroke volume
- 46What is the effect of reduced stroke volume on the pressure-volume loop?Increased end systolic volume
- 47What is the effect of the Frank-Starling mechanism on the pressure-volume loop?Restores stroke volume
Increased end diastolic volume - 48What is ionotropism?Increase in force of contraction
- 49What is chronotropism?Increase in rate of contraction
- 50What is dromotropism?Increased rate of conduction of electrical potentials
- 51Is increased stroke volume or increased heart rate more significant during exercise in the domestic species?Increased heart rate
- 52Which 2 variables cause blood pressure to increase during exercise?Cardiac output increases
Total peripheral resistance only decreases - 53Give the equation to calculate blood pressureBP = CO x TPR
- 54Which 2 variables affect the amount by which blood pressure will increase during exercise, in any given animal?Degree of exercise
Constriction of blood vessels to skeletal muscle - 55What is pulse pressure?Difference between systolic and diastolic pressure
- 56Why are horses prone to epistaxis (nosebleeds) following vigorous exercise?Large species so higher pulmonary blood pressure
This increases more than systemic blood pressure with exercise
Possible rupture of pulmonary capillary beds
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- BVSc Animal Health Science 2 (Exercise & Temperature Regulation) Karteikarten am Exercise 2, erstellt von Florence Edwards am 01/03/2017.
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- Florence Edwards
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