Describe the role of golgi tendons and muscle spindles in PNF. [4]
muscle spindles
- Detect increase in muscle length/how far and fast muscle is being stretched
- message sent to nervous system
- initiates stretch reflex/muscle contraction
- prevents over stretching
Golgi tendons
- detect an increase in muscle tension
- inhibitory signals/autogenic inhibition
- overrides stretch reflex/muscle relaxes
Explain how and why the components of cardiac output differ in trained and untrained performers [3]
- trained athlete would have lower HR (60bpm)
- trained athlete had higher resting stroke volume
- regular training leads to cardiac hypertrophy
- trained performer has more forceful contraction
Explain the role of adrenaline on heart prior to race [4]
anticipatory rise prior to the race
maintains heart rate during the race
adrenaline at the SA node
more firing at the sinoatrial node
What is the significance of an increase in arterio-venous difference for a game’s player [5]
- difference in oxygen content in the arterial and venous blood
- more oxygen is needed by the muscles
- as oxygen needed for ATP production
- increased endurance/aerobic exercise
- improved performance
- increased oxygen diffusion at lungs/alveoli/muscles
- so there is more oxygen in blood
- and more CO2 is produced
Explain the term cardio vascular drift [4]
- increase in HR/increase in ejection fraction/ decrease in SV
- fluid is lost as sweat
- reduced plasma/ increased blood viscosity
- reduced venous return
- Starling’s law
- Q increases as more energy needed to cool body
Identify two functions of the fast component of Excess exercise Post Oxygen Consumption [2]
restores phosphocreatine stores
resaturate myoglobin with oxygen
Describe the Bohr shift [3]
- occurs as a result of an increase in CO2/blood acidity/decreased PH/ increased temperature
- increase in hydrogen ions
- oxyhaemoglobin curve shifts to the right
- haemoglobin has lower affinity for oxygen at muscles/higher affinity at the lungs
Describe the role of haemoglobin [3]
- transports oxygen in the blood/oxygen to the muscles
- less saturation of oxygen with haemoglobin during exercise
- an increase of oxygen release at the muscles/ oxyhaemoglobin dissociation at the working muscles
- muscles receive more oxygen during exercise
Describe the role of myoglobin during exercise [2]
stores/transports in the muscle
- myoglobin has a higher affinity for oxygen
- oxygen dissociates from myoglobin at lower PO2
Describe how the body redistributes blood to the skeletal muscles during exercise [4]
- chemo/proprio/baroreceptors detect changes in blood acidity/pressure/ movement due to exercise
- vasomotor control centre controls blood flow
- increased sympathetic impulses at non essential muscles/sphincters contract/close/ vasoconstriction
- decreased sympathetic nerve impulses at the essential muscles/ sphincters relax/open/ vasodilation
Define the tern expiratory reserve volume [1]
volume of air that can forcibly be expired after a normal breath
Define the term tidal volume [1]
volume of air breathed in or out per breath
Define the term minute ventilation [1]
volume of air breathed in or out per minute
Describe how oxygen and carbon move between the blood and the muscles [4]
-diffusion is the movement of gasses down a concentration gradient
- partial pressure of oxygen is higher in the blood and lower in the muscles
- diffuses to the muscles
- partial pressure of carbon dioxide is higher in the muscles
- diffuses into the blood
Explain how increases in level of carbon dioxide and acidity in the blood cause breathing rate to increase [4]
- changes detected by chemoreceptors in artic arch/ carotid arteries/medulla
- nerve impulses to the respiratory Centre/medulla
- nervous output to breathing muscles via phrenic/sympathetic nerve
- increased rate of contraction of the diaphragm and intercostal muscles
