Exercise Physiology L6

• Lactate threshold


  The exercise intensity at which blood lactate reaches a critical level.
• PNF stretching


  Proprioceptive neuromuscular facilitation
• CRAC


  Contract-Relax-Antagonist-Contract
• Partial pressure of oxygen


  How much oxygen there is in the air.
• Myoglobin


  Oxygen-carrying molecule found in muscle cells.
• Cardiovascular drift


  An increase in heart rate when exercising at a constant work rate over a prolonged period or in a hot climate. (compensates for a decrease in stroke volume to maintain a constant cardiac output).
• Veins


  Blood vessels that carry blood back to the heart.
• Arteries

  Blood vessels that carry blood away from the heart.
• Capillaries


  Microscopic blood vessel where gaseous exchange take place.
• Vascular shunting


  Process that increases blood flow to active areas during exercise by diverting blood away from inactive areas; achieved by vasodilation and vasoconstriction.
• Vasoconstriction


  Narrowing of blood vessels.
• Vasodilation


  Widening of blood vessels.
• Cardiac cycle (in order)


  Atrial Diastole

  Ventricular Diastole

  Atrial Systole

  Ventricular Systole
• Diastole


  When the heart relaxes and fills with blood.
• Systole


  Contraction of the heart to force blood out.
• Erythrocytes


  red blood cells
• Leucocytes


  White blood cells
• Thrombocytes


  Platelets
• 4 venous return mechanisms


  Skeletal muscle pump

  Pocket valves

  Respiratory pump

  Cardiac suction
• Cardiac output


  Heart rate x stroke volume

  Q= SV x HR
• Stroke Volume (SV)


  The volume of blood pumped out of the left ventricle with each contraction.
• Heart Rate (HR)


  Number of heart beats per minute
• Starling's Law


  The more the heart is filled during diastole the more forcefully it contracts.
• Ejection fraction


  Percentage of blood pumped out of the left ventricle with each contraction (at rest it's 55%, during exercise it's 70%+).
• Device used to measure blood pressure


  Sphygmomanometer.
• Muscles used in respiration at rest


  Intercostal muscles & diaphragm.
• Concentration gradient


  Difference in the concentration of a substance from one location to another.
• Pulmonary diffusion (external respiration)


  Exchange of gas molecules (oxygen and carbon dioxide) at the alveoli.
• Internal respiration


  Exchange of gases at muscles sites.
• Spirometry


  Used to measure lung volume.
• Tidal volume (Vt)


  Amount of air that moves in and out of the lungs during a normal breath.
• Inspiratory Reserve Volume (IRV)


  Amount of air that can be forcefully inhaled after a normal breath in.
• Expiratory Reserve Volume (ERV)

  Amount of air that can be forcefully exhaled after a normal breath out.
• Residual Volume (RV)


  Amount of air remaining in the lungs after a forced exhalation.
• Total lung capacity


  The total volume of air the lungs can hold (Vt + RV + IRV + ERV)
• Vital Capacity (VC)


  Maximum volume of air you can breathe in and out: TV + IRV + ERV
• Minute Ventilation (VE)


  The amount of air breathed per minute (Vt x BR) (5-8 L/min at rest)
• Haemoglobin


  The protein that carries oxygen in the red blood cells.
• Motor unit


  A motor neuron and all of the muscle fibres it innervates.
• Sympathetic nervous system


  The part of the autonomic nervous system (ANS) that stimulates the heart to beat faster.