Applied anatomy and physiology

• Impact of physical activity:

  • reduce the potential incidence of heart disease

  •prevent or reduce high blood pressure - high blood pressure can be a health risk as there is a higher force exerted against the blood vessel wall

  reduce the adverse effects of high cholesterol levels — high levels of 'bad' cholesterol can increase the risk of heart disease reduce the likelihood/incidence of a stroke
• Anticipatory rise:

  • Increase in heart rate just before activity due to release of adrenaline
• Redistribution of blood:

  • Vascular shunt mechanism causes vasoconstriction (narrowing of blood vessels) and vasodilation (opening of blood vessels) to regulate blood flow
• Cardiac conduction:

  • Electrical impulse passing through the heart leading to contraction
  • Specialised cardiac muscle cells in heart walls send signals causing contraction
• Carbon dioxide:

  • Exhaled as part of the breathing process
• Sympathetic system:

  • Part of autonomic nervous system that speeds up heart rate
• Parasympathetic system:

  • Part of autonomic nervous system that decreases heart rate
• • Chemoreceptor- detect change in carbon dioxide levels
  • proprioceptors- detects change in muscles movement
  • baroreceptors- responds to change in blood pressure to either increase or decrease heart rate
• • Venous return: the return of blood to the right side of the heart via the vena cava.
  • starlings law: the more blood that is pumped into the heart, the more blood must be pumped out of it, resulting in stroke volume increasing
  • bohr shift- A shift to the right of the oxyhaemoglobin dissociation curve I.e the period when muscles require more oxygen, so the dissociation of oxygen from haemoglobin occurs more readily
• Oxygen debt: The amount of extra oxygen required by the body following exercise.
• Anaerobic threshold: The point at which lactic acid begins to accumulate in the bloodstream during high intensity exercise.
• Heart rate (HR): The number of times the heart contracts per minute.
• • Tidal volume- volume of air breathed in or out per breath
  • Inspiratory reserve volume (IRV)- volume of air that can be forcibly inspired after a normal breath
  • Expiratory reserve volume (ERV)- volume of air that can be forcibly expired after a normal breath
  • Residual volume- volume of air that remains in the lungs after maximum expiration
• • Slow twitch fibres: useful for long distance endurance events e.g marathon
  • Fast oxidative glycolytic type (IIa)- useful for activities of medium to high intensity, more resistant to fatigue e.g 800 metre run
  • Fast glycolytic (IIb)- useful for explosive, fast events e.g sprinting, javelin
• • Muscle spindles- They detect how far and how fast a muscle is being stretched. During PNF stretching, the spindles detect the stretch and trigger a stretch reflex, preventing overstretching.
  • Golgi tendon organs- and they detect the level of tension in a muscle. and send signals to the medulla, which allows the antagonist muscle to lengthen and relax
• • motor unit: this consists of a motor neurone and its muscle fibres.Only one type of muscle fibre can be found in a particular motor unit, so each muscle is made up of many motor units which vary in size
  • spatial summation: this is when the strength of a contraction changes by rotating the frequency of the impulse to motor units to delay fatigue
  • wave summation: this when the nerve impulse is repeated with no time to relax, resulting in a smooth, sustained contraction
  • tetanic contraction: this is a forceful, sustained, smooth muscle contraction caused by a series of fast repeating stimuli
• • the all or none law': once a motor neurone stimulates the muscle fibres, either all of them contract or none of them do. This is because it is impossible for a motor unit to only partially contract
• Sagittal plane/transverse axis

  • movement at the shoulder and hip (Ball and socket joint)
  • consist of flexion, extension and hyperextension
  • movement of elbow and knee (Flexion And extension)
  • movement at ankle (plantar flexion and dorsiflexion
• Frontal plane/sagittal axis

  • movement occurs at shoulder and hip
  • Adduction and abduction
• Transverse/longitudinal axis

  • movement consist of horizontal abduction and adduction
• Types of muscle contractions:

  • isotonic: when a muscle contracts to create movement
  • concentric: when a muscle shortens under tension
  • eccentric: when a muscle lengthens under tension
  • isometric: when a muscle is under tension but there is no visible movement
• The anaerobic ATP-PC energy system:

  • used for short maximal movement
  • doesn’t have oxygen
  • It can last up to 10 seconds

  Equation for this system:

  • Phosphocreatine (PC)—> Phosphate (Pi) + creatine (C) + energy

  The energy is then used to resynthesis ATP
• Short duration/high intensity exercise:

  • Uses ATP-PC and Anaerobic glycolytic system

  In short term lactate anaerobic system:

  • energy has to be produced rapidly and this results in lactate accumulation in the muscles
  • this slows down enzyme activity, which in turn affects the breakdown of glycogen, causing muscle fatigue
  • the exercise intensity increases, the body moves from working aerobically to anaerobically as the lactate threshold is reached
  • lactate levels will continue to increase as the OBLA point is reached
• • Lactate threshold: The point during exercise at which lactic acid quickly accumulates in the blood
  • OBLA: (onset blood lactate accumulation) The point at which blood lactate levels go above 4 millimoles per litre
• Factors affecting VO2 max:

  Physiological:

  • increased maximum cardiac output
  • increased lactate threshold

  Training:

  • VO2 max can be improved by up to 10-20% following aerobic training (fartlek, continuous).

  Lifestyle:

  • Smoking, poor fitness and diet reduce VO2 max values

  Gender:

  • Men generally have 20% higher VO2 max than women

  Age:

  • As we get older, our VO2 max declines as our body systems become less efficient
• Measurements of energy expenditure:

  • indirect calorimetry: measures how much carbon dioxide is produced and how much oxygen is consumed during the gaseous exchange process at rest and during aerobic exercise.
  • Lactate sampling: small blood sample is taken from a performer to check blood lactate levels, used as a means of measuring exercise intensity.
  • VO2 max test: 'bleep test' (progressive shuttle run) and accurate tests that can be performed in sports laboratories
  • Respiratory exchange ratio (RER): this is the ratio of carbon dioxide produced compared to oxygen consumed
• Altitude training:

  • carried out at 2000m or more above sea level as the partial pressure of oxygen is lower here
  • body adapts by creating more red blood cells to carry oxygen.
  • additional oxygen-carrying blood cell is an advantage for endurance athletes/performers returning to sea level to compete.This is not a permanent change and is only a short-term advantage.
• High intensity interval training (HIIT):

  • periods of short, high intensity exercise with less intense recovery periods.

  Four main variables include:

  • the duration of the work phase
  • the intensity or speed of the work phase
  • the duration of the recovery phase
  • the number of work phases and recovery phases
• Plyometrics:

  • as bounding or depth jumping. It is designed to increase power by using an eccentric contraction followed by a larger concentric contraction.

  Speed, agility, quickness (SAQ):

  • training combines speed, agility and quickness. There are many variations and forms of this training and it is relatively easy to plan an SAQ session to make it sport-specific.
• The effects of sport And physical activity on the CV system:

  • increased stroke volume
  • increased cardiac output
  • cardiac hypertrophy
  • bradycardia (low resting heart rate)
• Cardiac conduction system:

  1. From the SAN the electrical impulse spreads to the walls of the atria
  2. The atria contracts which forces blood into the ventricles
  3. The impulse passes through the AVN found in the atrioventricular septum
  4. The AVN delays transition of the cardiac impulse for 0.1 seconds to enable the atria to fully contract
  5. The electrical impulse passes down the specialised fibres to the bundle of his
  6. The bundle of his branches out into smaller bundles called purkinji fibres
  7. The purkinji fibres spread throughout the ventricles causing them to contract
• Cardiovascular drift:

  • occurs after 10 minutes of exercise
  • blood loses plasma—-> blood becomes viscous
  • which means it’s harder to pump around the body
  • resulting in reduce stroke volume and increased heart rate.
  • happens in a warm environment at Steady-state exercise
• Arteries:

  • carry blood at high pressure
  • thick elastic walls
  • small lumen

  Capillaries:

  • 1 cell thick
  • adapted for diffusion/gaseous exchange

  Veins:

  • large lumen
  • contains valves
  • carries blood at low pressure
  • thin walls
• ATP-PC system:

  Advantages:

  • ATP re-synthesises rapidly using the ATP-PC system
  • No fatiguing by products

  Disadvantages:

  • Limited supply of phosphocreatine in the muscles
  • Only one molecule of ATP can re-synthesised for every mole of Pc
  • Re-synthesis can only take place in the presence of oxygen
• Anaerobic glycolytic system:

  • system last 2-3 minutes but peaks at 45 seconds
  • Re-synthesises ATP from the breakdown of glucose by anaerobic glycolysis
  • Kicks in when the PC system have depleted
  • Glycogen phosphorylase is activated to break down the glycogen into pyruvic acid
  • 2 molecules of ATP produced form 1 molecule of glucose
• Anaerobic glycolytic system:

  Advantages:

  • Last longer then ATP-PC
  • can be used for sprint finish
  • When oxygen is present lactic acid can be converted back into liver glycogen or used as fuel oxidation into CO2 and water

  Disadvantage:

  • Lactic acid is a by product
  • Decrease in Ph levels can denature enzymes
  • Only small amounts of energy is released from glycogen under anaerobic conditions
• Aerobic system: produces 36-38 ATP

  1. Glycolysis

  • converts glucose into pyruvate to produce energy
  • Forms 2 ATP molecules

  1. The kreb cycle

  • Hydrogen is removed form citric acid and then the rearranged form of citric acid undergoes oxidative carboxylation
  • Carbon and hydrogen are given off

  1. The electron transport chain

  • Hydrogen ions are oxidised to form water whole hydrogen electrons provide energy to re-synthesise ATP
• Aerobic system:

  Advantages:

  • More ATP produced
  • There are no fatiguing by products
  • Lots of glycogen stores so exercise can last for a longer time

  Disadvantage:

  • Complicated system- can’t be used straight away. Takes a while for the oxygen to be available
  • Fatty acid transportation to the muscle is low and requires 15% more oxygen to be broken down than glycogen