Physical Education

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  • Created by: Hbrandxx
  • Created on: 17-05-17 10:27

Skeletal system

Joints:

  • The ligament connects bone to bone and stabilises joint during movement.
  • Synovial joints allow free movement; synovial fluid reduces friction.
  • Types of synovial joints: hinge (knee), ball + socket (hip), condyloid (wrist), gliding (spine) and pivot (radio-ular).

Planes of movement:

  • SAGGITAL: lies vertically. Divides the body into left and right from the medial (midline) to the lateral (outside).
  •  FRONTAL: lies vertically. Divides the body into anterior (front) and posterior (back).
  • TRANSVERSE: lies horizontally. Divides the body into superior (upper) and inferior (lower).
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Skeletal system

Saggital:

  • Flexion decreases the joint angle, usually to the anterior of the body.
  • Extension increases the joint anlge, usually to the posterior of the body.
  • Dorsi-flesion decreases the joint angle bringing the toes up.
  • Plantar-flexion increases the joint angle moving the toes down.

Frontal:

  • Abduction moves the articulating bone away from the midline of the body.
  • Adduction moves the articulating bone closer to the midline of the body.

Transverse:

  • Horizontal extension moves the articulating bone away from the midline of the body.
  • Horizontal flexion moves the articulating bone closer to the midline of the body.
  • Rotation is a movement whereby articulating bones turn about their longitudinal axis in a screwdriver action.
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Skeletal system

Saggital:

  • Flexion decreases the joint angle, usually to the anterior of the body.
  • Extension increases the joint anlge, usually to the posterior of the body.
  • Dorsi-flesion decreases the joint angle bringing the toes up.
  • Plantar-flexion increases the joint angle moving the toes down.

Frontal:

  • Abduction moves the articulating bone away from the midline of the body.
  • Adduction moves the articulating bone closer to the midline of the body.

Transverse:

  • Horizontal extension moves the articulating bone away from the midline of the body.
  • Horizontal flexion moves the articulating bone closer to the midline of the body.
  • Rotation is a movement whereby articulating bones turn about their longitudinal axis in a screwdriver action.
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Muscular system

  • Origin: the point of muscular attachment to a stationary bone which stays relatively fixed during muscular contraction (biceps brachii’s origin is on the scapula during a bicep curl).
  • Insertion: the point of muscular attachment to a moveable bone which gets closer to the origin during muscular contraction (biceps brachii’s insertion is on the radius during a bicep curl).
  • Agonist: muscle reponsible for creating movement at a joint (prime mover).
  • Antagonist: muscle opposing the agonist, providing a resistance for co-ordinated movement.
  • Fixator: muscle that stabilises one part of the body whilst the other causes movement.

Muscle contraction:

  • Isotonic: muscle changes length concentrically or eccentrically.
  • Concentric: muscle shortens producing tension.
  • Eccentric: muscle lengthens producing tension.
  • Isometric is when a muscle contracts but doesn't change length.
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Skeletal muscle contraction

  • A skeletal muscle contracts when stimulated by an electrical impulse sent from the CNS.
  • Motor unit: a motor neuron and the muscle fibres stimulated by its axon.
  • Motor neuron: specialised cells which transmit nerve impulses to a group of muscle fibres.
  • Action potential: positive electrical charge inside the nerve and muscle cells which conducts the nerve impulse down the neuron and into the muscle fibre.
  • An action potential cannot cross the cleft without the neurotransmitter (Ach), secreted into cleft.
  • If enough is secreted, a muscle action potential is created; creates a wave of contraction down the muscle fibre (muscular contraction).
  • If the action potential doesn’t reach the threshold charge, none of the muscle fibres will contract: ALL-OR-NONE-LAW.
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Muscle fibers

Slow oxidative (type 1)

  • Store O2 in myoglobin and process O2 in the mitochondria; can work anaerobically.
  • Small force but can resist fatigue for a long duration (endurance events).
  • Provide energy for sub-maximal aerobic work.

Fast oxidative glycolytic (type 2)

  • Large force quickly, can resist fatigue (800m).

Fast glycolytic (type 2b)

  • Large stores of phosphocreatine for rapid energy production; can work anaerobically.
  • Largest force, fatigue quickly (powerlifter).
  • Recruited near muscle exhaustion.
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Muscle fibers

Muscle fibre type and motor units:

  • Small motor neurons stimulate few small muscle fibres. Creates a motor unit which produces a small and slow amount of force over a long period, resisting fatigue well.
  • Large motor neurons stimulate many large muscle fibres. Creates a motor unit which produces a large force rapidly, but fatigues quickly.

Muscle fibre type and recovery rates:

  • Type 1 provide energy for sub-maximal aerobic work; overall low force of contraction, each fibre recovers quickly.
  • Aerobic training work-to-relief ratios are very low (1:1).
  • Training can be performed daily; fibre damage not associated with aerobic activity.
  • Fast glycolytic fibres are recruited near muscle exhaustion, causes eccentric muscle fibre damage which causes DOMS felt 24-48 hours post-exercise (take longer to recover).
  • Therefore to maximise their use, maximal weight training work-to-relief ratios are very high (1:3)
  • Once they have been used to exhaustion, take 4-10 days to recover.
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Cardiovascular system

Structure of the heart:

  • Left side has a thicker muscular wall which can contract with more force to circulate oxygenated blood from the lungs through the large systemic circuit to muscles/organs.
  • Right side contracts to circulate deoxygenated blood from the body through the pulmonary circuit to the lungs.

Left side of the heart:

  • Blood oxygenated at the lungs and brought back to the left atria through the pulmonary vein.
  • Oxygenated blood moves from the left atria, through the bicuspid valve into the left ventricle.
  • Forced out the left side of the heart into the aorta; carries it to muscles and organs.

Right side of the heart:

  • Deoxygenated blood from muscles/organs arrives back at the right atria through vena cava.
  • Moves through tricuspid valve into right ventricle to be forced out the right side of the heart into the pulmonary artery; carries deoxygenated blood to the lungs.
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Cardiovascular system

The conduction system:

  • Cardiac muscle is myogenic; can generate an electrical impulse, which causes it to contract.
  • SA node generates the impulse and fires it through the right atrial walls, making them contract. Known as the 'pacemaker' as the firing rate determines heart rate.
  • AV node collects impulse and delays it to allow the atria to finish contracting, then releases the impulse to the Bundles of His.
  • Bundles of His (located in septum) splits the impulse into 2 to go through each ventricle.
  • Bundle branches carry the impulse to the base of each ventricle.
  • Purkinje fibres distribute the impulse through the ventricle walls making them contract.
  • Once the electrical impulses cycle is complete, atria + ventricles relax and heart re-fills w/blood (this process signifies one heartbeat).
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Cardiovascular system

The cardiac cycle:

  • Cardiac diastole; relaxation of the cardiac muscle, firstly of the atria then the ventricles.
  • Cardiac systole; contraction of the cardiac muscle, firstly at the aria then the ventricles.

Diastole:

  • As the atria + ventricles relax, they expand drawing blood into the atria.
  • Pressure in the atria increases opening AV valves.
  • Blood passively enters the ventricles.
  • SL valves are closed to prevent blood from leaving the heart.

Atrial systole:

  • The atria contract, forcing remaining blood intro the ventricles.
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Cardiovascular system

Ventricular systole:

  • Ventricles contract, increasing the pressure closing the AV valves to prevent backflow intro atria.
  • SL valves are forced open as blood is ejected from the ventricles into the aorta and pulmonary artery.

Conduction system control of the cardiac cycle:

  • The conduction system is the creation and passing of an electrical impulse through the cardiac muscle fibres which causes the cardiac cycle of events.
  • Together they form a single heartbeat, which occurs approx. 72 times per beat.

Heart rate:

  • N.o of beats completed in one minute.
  • Average resting HR is 72bmp; lower it is, the more efficient the cardiac muscle.
  • Bradycardia; HR lower than 60bpm, due to cardiac hypertrophy. HR max is 220-age.
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Cardiovascular system

Stroke volume:

  • Volume of blood ejected from the left ventricle per beat (SV).
  • Occurs during ventricular systole; as ventricle walls contract, blood ejected into the aorta.
  • Average resting is approx. 70ml.
  • Depends on venous return; the greater the return of blood the greater the volume available to the ventricles for ejecting.
  • Depends on ventricular elasticity and contractility; greater the stretch, greater the force of contraction.

Cardiac output (Q):

  • Volume of blood ejected from the left ventricle per minute (HR x SV = Q).
  • Based on resting values of 70bpm x 70ml = 5,000ml.
  • Due to cardiac hypertrophy, the cardiac muscle is more efficient as a greater volume of blood can be ejected per beat and heart rate can then reduce; athletes experience this.
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Cardiovascular system

Cardiac response to exercise and recovery:

  • Sub-maximal exercise is at a low-to-moderate intensity within your aerobic capacity or below the anaerobic threshold (aerobic work).
  • Maximal exercise is at a high intensity above a performer's aerobic capacity, takes you to exhaustion (anaerobic work/fatigue).

Heart rate response to exercise:

  • Increases in proportin with intensity until we reach our max.
  • During sustained sub-max exercise, our HR can plateau as we reach a steady state (plateau= supply meeting demand for O2 delivery and waste removal).
  • During max exercise, HR doesn't plateau as intensity continually increases (growing demand for O2 and waste removal which HR musn't try and meet).
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Cardiovascular system

Stroke volume reponse to exercise:

  • Increases in proportion to intensity until a plateau is reached at approx 40-60% of capacity.
  • Able to increase due to: increased venous return= greater volume of blood returning to the heart and filling the ventricles due to the muscle pump contracting.
  • Able to increase due to: Starling's Law= increased venous return leads to an increased stroke volume, due to an increased stretch of the ventricle walls and therefore force of contraction.
  • Reaches a plateau during sub-max intensity as increased HR towards max intensities doesn't allow enough time for ventricles to fill completely with blood in diastollic phase.

Cardiac output response to exercise:

  • Increases in proportion to intensity and plateau's during max exercise.
  • In recovery, there's a rapid decrease followed by a slower decrease to resting levels.
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Cardiovascular system

Heart rate regulation:

  • Although the heart is myogenic, brain is also involved with the ANS involuntarily regulating HR as it determines the firing rate of the SA node (higher the firing rate, higher the HR).
  • From the medulla oblongata, the CCC receives info from sensory nerves and sends direction through motor nerves to change HR.
  • Neural control:chemoreceptors in muscles, aorta inform the CCC of chemical changes in blood.
  • Neural control:proprioceptors in muscles/tendons/joints inform the CCC of motor activity.
  • Neural control:baroreceptors in blood vessel walls inform CCC of increased blood pressure.
  • Intrinsic control: temp changes affect viscosity of blood/speed of nerve impulse transmission.. venous return changes affect elasticity of ventricle walls, force of ventricular contraction and therefore stroke volume.
  • Hormonal control: adrenaline and noradrenaline released from adrenal glands increasing the force of ventricular contraction (and SV) and increasing speed of electrical activity through the heart (and HR).
  • If an increase in HR is required, sympathetic nervous system is initiated.
  • If a decrease in HR is required, parasympathetic nervous system is initiated.
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Cardiovascular system

The vascular system:

  • Dense network of blood vessels and blood; ensures O2 and nutrients are delivered to all respiring cells for energy production and waste removal.
  • Blood functions to: transport nutrients (O2, glucose), protect/fight disease, maintain homeostasis and regular temp.

Blood vessels:

  • Capillaries bring blood slowly into close contact w/muscle/organ cells for gaseous exchange.
  • Arterioles allow both vessels to vasodilate and vasoconstrict to regulate blood flow and control blood pressure.
  • Arteries have a large layer of smooth muscle and elastic tissue to cushion/smooth bloodflow.
  • Veins/venules transport de-oxygenated blood from muscles/organs back to the heart.
  • Main vein is the vena cava; one-way pocket valves to prevent backflow of blood as it travels against gravity.
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Cardiovascular system

Venous return mechanisms:

  • Pocket valves- one way valves in the veins which prevent the backflow of blood.
  • Smooth muscle- in the vein wall, venoconstricts to create venomotor tone to aid flow of blood.
  • Gravity- blood from upper body is helped to return by gravity.
  • Muscle pump- skeletal muscles contract compressing the veins between them, blood goes back to the heart.
  • Respiratory pump- during inspiration/expiration, pressure difference between the thoracic and abdominal cavity is created, blood goes back to heart.
  • Blood pooling is the accumulation of blood in the veins due to gravitational pull and lack of venous return.
  • Active recovery prevents this; low-intensity post exercise to maintain elevated heart and breathing rates.
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Cardiovascular system

Redistribution of cardiac output:

  • At rest, O2 is mostly used around our organs for digestion; as we exercise, demand from muscles for O2/nutrients increases and the more intense, the higher the demand.

Vascular shunt mechanism:

  • Redistribution of blood flow is controlled by vascular shunt mechanism.
  • Arterioles are blood vessels which carry oxygenated blood from the arteries to capillary beds, can vasodilate (maximises blood flow) and vasoconstrict (limits) to regulate blood flow.
  • At rest, higher % of cardiac output to organs whereas a low % for muscles.
  • This is due to: aterioles to organs vasodilate, increasing bloodflow whilst arterioles to muscles vasoconstrict to limit blood flow.
  • and due to: pre-capillary sphincters dilate, opening up the capillary beds to allow more blood to organ cells, while constricting, closing the capillary beds to muscle cells.
  • During exercise, roles reverse; arterioles and pre-capillary sphincters serve the capillary beds surrounding the muscles dilate which maximises blood flow while constricting the organs.
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Cardiovascular system

Vasomotor control:

  • Vascular shunt mechanism controlled by vasomotor control centre (VCC) in medulla oblongata.
  • Vasomotor tone- the partial state of smooth muscle constriction in the arterial walls.
  • VCC receives info from: chemoreceptors (CO2 rise/lactic acid during exercise), baroreceptors (pressure changes on arterial walls).
  • Sympathetic stimulation will then increase/decrease to alter level of vasoconstriction of arterioles and pre-capillary sphincters.
  • Sympathetic stimulation increases to vasoconstrict arterioles/pre-capillary sphincters to limit blood flow to an area like the muscles at rest.
  • Decreases to do the opposite (vasodilates to increase blood flow).
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Respiratory system

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Respiratory system

Functions:

  • Pulmonary ventilation (the inspiration and expiration of air).
  • Gaseous exchange: external respiration- O2 into blood and CO2 into lungs, internal respiration- O2 to respiring cells for energy and collection of waste products.

Structure:

  • Alveloi- tiny air sacs covered in capillaries which serve as the external site for gaseous exchange.
  • Gaseous exchange is the movement of O2 from alveoli in blood and CO2 from blood into alveoli.
  • Alveolar walls are perfect for gaseous exchange as they're once cell thick, moist and lined with fluid.
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Respiratory system

Functions:

  • Pulmonary ventilation (the inspiration and expiration of air).
  • Gaseous exchange: external respiration- O2 into blood and CO2 into lungs, internal respiration- O2 to respiring cells for energy and collection of waste products.

Structure:

  • Alveloi- tiny air sacs covered in capillaries which serve as the external site for gaseous exchange.
  • Gaseous exchange is the movement of O2 from alveoli in blood and CO2 from blood into alveoli.
  • Alveolar walls are perfect for gaseous exchange as they're once cell thick, moist and lined with fluid.
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Respiratory system

Gas transport:

  • O2 carried from alveoli to body tissues to produce anaerobic energy.
  • The greater the efficiency to inspire, transport + use O2, the greater the aerobic capacity to endure long periods of low-intensity exercise.
  • O2 can be transported as oxyhaemoglobin OR can be carried within blood plasma.
  • CO2 (waste product of aerobic energy, must be transported to alveoli to maintain effective performance).
  • CO2 can be transported by: carried as carbonic acid OR carbaminohaemoglobin OR dissolved in blood plasma.

Breathing rate:

  • N.o of inspirations or expirations taken in one minute (resting is 12-15 breaths per min)

Tidal volume:

  • Volume of air inspired/expired in a breath (average is 500ml).
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Respiratory system

Minute ventilation:

  • Volume of air inspired/expired per minute ( VE= TV x F) litres per minute.
  • Lower the more efficient gaseous exchange and transport is (can meet demands of O2 better at rest).

Respiratory volume response to exercise and recovery:

  • Demand for O2 to muscles increases, so supply of air to alveoli and oxygen to gaseous exchange is needed.

Breathing rate response to exercise:

  • Increases in proportion to exercise intensity until max is reached (50/60 breaths per min).
  • In steady state, can plateau as O2 supply meets demand from working muscles.
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Respiratory system

Tidal volume response to exercise:

  • Increases initially in proportion to intensity at sub-max exercise intensity.
  • Reaches a plateau during sub-max as increased breathing rate towards max intensities doesn't allow enough time and requires too much muscular effort for max inspirations/expirations.

Minute ventilation response to exercise:

  • Product of breathing rate + tidal volume; increases in line with intensity whereby BR and TV do.
  • During sustained steady state, can plateau as demand for O2 and waste removal is met.
  • During max intensity, VE doesn't plateau as intensity continues to increase; growing demand for O2 and waste removal which VE must try and meet.
  • TV will plateau and the further increase in VE is from a continued rise in breathing rate.
  • Use an active recovery to maintain VE and provide the continued need for O2 for aerobic energy production and removal of waste products.
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Respiratory system

Mechanics of breathing:

Inspiration:

  • Rest= external intercostals and diaphragm contract (ribcage/sternum up/out, diaphragm flat).
  • Volume inside thoracic cavity and space increases= lowers pressure outside body.
  • All gases move from high to low pressure= air rushes into lungs.
  • Exercise: in addition, sternocleidomastoid and pectoralis minor contract (larger force).
  • Greater up/outward movement= increases volume/decreases pressure which increases breathing depth and therefore volume of air inspired.

Expiration:

  • Rest= external intercostals/diaphragm relax (lowers ribcage, sternum down and in).
  • Volume in TC and space decreases= increases pressure outside body= air forced out.
  • Exercise: internal intercostals/rectus abdominis contract (larger force of contraction).
  • Greater down and in movement; decreases volmume/increases pressure.
  • Increases breathing rate and overall volume of air expired per min.
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Respiratory system

Respiratory regulation:

  • RCC receives info from sensory nerves + sends direction through motor nerves to change rate of respiratory muscle contraction.
  • IC stimulates inspiratory muscles to contract at rest and during exercise.
  • EC is inactive at rest but stimulates additional expiratory muscles to contract when exercising.

Respiratory regulation at rest:

  • At rest, IC is responsible for cycle of breathing; nerve impulses generated and stimulate inspiratory muscles making them contract via the: intercostal nerve to external intercostals and the phrenic nerve to the diaphragm.
  • Thoracic cavity volume increases, lowering lung air pressure.
  • EC is inactive at rest due to natural relaxation of diaphragm and external intercostals.
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Respiratory system

Respiratory regulation during exercise:

  • Sensory nerves relay info to RCC where a response is initiated by IC and EC.
  • RCC is chemosensitive- chemoreceptors pick up an increase in blood acidity/CO2 and decrease in O2 concentration.
  • Thermoreceptors inform of increased blood temp.
  • Proprioceptors inform of motor activity in muscles and joints.
  • Baroreceptors inform of the state of lung inflation.
  • The neural stimuli above inform the IC which increases stimulation of diaphragm and external intercostals to contract with more force.
  • IC also recruits sternoclediomastoid and pectoalis minor to give a larger force of contraction to increase the depth of inspiration.
  • Baroreceptors infrom EC on extent of lung inflation; EC can recruit internal intercostals and rectus abdominus to contract; reducing TC volume, increasing lung air pressure.
  • As exercise intensity increases, the IC and EC control leads to an increased breathing rate and decreased breathing depth to maximise efficient respiration.
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