Anatomy and Physiology

  • Created by: Fran99
  • Created on: 19-01-16 12:16

Slow Twitch Muscle Fibres

  • Red colour.
  • Slow speed of contraction.
  • Used in aerobic exercise, so use large amounts of oxygen.
  • Used for endurance activities.
  • They have a high resistance to fatigue.
  • they have a small force in their contractions.
  • Smaller muscles.
  • High mitochondria density.
  • High myglobin content.
  • High capillary density.
  • Low glycogen store.
  • High aerobic capacity.
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Fast Twitch Muscle Fibres

  • White colour.
  • Fast speed of contraction.
  • Used for anerobic exercise, so has a small oxygen use.
  • Used in speed/strenght activities.
  • Low resistance to fatigue.
  • High force of contraction.
  • Bigger muscles.
  • Low mitochondria density.
  • Low myoglobin content.
  • Low capillary density. 
  • High glycogen stores.
  • High anerobic capacity.
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Muscle Contractions

When ever a muscle contractions it comes under tension.

Isotonic Contraction: This is when movememtn occurs and the muscle is under tension. There are two different types of isotonic contractions:

  • Concentric Contraction: This is where tension is produced while the muscle shortens, and causes movement. It is normally the agonist muscle.
  • Eccentric Contraction: This is where tension is produced while the muslce shortens and controls the movement. It is normally the antagonist muscle. 

Isometric Contraction: This is tension is developed in the muscle but no joint movement occurs.

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Effects of a warm up on the skeletal muscle tissue

  • A reduction in muscle visosity (thickness) leading to an improvment in the efficiency of muscle, this is due to the increase in muscle temperature.
  • Muslce temperature increases, giving a grater speed and force of contraction.   
  • Increase delievery in O2, meaning muscle become more effective.
  • Increase speed of neural transmitters.
  • Increase elasiticity of the muscles.
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Effects of a cool down on the skeletal muscle tiss

  • Recovery time decreses.
  • Prevent blood pooling. (Blood pooling is the tendance of your cardiac output to be delivered to the muscles that have been working.)
  • Decrease risk of DOMS. 
  • An increase in the speed of removal of lactic acid and carbon dioxide.
  • Maintian flexability of muscles.
  • Optimises the adaptation process.
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Long Term Effects on the Skeletal System

Increase Bone Density

  • Due to an increase in calcium deposits.
  • Less likely to fracture bones.
  • Less likely to break bones.
  • If there are no injuires there is no reversability.
  • If bones are broken, they grow back weaker.
  • This leads to osteoprosis.  
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Long Term Effects on the Skeletal System

Thickening of the Articular Cartilage

  • Joints can absorb more force.
  • Less likely to wear away.
  • This will decrease the risk of bone spurs.
  • Less chance of osteoarthritus.
  • Good posture and aligment.
  • Less likely to suffer lower back pain.
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Long Term Effects on the Skeletal System

Increase Joint Stability

  • Ligaments increase in strength.
  • Reduce chance of a dislocation.
  • Less chance of reversability. 
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Long Term Effects on the Skeletal System

Weight Maintenance (Less likely to suffer from obesity)

  • Less weight and pressure on joints.
  • Less likley to have A.C wear away.
  • Less risk of bone spurs.
  • Less risk of osteoarthritus.
  • increase strength of liagments.
  • Reuction of flexability.
  • More likely to break/snap.
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Long Term Effects on the Skeletal System

Increase Risk of Osteoarithritus

  • Wears away A.C
  • Causing bones to rub togehter, causing synovial fluid to be lost.
  • Pain and Swelling.
  • Increas friction.
  • Increase risk of bone spurs, at the knee, hip, shoulder, and ankles.
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Long Term Effects on the Skeletal System

  • Runner's Knee: Inflame tendon found under the knee.
  • Osgood Schlatters
  • Shin Splints: Turns into a stress fracture.
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Biomachanics: Motion

Linear: Motion along a line.

  • This can be straight or curved.
  • e.g. the flight path of a shot putt after release.

Angular: Motion around a fixed point.

  • e.g. The arm movement of frontcrawl.

General: Mixture of both Linear and Angualr Motion.

  • e.g. Javelin
  • torso= Linear motion, Non throwing arm moves around shoulder joint= Angular motion.
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Biomachanics: Stability

  • Relates to how difficult it is to disturb a body from a balanced position.
  • An athlete who is kneeling on all fours is more stable than an athlete who is standing on one foot, because the first will require a greater forve to them over.
  • The stability is determinded by a number of principles that depend on the following:
  • Position of centre of mass.
  • Position of line of gravity.
  • Size of the area of support.
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Biomachanics: Force

  • Creates movement.
  • Change shape of object.
  • Causes acceleration or decleration.

Direct Force

  • Applied through centre of mass.
  • Creates linear motion.

Ecentric (off centre) Force

  • Force applied off centre.
  • Creates angular motion.
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Biomachanics: Newton's Laws

1. Law of Inertia: An object in a state of rest untill acted unpoon by an external force. e.g. a Penalty Kick

2. Law of Acceleration: When a force acts on an object, the rate of change of momentum experinceed by the object is proportional to the size of the force and takes place in the direction in which the force acts. 

3. Law of Equal or Opposit Reaction: For every action there is an equal or opposit reaction --> Whenever an object exerts a force on another, there will be an equal or opposit reaction exterted by the second on the first.

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Heart Rate

The number of times the heart beats per mintue. (bpm)

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Stroke Volume

The volume of blood ejected out of the heart in one beat. (ml)

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Cardiac Output

The volume of blood ejected by the heart in one mintue.(L/min)

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Heart's Conduction System (MyPEExam Video 17)

1) Sino-atrial node (SA) initiates the stimulus. Causes atrium to contract (atrial systole) and forces blood downwards into ventrical. Atrial systole occurs from upper to lower parts of atrium, so forces blood downwards.

2) Atrio-ventricular node (AV) recieves the impulse from the SA node, this then relays another signal.

3) The impulse travels up the Bundle of His, the signla is then seperated and travels down the purkinje fibres, this cause the ventricals to contract (venticular systole) this forces blood out of the heart either through the pulmonary atrey or the aorta.

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Double Loop Circulation

  • Deoxygentated blood returns to heart via vena cava into the right atruim
  • Atrial systole = Blood travels through tricuspid valve into right ventricle.
  • Ventricular systole = Blood forced out of heart through pulmonary artery to the lungs.
  • At the lungs gases exchange will happen. It is external diffusion.
  • Oxygenated blood returns to heart via pulmonary vein and goes to the left atrium.
  • The blood fills the left ventricle when the is ventricle diastole and atrium systole.
  • Travels throuh bicuspid valve.
  • When the left ventricle contracts it forces the blood out of the heart through the aorta and is sent to the rest of the body.
  • Pulmonary Circuit = Lungs and back.
  • Systemic Circuit = Body and back.
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Maintenance of Venous Return

  • Pocket Valves: One way valves in the veins prevent backflow of blood and direct it towards the heart.
  • Muscle Pump: Veins are situated between skeleta muscles, which when contracting and relaxing help to push or squeez blood back towards the heart.
  • Respiratory Pump: During exercise breathing becomes deeper and/or faster, which causes pressure changes in the thorax and abdomen. this increases the pressure in the abdomen, squeezing the large veins in that area and helping force the blood back to the heart.
  • Smooth Muscles: Contraction and relaxation of smooth muscles in the middle layer of the vien walls also helps to push blood through the veinsand towards the heart.gravity: Blood from the upper body is aided by gravity as it descends to the heart. 
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Mechanics of Breathing - Breathing at rest


1) Muslces = Diaphragm and external intercostal muslces contract. (Diaphragm flatterns)

2) Rib Cage = Rib cages moves up and out

3) Thoracic cavity volume = Increased volume of the thoraci cavity

4) Thoracic cavity pressure = Decreased pressure of thoracic cavity

5) Pressure gradient = Air pressure in the lungs is lower than atmospheric pressure

6) Movement of air = Air rushes in 

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Mechanics of Breathing - Breathing at rest


1) Muscles = Diaphragm and external intercostal muscles relax

2) Rib Cage = Rib cage moves down and in

3) Thoracic Cavity Volume = Decreased volume of the thoracic cavity

4) Thoracic Cavity Pressure = Increasedpressure of thoracic cavity

5) Pressure Gradient = Air pressure in the lungs is higher than atmospheric pressure.

6) Movement of Air = Air rushes out 

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Respiratory System

  • Pulmonary Ventilation: the breathing of air into and out of the lungs
  • External Respiration: Exchange of oxygne and carbon dioxide between the lungs and blood.
  • Internal Respiration: Exchange of oxygen and cardon dioxide between the blood and the muscle tissue
  • Diffusion Gradient: The difference between high and low pressure
    • The stepper the slide the faster you go, so the the steeper the diffusion gradient the faster diffusion will occur.
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