Physical education paper 1

• functions of the skeletal system

  1. protection against vital organs

  2. support/ rigid bone frame that gives us our shape

  3. movement

  4. mineral storage- calcium and phosphorus stored to make bones stronger

  5. blood cell production
• types of bone

  long, short, flat, irregular
• long bones

  strong + for large muscle movement e.g. humerus, femur
• short bones

  weight bearing muscles e.g. tarsals in foot
• irregular bones

  protection + muscle attachment e.g. vertebrae of the spine
• flat bones

  protect vital organs e.g. cranium protects brain
• types of joint

  -ball and socket

  -hinge

  -pivot

  -condyloid
• ball and socket joint

  found at hip and shoulder. flexion + extension, abduction + adduction and circumduction occur here
• hinge joint


  found in elbow, knee and ankle. flexion and extension occur here
• pivot joint

  e.g. neck. rotation occurs here
• condyloid joint

  e.g. wrist. flexion and extension, abduction and adduction occur here
• tendons

  attach muscle to bone
• ligaments

  attach bone to bone
• bursae

  fluid filled sac that counters friction at a joint
• synovial fluid

  joint-lubricating fluid secreted by the synovial membrane
• cartilage

  acts as a shock absorber and a buffer between bones
• synovial membrane

  maintains the synovial fluid lubricant
• joint capsule

  the fibrous sac that encloses a joint
• purpose of synovial joints

  each part of the joint helps to allow movement and reduce the chance of injury by stopping the bones rubbing together and preventing friction
• tidal volume

  amount of air breathed in or out in a single stroke
• inspiratory reserve volume

  difference in volume from normal when we breathe in as much as we can
• expiratory reserve volume

  difference in volume from normal when we breathe out as much as we can
• residual volume


  amount of air left in the lungs after most forcible exhalation possible
• vital capacity

  the most air you can breathe in after breathing out the largest volume of air possible
• what happens within lungs after exercise

  1. tidal volume increases- deeper breaths in and out so 'peaks' are higher and 'dips' are lower

  2. breathing rate increases- more breaths taken per minute so the 'peaks' are closer together
• what is gas exchange

  the exchange of oxygen and carbon dioxide between the alveoli and bloodstream
• how is gas exchange effective

  1. large SA: there are thousands of alveoli increasing SA allowing more gas exchange to occur at the same time

  2. moist thin walls: gas can easily pass through these walls- quicker exchange

  3. lots of capillaries: they surround the alveoli meaning more exchange can take place as they carry blood

  4. large blood supply: more blood= more opportunity for gaseous exchange

  5. movement of gases: they move down the concentration gradient, co2 is forced out and o2 is forced in

  6. short diffusion distance
• where is oxygen transported from and to ?

  from the heart to the working muscles via the blood. red blood celle contain haemoglobin. oxygen combines to this substance to form oxyhaemoglobin.
• what happens during inhalation

  - external intercostal muscles contract, moving ribcage up and out

  - diaphragm contracts - flattens

  both movements increase thoracic activity forcing air into the lungs. lungs can expand more as pectorals contract, increasing volume further
• what happens during exhalation

  - intercostal muscles relax, moving ribcage in and down (internal intercostals contract)

  - the diaphragm relaxes and moves to a dome shape

  thoracic activity decreases forcing air out of the lungs. ribcage can be pulled down quicker in exercise by abdominals forcing air out quicker
• flow of deoxygenated blood


  Vena cava → right atrium → right ventricle → pulmonary artery → lungs
• flow of oxygenated blood

  lungs -> pulmonary vein -> left atrium -> left ventricle -> aorta
• stroke volume


  volume of blood pumped with each heartbeat by each ventricle of the heart
• cardiac output


  volume of blood pumped by each ventricle per minute
• calculation for cardiac output

  stroke volume x heart rate
• redistribution of blood flow (vascular shunt)

  changes in exercise

  1. arteries widen to stop blood pressure getting too high during exercise

  2. arteries supplying to working muscles vasodilate to increase blood supply to muscle

  3. arteries supplying inactive organs vasoconstrict to restrict the amount of blood being belivered

  the amount of blood depends on the intensity of the exercise
• capillaries


  carry blood through the body to exchange gases and nutrients
• structure of capillaries

  1. thin walls = easy passage

  2. narrow: lots fit into the body, larger SA

  3. blood flows through them slowly to increase time for gaseous exchange
• veins

  blood vessels that carry blood back to the heart
• structure of veins

  1. valves to prevent backflow of blood

  2. low pressure, thinner walls and less muscle

  3. wide lumen