Respiratory two

  1. Gas exchange
    >all gas exchange occurs via diffusion

    > two processes; internal and external respiration
  2. Internal respiration
    • >The exchange of
    • O2 & CO2 between the systemic
    • capillaries and the body’s cells.

    • >oxygenated blood leaves the heart through Left
    • ventricle, into aorta and travels to tissue.

    • >as it reaches the capillaries, O2 diffuses out of
    • capillaries across to tissues.

    >CO2 diffuses out of tissues and into capillaries

    >Blood returns to heart via vena cava, into Right atrium

    >blood is now poor in O2 and rich in CO2
  3.  External respiration 
    • >the exchange of
    • O2 & CO2 between the capillaries
    • & Alveoli

    • >Blood leaves the heart via Right ventricle, into
    • pulmonary arteries.

    • >O2 diffuses from alveoli, across the respiratory
    • membrane & into the capillaries.

    • >CO2 diffuses from capillaries across respiratory membrane
    • to the alveoli and into lungs to be expelled

    • >  blood returns to
    • the heart via Left atrium/ pulmonary veins

    > blood is rich in O2 and poor in CO2

    >ready to be pumped into systemic circuit
  4.  Partial pressure gradient
    Is the Movement of a specific gas (O2/CO2)

    • >dependent upon concentration of gas and its solubility
    • in plasma or blood.

    >Each gas acts independently of each other

    • >Movement is either between lungs and blood or blood and
    • tissues.
  5. Oxygen transportation in blood
    • >partial pressure of O2 is higher in the alveoli where
    • concentration is higher

    • >O2 moves down its concentration gradient form the
    • alveoli into capillaries where its concentration is lower

    • >attaches to haemoglobin molecules called oxyhaemoglobin
    • (HBO2)
  6.  CO2 transportation in
    >Leaves the tissue and enters the blood as CO2

    >Is transferred in blood as bicarbonate (HCO3)

    • >moves down pressure gradient from blood to alveoli to be
    • expelled by the lungs.
  7.  Control of
    respiration in nervous system

    >NS controls breathing in the medulla and the pons

    • >Medulla sets rhythm & Pons stimulate the inhibit
    • breathing in/out

    • >Surrounding the respiratory centre is a complex
    • collection of neurons

    • >Neuron are stimulated and activate phrenic and intercostal
    • nerves responsible for stimulating the diaphragm & intercostal muscles to
    • contract and begin breathing.

    • >Impulses go back & forth to medulla to maintain
    • respiratory rate and pons to maintain depth of breathing.

    • >Relaxation of intercostals & diaphragm occurs as
    • process shut down

    • >to allow air to move out of the lungs in response to
    • elasticity of lungs as they recoil to normal size


    Other factors controlling breathing

    • >Coughing, laughing, exercising, increased body
    • temperature increase respiratory rate

    >Hypothermia- reduce/suppress respiratory rate
  8. Hypoxia

    Impaired oxygen transportation


    • >Causes include anaemia, COPD, impaired/block circulatory
    • systems.

    >Easily recognised by impaired respiration & cyanosis
  9. Carbon monoxide (CO)
    • >odourless and colourless gas that completes with O2 for
    • same binding sites on haemoglobin molecule.

    >CO poisoning is a type of hypoxia

    >signs of CO poisoning often misdiagnosed

    • > person becomes confused, headachy, skin becomes red and
    • passively looses consciousness

    > treatment involves 100% O2 to rid the body of CO2

    Chronic obstructive
    pulmonary disease (COPD)

    • >Leading cause of death and sickness as number of
    • diagnosed increased

    >Likely to affect middle to older adult

    • >Irreversible disorder that is progressive but
    • preventable disease

    > smoking is the most common cause

    • >common symptoms include fever, fatigue with increasing
    • dypsonea

    • Increasing cough, wheezing, and increase production of
    • sputum

    • >characterised by airflow obstruction caused by either
    • emphysema or chronic bronchitis or both

    • >Emphysema is characterised by breakdown of elastin &
    • collagen

    • >chronic bronchitis is characterised by excessive
    • production of mucous along with recurrent cough.

    • > high risk of dehydration, high energy requirements
    • & exhaustion
  11. Development aspects

    >Foetus – gas exchange occurs via placenta

    • >Birth- respiratory passages fill with air and alveoli
    • inflate; takes 2 weeks

    • >process dependent upon presence of surfactant – present
    • between week 28-30weeks gestation

    >Surfactant prevent alveolar from collapsing

    • >does this by decreasing surface tension within the
    • lining of the alveolar

    >gas exchange will not occur if alveoli collapse

    • >Lungs continued to mature until young adulthood- smoking
    • affect development
  12.  Respiratory rate during lifespan
    • >higher at birth and gradually decrease until normal
    • adulthood

    >rate may increase in older adult

    • >As one age, thorax becomes rigid, lungs loose their
    • elasticity and protective mechanisms become less effective making more
    • susceptible to developing respiratory infections.
Card Set
Respiratory two