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UNIT 9:
RESPIRATORY SYSTEM AND
  GASEOUS EXCHANGE
BREATHING
 Sequence of events that results in gas exchange.
 In terrestrial vertebrates it includes 3 steps:
      1.     Ventilation: Inspiration and
         expiration.
      2.     External respiration: Gas exchange
         between air (in lungs) and blood.
         Blood then transport Oxygen to the
         body tissue cells.
      3.     Internal respiration: Gas exchange
         between blood and tissue fluid.
         Blood then transports carbon
         dioxide to the lungs.
Gas exhange surface
must be:                      Alveoli filled with air (gas)             External
Moist                                                                  respiration
                             Carbon dioxide                   oxygen
Thin
Large in relation of size
of body
                                                                       Blood  part of
                                                                       circulatory system
                                                                       contain red pigment 
    Process: Diffusion of                                              hemoglobin, to
    gasses (oxygen and                                                 transport gasses
    carbon dioxide




                                                                       Internal
                                                                       respination
                                     oxygen             Carbon dioxide
                                                         Body cells surrounded by tissue fluid
Cellular respiration
 Is the process whereby an organism uses
  oxygen and food to produce energy (ATP) and
  2 by products e.g. water and carbon dioxide

 Glucose + O2      ATP + H2O + CO2

Therefore gaseous exchange is necessary to get
  oxygen for cellular respiration.
HUMAN RESPIRATORY SYSTEM
 Consists of:
 1. Nose
 2. Air passages:
     Pharynx
     Trachea
     Bronchus
     Bronchioles
3. Lungs  Alveoli
 Nose has a nasal cavity that
  leads to the pharynx.
 Nasal cavity is lined with cilia
                                     NOSE
  and hairs and goblet cells that
  make mucus (anti-septic and
  moisten air) filter the air 
  dust, pollen and other foreign
  material sticks to it.
 3 x turbinate bones divide the
  nasal cavity into 4 passages 
  This enlarges the surface of the
  nasal cavity  For warming,
  cleaning and moisten of air.
 Several surface blood vessels
  help to warm air.
AIRPASSAGES
 Pharynx  pass air form
  nose to trachea via larynx.
 Trachea: long, straight
  tube kept open by C-
  shaped cartilage rings.
 Trachea  lined with cilia
  and goblet cells (mucus
  production)  traps
  foreign particles
Lining of airpassages
CILIA (SEM)   TRACHEAL LINING
AIRPASSAGES: BRONCHI AND
             BRONCHIOLES
 Trachea divides in a right
  and left bronchus 
  consist of C-shaped
  cartilage rings and lined    Right bronchus-short
  with goblet cells (mucus)    Branch in 3       Left bronchus  long,
 Bronchi branch in lung to                      branch in 2

  form bronchioles 
  branch further and
  cartilage rings disappears
   lead air to air sacs of
  lung.                                          Bronchiole
LUNGS
 Right lung (3 lobes - shorter)
  and left lung (2 lobes  longer,
  narrow)
 Spongy, elastic pink organ.
 Consists of several air sacs
  called alveoli.
 Alveoli are grouped together
  and form the endings of the
  bronchioles.
ALVEOLI
 Lined with single layer
  squamous epithelial cells 
  Thin easy diffusion of gas.
 Alveoli is surrounded by a
  network of blood capillaries 
  gasses diffuse into and out of
  blood.
 Alveoli is lined with moist
  layer  oxygen dissolves in
  moisture and diffuses through
  alveoli wall into blood
  capillary.
Pulmonary vein
                                         Pulmonary artery
                  (Oxygenated
                                         (Deoxygenated
                  blood)
                                         blood)




Turbinate bones

  Pharynx
                                                  Alveoli

  Trachea


  Bronchus


Bronchiole

Diaphragm
                                   SEM    TEM
BREATHING - The process whereby air (gasses)
                       move in and out of the body.
                                                              EXPIRATION
          INSPIRATION
   INSPIRATION                     Air inhaled
                                                  EXPIRATION                 Air exhaled
Rib cage
expands as                                Rib cage gets
rib muscles                               smaller as rib
contract                                  muscles relax




                                          When pressure in
                                          lungs increase  air is
When pressure in                          pushed out
                       Diaphragm                                    Diaphragm
lungs decrease  air
                       contracts (moves                             relaxes (moves
rush in
                       down)                                        up)
TIDAL VENTILATION MECHANISM
 Air moves in and out of the body via the same
  route.
 All terrestrial vertebrates do this except for birds.
 The lungs are not completely emptied during
  each breathing cycle.
 The air entering mixes with used air remaining in
  the lungs.
 This help to conserve water, but decreases gas-
  exchange efficiency
Determining lung capacity
 A spyrometer can be used to determine how much air
  enters the lungs.
 Your lungs has a volume of +/- 5 liters.
 During a normal breath, only 0.5 liters of air is
  exchanged  This air is known as tidal volume.
 During forced breathing, as much as 3.5 liters of air can
  be exchanged, this is known as vital capacity. (The fitter
  you are, the higher your vital capacity.)
 +/- 1.5 liters of air always remains in the lungs  this air
  is known as residual air/volume.
Respiratory system and gaseous exchange
RESPIRATORY CENTER
 Normal breathing rate for adults: 12  20
  ventilations per minute.
 Respiratory Center in the Medulla Oblongata
  of the brain controls breathing.
 The respiratory center send impulses through
  the phrenic nerve to the diaphragm and
  through the intercostal nerve to the
  intercostal muscles to either contract or relax.
  (Contract during inspiration and relax during
  expiration)
Nervous control of breathing
                     Brain


    Respiratory center automatically
    regulates breathing


      Intercostal nerves
      stimulate the
      intercostal muscles
    Intercostal muscles

Pheric nerve stimulates the
diaphragm

            Diaphragm
GAS EXCHANGE
 Gas exchange between air in
  lungs and blood
   EXTERNAL RESPIRATION          INTERNAL RESPIRATION
 Movement driven by diffusion    Gas exchange between
  gradient. ( [] to [])            blood and tissue fluid
 Gasses exerts pressure, the     Movement driven by
  amount of pressure each gas      diffusion gradient. ( [] to
  exerts is called  partial       [])
  pressure (PO2 and PCO2)         Gasses exerts pressure, the
                                   amount of pressure each
                                   gas exerts is called  partial
                                   pressure (PO2 and PCO2)
EXTERNAL RESPIRATSION
 If PO2 differs across a membrane  oxygen will
  diffuse from a high to a low pressure.
 If PCO2 differs across a membrane  carbon
  dioxide will diffuse from a high to a low
  pressure.
 During inspiration the alveoli fills with air 
  higher PO2 and lower PCO2 than blood.
 Oxygen diffuse from alveoli into blood and
  carbon dioxide diffuse from blood into alveoli.
INTERNAL RESPIRATION
 When blood reaches the tissue, cellular
  respiration in cells causes the tissue fluid to
  have a lower PO2 and a higher PCO2 than the
  blood.
 Thus oxygen diffuse from a high pressure in
  the blood to a low pressure in the tissue fluid
  and eventually in the tissue cells.
 Carbon dioxide diffuse from a high pressure in
  the tissue fluid to a low pressure in the blood.
Respiratory system and gaseous exchange
TRANSPORT OF OXYGEN
 Most oxygen is transported by hemoglobin
  (red pigment protein in erythrocytes).
 Oxygen combines with hemoglobin to form
  oxyhemoglobin.
      Hb         +    O2 =       HbO2
  Hemoglobin        Oxygen      Oxyhemoglobin
 A small amount of oxygen is transported in
  solution in the blood plasma.

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Respiratory system and gaseous exchange

  • 1. UNIT 9: RESPIRATORY SYSTEM AND GASEOUS EXCHANGE
  • 2. BREATHING Sequence of events that results in gas exchange. In terrestrial vertebrates it includes 3 steps: 1. Ventilation: Inspiration and expiration. 2. External respiration: Gas exchange between air (in lungs) and blood. Blood then transport Oxygen to the body tissue cells. 3. Internal respiration: Gas exchange between blood and tissue fluid. Blood then transports carbon dioxide to the lungs.
  • 3. Gas exhange surface must be: Alveoli filled with air (gas) External Moist respiration Carbon dioxide oxygen Thin Large in relation of size of body Blood part of circulatory system contain red pigment Process: Diffusion of hemoglobin, to gasses (oxygen and transport gasses carbon dioxide Internal respination oxygen Carbon dioxide Body cells surrounded by tissue fluid
  • 4. Cellular respiration Is the process whereby an organism uses oxygen and food to produce energy (ATP) and 2 by products e.g. water and carbon dioxide Glucose + O2 ATP + H2O + CO2 Therefore gaseous exchange is necessary to get oxygen for cellular respiration.
  • 5. HUMAN RESPIRATORY SYSTEM Consists of: 1. Nose 2. Air passages: Pharynx Trachea Bronchus Bronchioles 3. Lungs Alveoli
  • 6. Nose has a nasal cavity that leads to the pharynx. Nasal cavity is lined with cilia NOSE and hairs and goblet cells that make mucus (anti-septic and moisten air) filter the air dust, pollen and other foreign material sticks to it. 3 x turbinate bones divide the nasal cavity into 4 passages This enlarges the surface of the nasal cavity For warming, cleaning and moisten of air. Several surface blood vessels help to warm air.
  • 7. AIRPASSAGES Pharynx pass air form nose to trachea via larynx. Trachea: long, straight tube kept open by C- shaped cartilage rings. Trachea lined with cilia and goblet cells (mucus production) traps foreign particles
  • 8. Lining of airpassages CILIA (SEM) TRACHEAL LINING
  • 9. AIRPASSAGES: BRONCHI AND BRONCHIOLES Trachea divides in a right and left bronchus consist of C-shaped cartilage rings and lined Right bronchus-short with goblet cells (mucus) Branch in 3 Left bronchus long, Bronchi branch in lung to branch in 2 form bronchioles branch further and cartilage rings disappears lead air to air sacs of lung. Bronchiole
  • 10. LUNGS Right lung (3 lobes - shorter) and left lung (2 lobes longer, narrow) Spongy, elastic pink organ. Consists of several air sacs called alveoli. Alveoli are grouped together and form the endings of the bronchioles.
  • 11. ALVEOLI Lined with single layer squamous epithelial cells Thin easy diffusion of gas. Alveoli is surrounded by a network of blood capillaries gasses diffuse into and out of blood. Alveoli is lined with moist layer oxygen dissolves in moisture and diffuses through alveoli wall into blood capillary.
  • 12. Pulmonary vein Pulmonary artery (Oxygenated (Deoxygenated blood) blood) Turbinate bones Pharynx Alveoli Trachea Bronchus Bronchiole Diaphragm SEM TEM
  • 13. BREATHING - The process whereby air (gasses) move in and out of the body. EXPIRATION INSPIRATION INSPIRATION Air inhaled EXPIRATION Air exhaled Rib cage expands as Rib cage gets rib muscles smaller as rib contract muscles relax When pressure in lungs increase air is When pressure in pushed out Diaphragm Diaphragm lungs decrease air contracts (moves relaxes (moves rush in down) up)
  • 14. TIDAL VENTILATION MECHANISM Air moves in and out of the body via the same route. All terrestrial vertebrates do this except for birds. The lungs are not completely emptied during each breathing cycle. The air entering mixes with used air remaining in the lungs. This help to conserve water, but decreases gas- exchange efficiency
  • 15. Determining lung capacity A spyrometer can be used to determine how much air enters the lungs. Your lungs has a volume of +/- 5 liters. During a normal breath, only 0.5 liters of air is exchanged This air is known as tidal volume. During forced breathing, as much as 3.5 liters of air can be exchanged, this is known as vital capacity. (The fitter you are, the higher your vital capacity.) +/- 1.5 liters of air always remains in the lungs this air is known as residual air/volume.
  • 17. RESPIRATORY CENTER Normal breathing rate for adults: 12 20 ventilations per minute. Respiratory Center in the Medulla Oblongata of the brain controls breathing. The respiratory center send impulses through the phrenic nerve to the diaphragm and through the intercostal nerve to the intercostal muscles to either contract or relax. (Contract during inspiration and relax during expiration)
  • 18. Nervous control of breathing Brain Respiratory center automatically regulates breathing Intercostal nerves stimulate the intercostal muscles Intercostal muscles Pheric nerve stimulates the diaphragm Diaphragm
  • 19. GAS EXCHANGE Gas exchange between air in lungs and blood EXTERNAL RESPIRATION INTERNAL RESPIRATION Movement driven by diffusion Gas exchange between gradient. ( [] to []) blood and tissue fluid Gasses exerts pressure, the Movement driven by amount of pressure each gas diffusion gradient. ( [] to exerts is called partial []) pressure (PO2 and PCO2) Gasses exerts pressure, the amount of pressure each gas exerts is called partial pressure (PO2 and PCO2)
  • 20. EXTERNAL RESPIRATSION If PO2 differs across a membrane oxygen will diffuse from a high to a low pressure. If PCO2 differs across a membrane carbon dioxide will diffuse from a high to a low pressure. During inspiration the alveoli fills with air higher PO2 and lower PCO2 than blood. Oxygen diffuse from alveoli into blood and carbon dioxide diffuse from blood into alveoli.
  • 21. INTERNAL RESPIRATION When blood reaches the tissue, cellular respiration in cells causes the tissue fluid to have a lower PO2 and a higher PCO2 than the blood. Thus oxygen diffuse from a high pressure in the blood to a low pressure in the tissue fluid and eventually in the tissue cells. Carbon dioxide diffuse from a high pressure in the tissue fluid to a low pressure in the blood.
  • 23. TRANSPORT OF OXYGEN Most oxygen is transported by hemoglobin (red pigment protein in erythrocytes). Oxygen combines with hemoglobin to form oxyhemoglobin. Hb + O2 = HbO2 Hemoglobin Oxygen Oxyhemoglobin A small amount of oxygen is transported in solution in the blood plasma.