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RESPIRATORY TRACT

RESPIRATORY ORGAN

Difference  between  dry  and  wet  cough  

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Irritation of respiratory tract Due to dust or smoke

Accumulation of mucus Due to infections

The  respiratory  tract  

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Tracheal  epithelium  

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Air  enters  the  tract  through  

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Nostrils

Passes through the nasal chamber

As it passes… 1.  Warms and humidifies the inspired air. 2.  Removes and traps pathogens and

particulate matter from the inspired air. 3.  Responsible for sense of smell. 4.  Drains and clears the paranasal sinuses

and lacrimal ducts.

Larynx    

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At the opening of the trachea is present the larynx.

Larynx is the voice box.

Pharynx  and  epiglo<s  

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Passes pharynx to reach the trachea

The opening of the trachea is glottis that is guarded by epiglottis

Trachea    

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Air then enters the trachea…

Trachea has C shaped cartilagenous rings

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Inner  lining  of  trachea  

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Trachea  branches  to  form  bronchi  

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Bronchi  branches  to  form  

bronchioles  

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Bronchioles  terminate  in  sac  like  structures  -­‐  alveoli  

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Alveolus    

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Why  do  we  breathe?  

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We  need  oxygen  for…..  

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RespiraHon  in  aerobic  animals  The process of respiration involves two phases- External respiration Internal respiration.

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Respiratory  organ…..the  lung  

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Membranes  of  lung  

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lungs  

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Hilum

ProtecHng  the  lung….RIBCAGE  

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RIBCAGE…helps  in  breathing  

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MECHANISM  OF  BREATHING  

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What  happens  during  inspiraHon  and  expiraHon  

INSPIRATION      •  External  intercostal  muscles  

contract  to  make  the  ribcage  move  outwards  and  upwards.  

•  Radial  muscles  of  the  diaphragm  contract  to  make  diaphragm  flat.  

•  Volume  increases  and  pressure  and  pressure  decreases.  

•  Air  rushes  in.  

EXPIRATION  •  Internal  intercostal  muscles  

contract  so  that  ribcage  moves  downwards  and  inwards.  

•  Circular  muscles  of  diaphragm  contract  to  make  it  dome  shaped  

•  Volume  of  thoracic  cavity  decreases  and  pressure  inside  increases.  

•  Air  is  forced  out.  TGESBIOLOGY ISC 11

External  Respiratory  exchange  

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Transport  of  respiratory  gases  •  98%  of  oxygen  is  bound  to  

hemoglobin  as  oxyhemoglobin.  •  Each  hemoglobin  molecule  has  the  

capacity  to  bind  with  four  oxygen  molecules.  

•  70%  of  CO2  is  transported  in  the  plasma  as  bicarbonate  ion.  

•  23%  of  CO2  is  bound  to  the  globin  part  of  hemoglobin  as  carbaminohaemoglobin.  

•  7%  is  dissolved  in  the  plasma.  

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Respiratory  cycle  

•  One  inspiraHon  and  one  expiraHon  alternately  is  called  respiratory  cycle.  

•  Rate  of  respiraHon  is  expressed  in  terms  of  venHlaHon  rate.  Average-­‐  12  to  14  Hmes.  

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Pulmonary  air  volumes  •  Tidal  volume-­‐  500ml  •  IRV-­‐  2000-­‐3000ml  •  ERV-­‐  1000-­‐1500ml  •  Vital  capacity-­‐  4500ml  •  Residual  volume-­‐  1500ml  •  FRV-­‐  2500ml  •  Dead  space  •  Total  lung  capacity-­‐  5000-­‐6000ml  

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Respirometer  and  spirogram  

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Tidal volume

ComposiHon  of  air    GAS     INSPIRED  AIR   ALVEOLAR  AIR   EXPIRED  AIR  

Oxygen   20.96%  by  volume  

13.6%  by  volume   15.7%  by  volume  

Carbon  di  oxide  

0.04%  by  volume   5.3%  by  volume   3.6%  by  volume  

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Transport  of  oxygen  •  Dissolved in the

plasma: This accounts for very less amounts of oxygen.

•  As Oxyhaemoglobin: oxygen diffuses into the RBC and combines with Fe ions of Haemoglobin to form oxyhaemoglobin.

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Structure of oxyhaemoglobin

Oxygen-­‐  hemoglobin  dissociaHon  curve  (oxygen  dissociaHon  curve)  

•  The  amount  of  oxygen  that  can  bind  with  Hb  is  determined  by  O2  tension.  

•  %  of  Hb  that  is  bound  with  O2  is  called  percent  saturaHon  of  Hb.  

•  This  percentage  saturaHon  of  Hb  with  O2  is  expressed  graphically  by  a  curve  called  the  O2-­‐Hb  dissociaHon  curve  or  O2  dissociaHon  curve.  

•  This  is  sigmoid  in  shape.  

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% O

2 sa

tura

tion

with

Hb

P O2 (mm Hg)

BOHR  effect:    The  decrease  in  O2  affinity  of  Hb  when  the  pH  of  blood  falls  is  called  the  Bohr  effect.  

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Transport  of  carbon-­‐di-­‐oxide  •  Carbon  di  oxide  is  transported  in  three  forms:  

– As  simple  soluHon  dissolved  in  the  plasma.  – As  bicarbonate  –  CO2  reacts  with  water  to  form  carbonic  acid,  catalysed  by  carbonate  anhydrase.  

– Carbonic  acid  dissociates  into  bicarbonates  and  hydrogen  ions.    

– Hydrogen  ions  are  picked  up  by  proteins,  some  of  the  bicarbonate  ions  remain  in  the  RBC  whereas  some  comes  out  in  the  plasma.  Chloride  ions  move  in,  this  is  called  chloride  shie  or  Hamburger  shie.  

– As  carbaminohaemoglobin  about  30%  CO2  loosely  combines  with  the  globin  part  of  deoxyhaemoglobin.  TGESBIOLOGY ISC 11

Internal  respiratory  exchange  

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Tissue cell Capillary wall Red blood cell

CO2 CO2 CO2 CO2+H2O H2CO3

CO2+Hb HbCO2 Carbonic anhydrase

HCO3+ H

Hb.O2+ H O2 + H. Hb O2 O2 O2

Cl

Cl HCO3

Chloride shift

External  respiratory  exchange  

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O2 O2 O2 O2 + H. Hb Hb.O2+ H

HCO3+ H H2CO3 CO2+H2O CO2 CO2 CO2

CO2+Hb HbCO2

Alveolus Pulmonary capillary wall Red blood cell

Carbonic anhydrase

Cl

Cl HCO3

Reverse Chloride shift

Release  of  CO2  in  lung  •  When  deoxygenated  blood  reaches  the  lung  there  is  a  difference  in  parHal  pressure  of  the  CO2  in  the  lungs  and  the  capillaries.  

•  A  series  of  reacHons  also  takes  place  as  Hb  takes  up  O2,  the  bicarbonate  reacts  with  H+  and    forms  carbonic  acid,  which  splits  into  CO2  and  water.  

•  Binding  of  O2  with  Hb  tends  to  displace  CO2  from  the  blood.  This  effect  is  called  Haldane  effect.  

•  Haldane  effect  results  from  the  fact  that  combinaHon  of  O2  with  Hb  causes  Hb  to  be  a  stronger  acid.  Thus  displaces  CO2.  

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Respiratory  diseases  

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Asphyxia  and  hypoxia  

•  Asphyxia  is  caused  by  interrupHon  in  the  supply  of  oxygen  to  the  Hssues.  – Drowning,  pneumonia,  CO  poisoning.    

•  Hypoxia  is  a  condiHon  of  shortage  of  oxygen  in  the  Hssues.  – High  alHtudes,  anemia.  

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Occupa4onal  Lung  Diseases    

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Examples  of  inorganic  dust  diseases  

•  Asbestosis  Asbestosis  is  caused  by  the  inhalaHon  of  microscopic  fibers  of  asbestos.  

•  Coal  worker's  pneumoconiosis  Coal  worker's  pneumoconiosis  is  caused  by  inhaling  coal  dust.  Also  known  as  black  lung  disease  or  anthracosis,  the  condiHon,  in  severe  cases,  is  characterized  by  scarring  on  the  lungs    

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Examples  of  inorganic  dust  diseases  

SILICOSIS    

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Examples  of  inorganic  dust  diseases  •  Berylliosis  

Berylliosis  (or  beryllium  disease)  is  caused  by  the  inhalaHon  of  beryllium  parHcles,  dust  or  fumes.  Its  symptoms  include  coughing,  shortness  of  breath,  faHgue,  weight  loss  or  loss  of  appeHte,  fever  and  sweaHng.  

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Examples  of  organic  dust  diseases  •  Byssinosis  is  caused  by  dust  from  hemp,  flax,  and  cojon  processing.  Also  known  as  brown  lung  disease,  the  condiHon  is  chronic  and  characterized  by  chest  Hghtness  and  shortness  of  breath.    

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n  Occupa4onal  asthma  n  OccupaHonal  asthma  is  caused  by  inhaling  certain  irritants  in  the  workplace,  such  as  dusts,  gases,  fumes,  and  vapors.  

Emphysema

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Emphysema •  Due to inflammation of infected lungs- phagocytes

enter the airways. •  They secrete a protein –digesting enzyme elastase. •  Elastase destroys the elastin in the wall of the alveoli. •  The alveoli are unable to stretch •  Bronchioles burst as a result of trapping of air. •  Thus reduces the surface area. •  Lung function deteriorates resulting in wheezing and

breathlessness

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Asthma    

•  All  images  have  been  downloaded  for  educaHonal  purpose  only  

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