• Created by: Zina_
  • Created on: 30-04-18 16:23

what is the composition of atmospheric air

78% N2

21% O2 

0.04% CO2 

oxygen has an atmospheric pressure of 760mmHg, with is contributing to 21% of the atmosphere.What is the partial pressure?

0.021x760= 159mmHg

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compare exhalation and inhalation


  • diaphragm relaxes and moves up 
  • chest contracts, rib cage moves down 
  • thoratic value restored by elastic recoil of the diaphragm 


  • diaphragm contracts and moves down 
  • chest expands, rib cage moves up and out = enlarging thoratic cavity 
  • lung pressure decreases, air comes rushing in = inflating them 
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what is the respiration quotient equation?

RQ= volume of CO2 produced/volume of 02 consumed 

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what is meant by surface tension?

=pressure exerted upon the alveoli to make them collapse, lines the alveoli reducing surface tension increasing compliance and preventing them from collapsing 

compliance = lungs ability to stretch, representing the change in volume that occurs for a given change in pressure 

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how is respiration controlled by the neuronal syst

  • phrenic major nerve on the 3rd,4th,5th cervical segments of the spinal cord
  • peripheral chemoreceptors in the aorta/carotid arteries detect -o2/+co2/+H+
  • central chemoreceptors in the brainstem/medulla detect +CO2/+H+
  • cerebral cortex controls voluntary respiration 
  • stretch receptors in the lungs
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what are the partial pressure values


  • oxygen- 40mmHg
  • co2- 46mmHg


  • oxygen - 100mmHg
  • co2- 40mmHg


  • oxygen- 100mmHg
  • co2- 40mmHg


  • oxygen - 40mmHg
  • co2- 46mmHg
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how is carbon dioxide transported?

  • as bicarbonate ions(HCO3-), co2 combines with water=H2CO3= HCO3_+H+
  • dissolved in the plasma 
  • binds to Hb/plasma proteins 
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how does altitude effect respiration?

  • high altitude= reduced partial pressure of oxygen= Hb less saturated= respiration cant provide sufficient ATP= increased ventilation


  • increased red blood cells 
  • increased myoglobin conc 
  • increased mitochondria conc
  • larger chest size 
  • increased respiratory enzymes 
  • more dense alveoli= larger SA 
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draw a volume/time graph for obstructive lung dise

  • FEV1<80%
  • FVC not usally reduced
  • ratio<0.7
  • asthma, pulmanory disease, chronic bronchitis, emphysema 
  • Image result for obstructive graph
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draw the graph of restrictive disease

Image result for restrictive graph

  • FEV1<80%
  • FVC<80%
  • ratio normal 
  • ratio>0.8
  • fibrosis, tumours, pneumothorax
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respiration graph

Image result for lung volume graph

  • tidal volume= normal resting breathing
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describe the gas exchange

Image result for transport of oxygen diagram

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describe the gas exchange

Image result for transport of oxygen diagram

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haemoglobin curve graph

  • Image result for hemoglobin curve ( binging - affinity for oxygen increases as more ligand bound 
  • left shift: inc pH,dec CO2,dec temp
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