Respiration

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

EXHALATION:

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

INSPIRATION:

• 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 

RQ= volume of CO2 produced/volume of 02 consumed 

=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 

• 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

PULMANORY ARTERIES:

• oxygen- 40mmHg
• co2- 46mmHg

PULMANORY VEINS:

• oxygen - 100mmHg
• co2- 40mmHg

SYSTEMIC ARTERIES:

• oxygen- 100mmHg
• co2- 40mmHg

SYSTEMIC VEINS:

• oxygen - 40mmHg
• co2- 46mmHg

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

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

ADAPTATIONS TO HIGH ALTITUDE CONDITIONS:

• increased red blood cells 
• increased myoglobin conc 
• increased mitochondria conc
• larger chest size 
• increased respiratory enzymes 
• more dense alveoli= larger SA 

• FEV1<80%
• FVC not usally reduced
• ratio<0.7
• asthma, pulmanory disease, chronic bronchitis, emphysema 
• 

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

• tidal volume= normal resting breathing

• cooperative binging - affinity for oxygen increases as more ligand bound 
• left shift: inc pH,dec CO2,dec temp