gas exchange Flashcards
Where does gaseous exchange occur
Between alveoli and capillaries
What’s the level of Nitrogen measurable in dry air/alveolar air
79% Dry air
75% Alveolar air
What’s the level of Oxygen i’m dry air/alveolar air
21% Dry air
14% Alveolar air
What’s the level of carbon dioxide in dry air/alveolar air
- 04% Dry air
5. 3% alveolar air
What is the level of water vapour in Dry air/alveolar air
0 Dry air
6.2% alveolar air
What are the 2 types of cells lining the alveoli
Numocytes
Type 1 help with gas exchange
Type 2 store and secrete surfactant
What is haemoglobin made of
4 Globins (polypeptide chains)
4 Haem molecules
carry’s 98% of oxygen
Which is more soluble in water, oxygen or carbon dioxide?
Carbon dioxide
When is haemoglobin’s affinity with oxygen highest
After 1 haem molecules has bound with 1 oxygen molecule this changes the overall shape increasing its affinity with oxygen
What is the % of saturation when the partial pressure of oxygen is 80mmHg?
95.8%
What are the forms of transport of carbon dioxide
70% HCO3 Bicarbonate ions
23% haemoglobin
7% dissolved in plasma
How is carbon dioxide bonded with haemoglobin
CO2HB Carbino haemoglobin
Binds with the globin aspect
How is 70% carbon dioxide absorbed
Carbon dioxide binds with water to form carbonic acid. This process is assisted by the enzyme carbonic anhydrase.
This splits into hydrogen ions and bicarbonate ions which then leave the red blood cell body.
How is the ionic composition of the red blood cell maintained during absorption of carbon dioxide
Chloride shift - chloride ions with negative charge diffuse into the cell body
What happens when there is a right shift of the oxygen disassociation curve?
Reduced affinity with oxygen less oxygen is absorbed. This could be due to increased temperature, increased hydrogen ions ( if the level of carbon dioxide increases in blood cell)
This could be due to exercise
Value of oxygen in blood
Co2 in blood
O2 saturation
11-14 kpa 80-100mmhg
4-6 kpa 35-45 mmhg
98%
What is the Bohr shift
Due to increased hydrogen ions in the red blood cells haemaglobin decreases its affinity with oxygen to enable it to transport more co2 out of the body
Can be due to increased temp, exercise etc.
What is a right shift in a disassociation curve
Increased affinity to oxygen
Foetal haemoglobin
Stretch receptors
I thin smooth muscle bronchial walls — communicate to vague nerve — Dorsal respiratory group — makes inspiration shallower and shorter prevents the lungs over stretching
Juxtapulmonary receptors
Within alveoli and bronchial walls — vagus nerve — Dorsal respiratory group — Apneoa or shallower breathing
Proprioreceptors
Position/length receptors in respiratory muscles (not diaphragm)
Do2
Delivery of oxygen
Vo2
Oxygen consumption
