Respiratory Flashcards
What gases go in and out in the pulmonary and systemic circuit?
Pulmonary- oxygen in and co2 out.
Systemic- co2 in and oxygen out.
Why is co2 more diffusible in blood than o2?
The pressure gradient of oxygen is greater than co2.
What is the metabolic co2 and o2 level?
co2-40ml/L
o2-50ml/L
What are the anatomical and physical properties of the respiratory system that allow for gas diffusion?
- large surface area for gas exchange
- large partial pressure gradients
- gases with advantageous diffusion properties
- specialised mechanisms for transporting gases between lungs and tissues
How do you calculate the total pressure?
Partial pressure (pressure of one particular gas) + Tensions of gas.
What measurement (mmHg) is atmospheric sea level pressure (barometric pressure)?
760mmHg.
How do you calculate the partial pressure of a gas?
Partial pressure of gas (Pgas) = fraction of gas (Fgas) in gas mixture x barometric pressure (Pb).
What is the partial pressure of water vapour at body temp?
47mmHg.
*PIO2 = (Pb – PH2O) x FO2
= (760 – 47 mmHg) x 0.21
=150 mmHg or torr IN TRACHEA
For each mmHg of PO2 there is what volume of 0xygen in 100ml of blood?
For each mmHg of PO2 there is 0.003ml O2/100 ml blood. Arterial blood (PaO2) = 100mmHg: contains 0.3 ml O2/100ml blood (3ml O2/litre of blood).
What is the cardiac output for strenuous exercise (L/min)?
30L/min.
Why do we need more oxygen in the blood that is not dissolved?
Arterial blood contains 3ml O2/litre of blood x 30 (CO) = 90 ml/min.
BUT tissue requirements may need 3000 ml O2/min.
Second O2 transport system in place: Haemoglobin.
Revise haemoglobin.
2 alpha, two beta chains.
Iron in reduced form- this is where oxygen binds.
280 billion haem in a red blood cell.
Red blood cells only in capillary for one second.
What is the effect of pH and temperature on binding of haem?
- pH- CO2 released in a pH7.2, CO2 causes more acidity and O2 unbinds from haem.
- temperature- lungs are at a slightly lower temp which causes o2 to bind to haem. O2 dissociates at a high temperature.
Describe the flat and steep portion of the sigmoid oxygen dissociation curve?
The drop from 100-60mmHg has minimal effect on the saturation.
The steep portion of the curve there was a large volume of oxygen released with only a small change in PO2 into tissues.
How many g of haem binds with 1.39ml of oxygen and what is the normal level of haem binding with O2 in blood (Hb/100ml)?
1g.
15 Hb/100ml of blood.
O2 capacity is 20.8ml O2/100ml blood.
What is the normal level of CO2 produced in ml/min?
200ml/min.
What is the respiratory exchange ratio?
100 O2 in, 80 CO2 out.
What are the percentages of co2 found in the body in three different forms?
dissolved- 7% plasma
haem bound- 23%
bicarbonate- 70%.
Acidity of the blood is regulated by what?
Kidneys and ventilation to adjust PCO2.
CO2 to bicarb pathway regulates the acidity and plays an important trole in the acid base balance of the blood by adjusting H+ ions.
What is the rest, walking and severe exercise exchange of oxygen and co2 per minute?
Rest- 250ml/min. 200ml/min
Walking- 800. 750
Sever exercise- 5000 6000
What is included within the upper airways?
Nasal cavity, paranasal sinuses, pharynx and larynx.
How many cilia are on one epithelial cell?
250.
How does the upper airways get rid of debris?
The rhythmic beating of cilia moves particles upwards.
What is active inspiration and passive expiration? (quiet breathing)
ai- diapharm moves down and out and the thoracic cavity lengthens.
pe- elastic recoil, no energy is required. Intercostal muscles relax.
What are the inspiratory accessory active muscles called?
sternocleidomastoid- attaches onto sternum and pulls outwards, alae nasi- nostrils to flare, genioglossus-moves tongue away from back of mouth.
What are the muscles of expiration?
internal intercostal muscles (apart from parasternal intercartilagneous muscle), abdominal muscles (rectus abdomens, internal/external oblique and traverses abdomenus).
What are the muscles of inspiration?
sternocleidomastoid, scalenous, parasternal intercartilagenous muscle, external intercostal and the diaphragm,
Why does the pleural cavity have a more negative pressure with respect to interpulmonary pressure?
To keep alveoli open and to cause the lungs to not collapse.
