Oxygenation and Ventilation Flashcards
Gas Exchange
oxygen transport to the cells and carbon dioxide transport away from cells through ventilation and diffusion
Ventilation
movement of atmospheric air higher in oxygen into the lungs and the removal of the carbon dioxide produced by metabolism.
Diffusion
the movement of gases down their concentration gradients across the alveolar and capillary membranes
Perfusion
the arterial blood flow through the tissues
PO2 and PCO2 of venous blood
PO2 = 40
PCO2 = 46
PO2 and PCO2 at alveoli
PO2 = 100
PCO2 = 40
PO2 and PCO2 at end capillary
PO2 = 100
PCO2 = 40
4 Steps of Cardiopulmonary Circulation
- Pulmonary Gas Exchange: ventilation, diffusion, perfusion
- Oxygen Delivery: effected by cardiac output, HgB levels, SaO2, PaO2
- Oxygen extraction at the tissue level
- Oxygen consumption by the mitochondria
What 4 factors effect oxygen delivery?
- cardiac output
- hemoglobin levels
- SaO2
- PaO2
Respiration
Sequence of events that results in exchange of O2 and CO2 between atmosphere and body cells
Ventilation is what we think of as _______ and stimulated by ________
breathing
nerves
External respiration
Gas exchange between lungs and blood
Internal respiration
Exchange of gasses between blood and tissue cells
Cellular respiration
Cells using oxygen for activities - metabolism
Ventilation
Flow of air in and out of the alveoli
* Inspiration & expiration
Ventilation requires intact:
- CNS (brain and spinal cord) neurons,
- diaphragm,
3, skeletal muscle (i.e. intercostal muscles), - chest thorax
In ventilation, air flows from _______ to _______ pressure
Air flows from higher to lower pressure
Capnography
Non-invasive measurement of CO2 concentration in expired gasses
* Amount of CO2 exhaled
* Continuous bedside monitoring
Diffusion
Movement of gasses (O2 & CO2) across a permeable membrane from an area of higher pressure to an area of lower pressure
What 2 places does diffusion occur?
- Alveoli: pulmonary circulation (alveolar capillary membrane)
- Capillary: tissue/cells
Diffusion is dependent on what 3 things?
- Differences in pressures
- Surface area
- Thickness of wall
Normal Female Hemoglobin
120-150 mg/dL
Normal Male Hemoglobin
135-170 mg/dL
Hemoglobin
major component of RBCs - A major carrier of oxygen in blood and an important factor in tissue oxygenation– has affinity (attraction) for oxygen
What is Sa02
Percentage of oxygen-saturated hemoglobin in arterial blood
How is Sa02 measured?
ABG
Normal SaO2
> 95%