L 06 Lab test of Asthma Flashcards
Define breathing, inspiration and expiration
Respiration is the act of breathing (gas exchange between an organism and its environment)
Inhaling is taking in oxygen
Exhaling is giving off carbon dioxide
What are the 4 functions of gas exchange?
Ventilation, capillary blood flow, diffusion of gases, of gases by blood.
Define ventilation and explain how it occurs
Ventilation is cyclical movement of air into and out of the lungs.
Occurs via contraction and relaxation of respiratory muscles using the elastic recoil of connective tissue in the lungs.
Define the diffusion of gases and explain how it occurs
The movement of O2 and CO2 from the alveolar space across into the blood. Occurs via a concentration gradient
Explain the importance of capillary flow
An adequate capillary flow to the lungs is required for adequate gas exchange, to maintain the concentration gradient.
How are gases carried in the blood? How are they released?
CO2 and O2 are bound to Hb and released by a pressure gradient.
Define alveolar ventilation
The movement of gas from the lungs to the blood (basically diffusion)
What factors can affect ventilation?
Any disease that inhibits elastic recoil can affect ventilation
- e.g obstructive diseases (asthma, COPD) affect inspiratory rate
- e.g restrictive diseases (pulmonary fibrosis) affect inspiratory capacity
Examples of obstructive diseases
Asthma, COPD, bronchitis, (emphysema)
Examples of restrictive diseases
Pulmonary fibrosis, interstitial lung disease
Diseases that affect gas diffusion
Pneumonia (difficulty reaching alveolar space) A tumour (cannot diffuse as easily across the alveolar space)
Diseases that affect pulmonary capillary flow
Pulmonary embolism
Right ventricular dysfunction.
What are the Factors that affect Hb?
AWhat affect O2 binding to Hb?
Anemia and blood loss affect hemoglobin
Arterial pH and carBon moNoxide affect O2 binding to Hb
What are hypoxia and anoxia. When may these happen?
Hypoxia- Low Oxygen in tissues.
Anoxia- No Oxygen in tissues.
May happen if any of the 4 respiratory elements are affected.
What effect will giving an oxygen mask to someone with respiratory problems have?
It will only help if ventilation is the problem (pure O2 vs air). Excess oxygen will not help diffusion occur.
Changes in which two measures cause a change in respiratory rate?
PaCO2 and PaO2 (pressure of arterial CO2 and O2)
What respiratory functions can we measure (x7)? Which can we calculate?
- Respiratory rate, pH, SaO2 (%), PaO2, PaCO2, Hb, Inspired O2
- CaO2 (arterial Oxygen content) can be calculated