Topic list 3 Flashcards
What is residual volume?
air remaining in the lungs after complete exhalation
What are the standard capacities?
inspiratory capacity, functional residual capacity, vital capacity, total lung capacity
What is functional residual capacity?
volume of air at the end of exhalation during normal breathing
What is vital capacity?
Total volume of exhaled air from max inspiration to max expiration
What is total lung capacity?
total volume of air in the lung at the end of max inspiration
What is the pressure at the base of the pleural cavity?
-2.5 cm H20
What is the pressure at the apex of the pleura cavity?
-10 cm H20
When are the lungs the smallest?
when transpulmonary pressure = 0
What is emphysema?
Loss of alveoli and of their elastic tissue
What type of system is the pulmonary circulation?
Low pressure / low resistance system
Where is the ventilation / perfusion ratio at its lowest?
at the bottom of the lung, where Q exceeds Va
What does Graham’s law state? (2)
rate of diffusion of a liquid is proportional to its solubility, and inversely proportional to the sqrt of its molecular weight
What is special about the gamma sub-unit of fetal Hb?
It does not bind to 2,3BPG and thus has increased affinity for O2
What is the O2 dissociation curve?
curve that illustrates the relationship bw pO2 in blood and number of O2 molecules bound to Hb
When is the Hgb saturation especially dependant on pO2?
under 60mmHg pO2
What is the P50 value of O2-Hb binding for a physiological adult?
27mmHg
What is the Haldane effect?
oxygenation of blood in the lung displaces O2 from Hgb, which increases the removal of CO2 - oxygenated blood has reduced affinity for CO2
What are the 4 types of hypoxia?
- hypoxic hypoxia
- anaemic
- circulatory
- histotoxic
What is the max breathing capacity?
160L/min
What is the actual pulmonary ventilation during maximal exercise?
110L/min
What does Boyle’s law state?
the volume to which a given quantity of gas is compressed is inversely proportional to the pressure (P1V1=P2V2)
What are the 4 things that control breathing?
- neural control centers
- chemoreceptors
- mechanoreceptors
- brain stem (respiratory muscles)
What are the 3 centres of the brainstem that control breathing?
- medullary center
- apneustic center
- pneumotaxic
Where are mechanoreceptors found? (5)
- In the lung tissue
- Joints and muscles
- Alveolar wall
- Epithelial cells of the airways
