Respiratory Physiology Flashcards
What is the difference between conducting zone and respiratory zone?
Respiratory zone is the site for gas exchange
Conducting zone is a passageway for airs to move in and out of lunges
What are the function of conducting zone
Pathway of air that cleans humidifies and warms air
Which cells are unique to respiratory zone?
alveolar cells
Type I = squamous epithelial cells
Type II = cubital cells
Aveolar macrophage
Outline the autonomic nerve supply to the airway smooth muscle
Sympathetic control:
- B2 adrenergic receptors =Bronchodilation
Parasympathetic control:
- M3 muscarinic receptors = Bronchoconstriction
What is respiration and what are the phases?
The process of supplying oxygen and removing CO2
1) Pulmonary ventilation
2) External Respiration
3) Gas transport
4) cellular respiration
What is intrapulmonary pressure?
the pressure in alveoli
after exhale intrapulmonary = atmospheric pressure
What is intrapleural pressure?
The pressure inside the pleural cavity
always negative to intrapulmonary pressure
What is transpulmonary pressure?
Difference between intrapulmonary and intrapleural pressure
What is Boyles law and how does it apply to respiration?
Pressure varies inversely to volume. If pressure increases volume decreases.
In respiration a vacuum effect is created, diagram contracts increasing intrapulmonary volume which decreases pressure, airs fills lung until pressure is the same as outside.
How does the process of forced exhalation differ from quiet ventilation?
Quiet ventilation
MM relax volume decreases = inc. intrapulmonary pressure
Forced exhalation
Abdominal and intercostal muscles contract decreasing the intrapulmonary volume by pulling down the ribs. = increase intrapulmonary pressure
What is lung compliance and what are its determinants?
Capacity of lungs to stretch and contract
What is airway resistance and what is it determined by?
resistance to airflow in respiratory passageways
What are the following respiratory volumes?
- Tidal
- Inspiratory reserve
- expiratory reserve
- residual
- Tidal - natural breathing
- Inspiratory reserve = deep inhale
- expiratory reserve = deep exhale
- residual = what is left after deep exhale
What are the following respiratory capacities?
- Inspiratory capacity
- Functional residual capacity
- vital capacity
- total lung capacity
- Inspiratory capacity = Inspiratory reserve plus tidal
- Functional residual capacity = Expiratory reserve plus residual
- vital capacity = Tidal+expiratory+inspiratory
- total lung capacity = all volumes
What is the difference between obstructive and restrictive ventilation disorder
Obstructive = restricted airflow (asthma) Ventilation = decrease ability of lungs to expand (cancer pregnancy, pneumonia)
Which respiratory volumes and capacities would be increased with an obstructive disorder?
Residual volume increase - air is trapped.
Which respiratory volumes and capacities would be reduced with a restrictive disorder?
Decrease in residual volume and inspiratory reserve volume
What is daltons law and how can it compare to alveolar air?
Total pressure is the sum of the individual pressures of the gas component.
Alveolar air is similar to atmospheric air during inhaling, so during exhale, the air expelled is diffused and the air would be a mixture of alveolar and atmospheric air.
What is Henry’s law and how does it affect the respiratory membrane?
In constant temperature, the amount of gas dissolved in a liquid is directly proportional to the partial pressure of the gas.
The pressure in alveoli is high and low in blood, so oxygen dissolves through diffusion into the blood which is a liquid through the respiratory membrane.
What is Fick’s law and how does it affect the rate of diffusion across a respiratory membrane?
Rate of diffusion across a membrane.
ROD = K x A x ((P1-P2)/D)
Factors affecting diffusion
1) constant diffusion = K
2) Area of exchange = A
3) Partial gas pressure = P
4) thickness of barrier = D
How is oxygen transported in the bloodstream?
1) Dissolved in plasma 1.5%
2) Bound to heam groups 98.5%
What 3 factors can affect oxygen saturation of haemoglobin and how?
1) local availability of O2
2) local presence of CO2
3) Increase in temperature = decrease in O2
How is CO2 transported in the bloodstream
1) Dissolved in CO2 plasma 7%
2) bound to haemoglobin 23%
3) Bicarbonate ions in plasma 70%
What are the neural controls of ventilation and how do they work?
Control centres that control respiration. They are located in the medulla and pons.
1) Medullary centre
- ventral respiratory group - pace + rhythm of breathing
- Dorsal respiratory group = rhythm of breathing
2) Pontine centre: smooth transition between inspiration and expiration
3) limbic system and hypothalamus: influence higher centre and emotions
4) cortex: conscious control of breathing
What is the difference between central and pheripheral chemoreceptors?
Central - can be desensitized with excess Co2
- Located at brainstem
- stimuli: Inc. Co2 + decrease PH
- Very sensitive
- Adaptable
Peripheral
- carotid body and aortic arch
- Stimuli decrease PH
- not sensitive
- not adaptable
