Respiratory phys I & II Flashcards
Respiratory functions / regulated processes
- External respiration
- pulmonary ventilation /breathing
- gas exchange in pulmonary capillaries of the lungs - Transport of gases by blood
- Internal respiration
- systemic tissue gas exchange
- cellular respiration - Overall regulation of respiration
Pulmonary ventilation/breathing
- Inhalation / inspiration
- moves air into the lungs - Expiration / exhalation
- moves air out of the lungs
*air flows form high pressure to low pressure
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Mechanisms of pulmonary ventilation
- pressure gradients are established by changes in the size of the thoracic cavity
- produced buy contraction and relaxation of respiratory mm
- boyle’s Law is important for understanding the pressure changes that occur in the lungs and the oral during the breathing cycle
Boyle’s law
The pressure of a gas in a closed container is inversely proportional to the volume of the container
Inspiration
Expansion of the thorax - decreased alveolar pressure - air flows in to lungs
- expansion of the thorax results in decreased alveolar pressure
- air moves into the lungs when alveolar pressure drops below atmospheric pressure
- atmospheric = 760 mmHg
- alveolar = 758 mmHg
Inspiration
- contraction of the diaphragm
- quiet respiration: diaphragm descends about 1 cm producing pressure difference of 1-3 mmHg
- strenuous breathing: diaphragm can descend up to 10 cm producing a pressure difference of 100 mmHg
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Quiet expiration
- a passive process that begins when inspriatory mm are relaxed, decreasing the size of the the thorax
- no active mm involvement
Expiration
- decreasing thoracic volume increases alveolar pressure above atmoshpheric pressure and air moves out of lungs
- air moves out of the lungs when alveolar pressure exceeds atmospheric pressure
- atmospheric = 760mmHg
- alveolar = 761mmHg
Elastic recoil
Tendency of pulmonary tissuese to return to a smaller size after having been stretched during inspiration
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Compliance
How much effort is required to stretch the lungs and chest wall
- high = lungs and chest wall expand easily
- low = lungs and chest wall resist expansion
- factors include elasticity and surface tension
Airway resistance
- Normal inspiration
- bronchioles enlarge because their walls are pulled outward in all directions
- decreased resistance - Normal exhalation
- bronchioles return to resting diameter with elastic recoil of lungs
- increased resistance
Inspiration mm
- Diaphragm
- External intercostals
- Muscles that aid in forced inspiration:
- scalenes - SCM - trapezius - pec min - pec major
Forced exhalation mm
- Internal intercostals
- rectus abdominis - external oblique - internal oblique - transverse abdominis
Pulmonary volumes
The amounts of air moved in and out of the lungs and remaining in them are important to the normal exchange of O2 and CO2
Spirometer
Instrument used to measure volume of air exchanged in breathing
Tidal volume
Amount of air inhaled and exhaled in normal breathing
Inspriatory reserve volume
When you take a deep breath, more than 500mL of air is inhaled
- this additional air is the inspriatory resever volume
Expiratory reserve volume
Amoun of air that can be exhaled after normal exhalation (approx. 1200 mL in men and 700mL in women)
Residual volume
Amount of air that cannot be forcible exhaled
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Pulmonary capacities
Measuring lung capacities helps monitor the response of treatment and progression of respiratory disease
- lung capacity dependent on the lungs ability to get air in = inspiration
- things that affect lung volumes:
1. Chest wall deformities (scoliosis, kyphosis)
2. Neuromuscular disorders (Lou Gehrig’s, quadriplegia)
3. Pleural disease (fluid in pleural space)