module 1 Flashcards
(287 cards)
work of breathing
amount of effort required for maintenance
signs of difficulty breathing
tripod positioning, accessory muscle use
what happens with increased work of breathing?
- increased energy expenditure and body uses more glucose
compliance
elasticity and expandability of the lungs and thoracic structures
ventilation
- diffusion at pulmonary capillaries
- perfusion
- diffusion to cells
inspiration
- active
- diaphragm lowers and contracts
- intercostal muscles contract
- thoracic cavity expands
- intrapleural and intra-alveolar pressures become negative = air flows into lungs
expiration
- passive
- diaphragm relaxes
- intercostal muscles relax
- thoracic cavity reduces
- lungs recoiling generates positive intra-alveolar pressure w. air flowing out of lungs
O2 in the blood vs alveoli
- O2 in blood within capillaries of lungs is lower than in the alveoli; O2 diffuses from the alveoli to the blood
CO2 concentration in blood vs alveoli
- CO2 has higher concentration in blood than in alveoli - CO2 diffuses from the blood into the alveoli
transportation of oxygenated blood
- oxygenated blood in pulmonary capillaries is transported via the pulmonary vein to the left side of the heart
- it is then perfused and transported to tissues
transportation of CO2
- transported via the vena cava to the right side of the heart and into pulmonary capillaries
- diffuses into alveoli and is eliminated through expiration
what do the pons and medulla control?
rate, depth, and rhythm of ventilation
what stimulates respirations (increases rate/depth to blow it out)
hypoxia or increased partial pressure of CO2
what diminishes respirations
too much ventilation, decreased partial pressure of CO2
factors that determine compliance
- surface tension of alveoli, connective tissue and water content of lungs + compliance of the thoracic cavity
increased compliance
lungs have lost their elastic recoil and become over-distended = emphysema
- more distended lungs requires lower pressures during ventilation; can collapse during expiration
decreased compliance
lungs and thorax are stiff
causes = morbid obesity, pneumothorax, hemothorax, pleural effusion, pulmonary edema, atelectasis, pulmonary fibrosis, + ARDS
- requires greater-than-normal energy expenditure to create negative pressure to inflate lungs
resistance
- opposition to flow of gasses in the airways
reasons for resistance
- Contraction of bronchial smooth muscle (asthma)
- thickening of bronchial mucosa (chronic bronchitis)
- obstruction of the airway by mucus, a tumor, or foreign body
- loss of lung elasticity
tidal volume (symbol, normal value, significance)
- VT or TV
- 500 mL
- may not vary, even with severe disease
tidal volume description
volume of air inhaled and exhaled with each breath
inspiratory reserve volume (symbol, normal value)
- IRV
- 3000 mL
inspiratory reserve volume description
maximum volume of air that can be inhaled after a normal inhalation
expiratory reserve volume (symbol, normal value, significance)
- ERV
- 1100 mL
- decreased with restrictive conditions (obesity, ascites, pregnancy)