Resp 1 Flashcards
Pulmonary ventilation
Moving air into and out of the lungs
External respiration
Gas exchange b/w the lungs and the blood
Transport
Transport of oxygen and carbon dioxide b/w the lungs and tissues
Internal respiration
Gas exchange b/w the systemic blood vessels and tissues
Fx
Fractional volume or pressure (FN2 nitrogen fraction of pressure)
Cx
Concentration (content)
CO2: total oxygen content
a
Arterial blood
A
Alveolar gas
c
Pulmonary capillary blood
E
Mixed expired gas
Do not take part in gas exchange “physiological shunt”
Bronchial arteries
From aorta, bronchial arteries are __ % of cardiac output
2
Bring deoxygenated blood from right ventricle
Pulmonary arteries
Functions of nose:
Heat & moisture exchanger (HME) Air conditioning (100% humidification & warming the inspired air) Filtration by nasal hairs (up to 6 micrometer particles)
Bleeding can occur while inserting nasal tubes d/t?
Increased vascularity of nasal mucosa
_________ can lead to lung crusting and infection
Tracheostomy
Which lung is more common site for inhaled foreign object? Why?
Right; Right main stem bronchus is more wide and vertical
________ pleura covers lung, ______ covers chest cavity
Visceral; parietal
What is the pressure in the pleural space? Why?
-5 cmH2O. Lungs have natural tendency to collapse while ribs try to move outward creating a vacuum in the pleural space
What happens to the pressure in the pleural space if air is introduced such as a stab wound or pneumo?
Will become 0 cmH2O (lung will collapse)
What happens if elastic tissue is destroyed?
The inward force is less and the chest cavity starts moving outward (Barrel shaped chest deformity)
Right main stem bronchus makes a _____ degree angle while left makes a _____ degree angle with trachea
25; 45
________ cells secrete mucus
Goblet
Clear the passageways “house keepers”
Cilia
Type II cells
Produce surfactant
Type I cells
Produce angiotensin converting enzyme
Total surface are of resp membrane
70 m2
Resp membrane consists of:
Alveolar fluid lining (contain surfactant) Alveolar Epithelium Epithelial basement membrane Interstitial Space Capillary basement membrane Capillary endothelial membrane
DLCO
Diffusion capacity of lung for Carbonmonoxide
Reduced DLCO indicates?
Disrupted alveolar capillary surface
Abnormal in emphysema & interstitial fibrosis
Most important muscle for inspiration
Diaphragm
Muscles used for inspiration during exercise and respiratory distress
External intercostals, scalene, & sternomastoids
Inspiration is active or passive process?
Active
Expiration is active or passive process?
Passive (no ATP)
Expiratory muscles used with exercise or with airway resistance (asthma)
Rectus abdominis, internal & external oblique, transversus abdominis, internal intercostal
What happens when the diaphragm contracts/descends?
It increases intrathoracic volume & decreases intrathoracic pressure below atm pressure allowing air to enter lungs down its pressure gradient
The diaphragm accounts for ______ of tidal volume during normal quiet respiration
75%
Diaphragm supplied by which nerve?
Phrenic (C3-C5)
If the tidal volume is 500 ml, how much is an atomic dead space?
150 ml (2ml/kg)
Factors that increase dead space
Pulmonary vascular disease, pulmonary embolism, COPD, ARDS, Pulmonary fibrosis, shock, old age, positive pressure ventilation
Factors that decrease dead space
Artificial airways (d/t narrow diameter)
The volume of air that enters non-perfused or poorly perfused alveoli. Normally 0
Alveolar dead space
Physiological dead space (VD) =
Tidal volume x (PaCO2 - PECO2)/ PaCO2
Minute ventilation
Sum of all exhaled gas volume in 1 min
Tidal volume x breaths/min = 5L/min
Alveolar ventilation
Volume of inspired gases actually taking part in gas exchange in 1 min
Indicated by PCO2
= (tidal volume - dead space) x breaths/min
Normal air pressure in alveoli
0 cmH20
Air pressure in alveoli _______ in inspiration and _______ in expiration
Decreases; increases
The major driving force for air flow into the lungs during quiet normal inspiration
The air pressure in alveoli
Transpulmonary pressure =
Alveolar pressure - pleural pressure
First breath of neonates generates transpulmonary pressure of?
40-80 cmH20
During inspiration, pleural pressure goes from ____ to ____ cmH2O
-5 to -8
Why does forced expiration (COPD) cause airway collapse?
The intrapleural pressure becomes more positive compressing the airways (Bernoulli’s law)
Shows distensibility of lungs and chest wall
Lung compliance
Lung compliance is ______ related to elastance, which depends on the amount of elastic tissue; _____ related to stiffness
Inversely; inversely
Compliance =
Change in volume of lung/ change in transpulmonary pressure. 200 ml/cmH20
With emphysema the lung-chest wall system will seek a new _____ FRC while with fibrosis it will seek a new ____ FRC
Higher; lower
