respiratory Flashcards
What is the function of goblet cells?
- Secrete mucous and traps particles less than 10microm
What forms the mucocilliary escalator?
- CILIA and GOBLET cells
Do particles less than 0.5 microm pass into the mucociliary escalator?
- NO!!
- Macrophages remove these particles
What are three ways that smoking leads to damage of the lungs?
- DESTROYS cilia lining the airways
- DAMAGES and DESTROYS walls between alveoli causing collapse
- Leads to CANCER in cells lining airways or in parenchyma (bulk of lung cells)
What is emphysema a result of?
- When alveolar walls are damaged–> collapse–> larger alveoli form–> bullae
- NOt good for gas exchange–> distance for diffusion too great–> hypoxia (decreased O2)
- Leads to gas trapping
- LUNGS GET BIGGER IN VOLUME BUT TAKE IN SMALLER AMOUNTS OF AIR
- INCREASED COMPLIANCE
What are two things that occur in bronchitis?
- thicker wals from inflammation
- Mucous buildup form DAMAGE to mucociliary escalators
- DECREASED FEV/FVC ratio
What does Boyle’s law state?
- Thorax is a closed containeer
- If there is incresed volume in a closed system, then pressure will decrease (air moves from low area–> high pressure)
What keeps the lungs inflated against the thoracic wall and the diaphragm?
- The NEGATIVE PRESSURE (atmospheric/barometric pressure)
Is the intrapleural pressure always negative?
- YES
- this holds the lungs to the chest cavity
When there is decreased INTRAPULMONARY pressure, will air move into or out of lungs? ** need to know how this changes during breathing!!
- INTO lungs
What are three factors affecting pulmonary ventialtion?
- Radius of airway
- Compliance of chest wall (affects the volume of air that can be inhaled/exhaled)
- Surface tension of alveoli (how easily alveoli will remain open to exchange gas)
What is TLC?
- total lung capacity –> can be measured with spirometer
What is TV?
- Tidal volume –> volume of breath normally at rest (e.g. 0.5L)
What is VC?
- Vital Capacity –> MAX amount of air you can EXHALE-INHALE
- Depends on how BIG you are and how AGE (this decreases with age)
- TOTAL volume of exchangeable air
What is IRV?
- Inspiratory Reserve Volume
What is ERV?
- Expiratory Reserve Volume
What is FRC?
- Functional Residual capacity
What is RV?
- Residual Volume
- Amount of air left in lung after FORCED EXHALATION –> Must be calculated not measured
What is minute ventilation and how is it calculated?
- the amount of air breathed PER MINUTE
MV= TV (tidal volume-mL) * BREATHING RATE (breaths/minute)
What is FEV1?
The forced expiratory volume in 1 second (i.e. in 1 second how much air that you breathed in can you breathe out? )
What is FVC?
- Forced Vital Capacity –> max amount of air that you can breathe out
What are examples of obstructive disorders?
- Asthma and COPD
- INCREASE in air flow –> DECREASED FEV1/FVC ratio (<75%)
What occurs in a restrictive disease?
- Lung or chest wall can’t inflate to normal capacity (lungs or ribs become LESS compliant) –> reduced FVC but can’t make a decision–> would do a TLC test-if less than normal –> restrictive disease
Which two factors of the spirometry graph is emphysema associated with?
- Increase in RV (residual volume) and increase in TLC
- Indicates gas trapping
Which 3 factors affect pulmonary ventilation?
- AIRWAY RADIUS (affects rate that air can enter and leave lungs)
- LUNG AND CHEST COMPLIANCE (How easy it is for air to get in and out of lungs affects volume of air)
- SURFACE TENSION OF ALVEOLI (determines how easily the alveoli are open for gas exchange)
The volume of air into or out of the alveoli is proportional to …
- The pressure difference between atm and alveoli
The volume of air flowing into or out of alveoli is INVERSELY PROPORTIONAL TO;
Resistance to flow of air in airways (highest in medium sized bronchioles) –> Poisuelles law
Which 4 ways is bronchomotor tone maintained?
- Vagal efferent nerves–> Ach released to cause bronchoconstirciton
- Sympathetic nerve supply –> NA released causes bronchodilation
- Circulating catecholamines–> e.g. A and NA interact with B2 receptors on smooth muscle –> bronchodilation
- Inhaled stimuli –> cigarettes, dust, cold air (reflex bronchoconstriction decreased resistance)
What are the two forces that determine lung compliacne?
- Elastic forces (1/3 lung)
2. Surface tension of air/water surface of alveoli (2/3 lung)
What happens to the alveoli when there is no surfactant?
- They collapse
- Can occur in babies when born –> can try to inject corrtisol to stimulate surfactant production
Which 3 things must the respiratory msucles overcome to INFLATE the lungs?
- RESISTANCE OF CHEST WALL
- RESISTANCE OF LUNG TISSUES
- RESISTANCE OF AIRWAYS
What are some diseases where the compliance is reduced?
- IN LUNG: FIbrosis–> lung tissue stiffened by scarr tissue –> thoracic cage expands normally but tissue compliace reduced and HARDER TO INFLATE
- More fibroblasts in intersitium= thicker area
- IN CHEST WALL: Scoliosis or polio/ muscle dystrophy (respiratory muscle weakness) –> stiff chest wall–> harder to inflate
What does a low compliane mean for the diaphragm and inspiratory muscles?
- Must contract MORE vigorously –> generate a greater sub-atm pleural pressure to expand lungs
What does spirometry look at for airway radius?
-FEV1
What does spirometry look at for lung and chest compliacne? -
- FVC
What is the spirometry test done before and after administration of ?
- Bronchodilator drugs
e. g. In asthma, after bronchdolator given (second test) it should show an INCREASE in FEV1