Week 2 Lung defense and respiratory Load Flashcards
What are the main functions of the URT?
- Conduction of gas to LRT
- Humidifies and warms air
- Filters air
Liquid or solid particles suspended in air.
Diameter of such particles is important for the lung.
Aerosol
How many micrometres (μm) of aerosol pose the greatest threat to the lung?
<10 μm
Medium particles (1-3μm) are deposited in the airways via?
Sedimentation
Particles > 5-10μm are filtered where in the URT?
At the nasopharynx and the tracheobronchial tree
Particles that reach the alveoli are cleared by?
Phagocytosis (alveolar macrophages, neutrophils, monocytes, digested or moved up airway to mucociliary escalator)
- closure of this part of the URT prevents aspiration of foreign material (food and liquid) into the LRT
Epiglottis
Layer of the respiratory mucous which contains the periciliary, a thin and fluid like, and allows the movement of cilia
Sol layer - deeper layer
What is the mucociliary clearance?
- helps or is responsible in clearing airways of secreted mucous and trapped substances.
a layer of the respiratory mucous which is thick, gelatinous, and traps particles
Gel layer - superficial layer
This is what you call the movement of the secretions and apparatus for moving for moving it is called?
Mucociliary escalator
What is the 3 layers of the conducting airways?
Inner
- mucosa and submucosa
- mucous membranes
Middle
- smooth muscle
Outer
- adventitia (connective tissue)
It is compromised of 95% water, 3% glycoprotein, 1% lipid, 1% mineral (inorganic, electrolytes), and also contains IgA
Respiratory mucous
Phase of a cough which is dependent on air inspired
Inspiration Phase
Hair like projections from pseudostratified columnar epithelial cells
- none of this in the Alveoli
Cilia - beats with a whipping action
What are the factors that affect Mucociliary clearance?
- Age (as you get older = reduced cilial beat frequency)
- Sleep - has a depressant effect
- Exercise - results in greater MCC
- Gravity (posture)
- chemical irritations (smoke, dehydration)
- drugs
- High FiO2
- hypoxia and hypercapnia
A congenital disorder affecting the MMC which impairs cilial activity due to absence of contractile elements. Is associated with reduced fertility.
Immotile cilia syndrome (primary cilial dyskinesia)
A disease that affects the MCC, which makes the mucous thick and sticky, it is also due to abnormal chloride transport - thus leading to dehydration of mucous airways.
Cystic Fibrosis
Some other diseases that affect MCC
- bronchiestasis
- asthma
- chronic bronchitis
- a reserve clearance mechanism after MCC - it is also a protective mechanism for respiratory
Cough
A phase of cough wherein the glottis closes, muscles contract against glottis, there is a rise in abdominal pressure
Compressive phase
This is when airway will be compressed towards the mouth from the EPP
Expiratory airflow in airways in increased.
Dynamic Compression
The phase of cough wherein, glottis suddenly opens, rapid pressure drops in URT
Expiratory phase
What is Equal Pressure Point (EPP)
- point in which pressure in alveoli and pleura are equal
Note: EPP moves closer to alveoli at lower lung volumes
Happens when dynamic compression occurs with little expiratory airflow
Dynamic airway collapse
Phase of cough when the muscles relax and pressure returns to normal
Relaxation phase
Gas liquid interactions - 0-60 cm/sec, not applicable to cough
Bubble
An effective cough depends on the following?
- good inspiratory volume
- enough expiratory force
- stable airways
- and thickness of secretions
Gas liquid interactions - 60-1000 cm/sec, effective moving plugs of sputum
Slug
Gas liquid interactions - 1000-2500 cm/sec, wave like movement of secretions along airway
Annular
Gas liquid interactions - 2500 cm/sec. Aerosol droplets formed - Cough
Misty
What is the amount of effort that the respiratory muscles have to exert during the respiratory cycle called?
Respiratory work/work of breathing
Note: Work = weight x vertical distance moved
- work is required for respiratory gasses to move in and out
Inspiratory in terms of work of breathing are which loads?
- mainly elastic and resistive loads that come into play
- Elastic - lung and chest wall (elasticity)
- Resistive - airways
Expiratory in terms of Work of Breathing is mainly which load?
- mainly resistive load - airflow resistance
A property of matter that causes it to return to its original size after being stretched or compressed?
Elasticity
Elastic forces of the lung and chest wall have to be overcome by the ________ _________ in order to move gas.
Respiratory Muscles
What is lung compliance?
- volume change per unit change in pressure
The elastic load in the chest wall/thorax tends to?
- spring outwards and is then pulled inwards by the lungs
- joints and ligaments contribute to its flexibility
Lung is less compliant at?
High lung volumes, because it is harder to keep expanding due to elastic recoil
Chest wall is less compliant at?
Low lung volumes, because it is harder to continue to compress
what are the two types of resistance of Resistive Load?
- Inertial resistance and Frictional Resistance
It is generated when an object with a given mass is accelerated into motion.
In the Respiratory system: It is generated by gas / lungs/ chest wall when they start moving
Inertial Resistance
What is Respiratory muscle dysfunction?
- the reduction in ability to meet load
The stretching and movement of the lungs and chest wall causes friction as tissues move against one over another. - 15-20% of Frictional resistance during quiet breathing
Pulmonary and chest wall resistance (Frictional Resistance)
What are factors that may increase Work of Breathing?
- Increased in Elastic and or resistive load
- reduced lung compliance
- reduced chest wall compliance
- increased airway resistance
- increased tissue resistance
Represents 80% of total frictional resistance during resting breathing
Raw - Airway resistance
What is the metabolic consumption of O2 consumption by the respiratory rate at rest?
1-2% - really low cost and is efficient
Happens when there is an increasing static lung volume (FRC, RV)
- Starts as a compensatory mechanism to overcame increase Raw, however it leads to alterations in mechanics
Hyperinflation
What is the pressure necessary for tidal breathing?
-3 cmH2O
A term used to characterise a subjective term of breathing discomfort that consist of qualitatively distinct sensations that vary in intensity.
Symptoms of this can only be described by the person experiencing it.
Dyspnoea AKA Shortness of breath
