respiratory strand test questions Flashcards
what is the role of surfactant
surfactant is a phospholipid which decreases the surface tension in alveolar cells
do the lungs act as a reservoir of blood
yes
how do lungs stop blood clots entering systemic circulation
filter them out
which metabolites play an important role in defence agains inflammation and homestasis
synthesis of a arachidonic acid metabolites such as eicosanoids
what is acute bronchitis
usually self limiting which is acute inflammation of the trachea and bronchi
what is pleurisy
inflammation of the pleura
what is pulmonary fibrosis
inflammation of the airways producing lung scarring and cyst formation
what are the energy uses in breathing
about half is dissipated during inspiration as heat to overcome resistance to airflow
the rest is stored as potential energy in elastic structures of the lung which drives normal expiration
what do flow volume loops measure
velocity of air flowing through the airways in relation to the volume of air moved during inspiration and expiration
how does the rib cage aid inspiration
increase diameter of the chest making the negative pressure in the lungs more negative
how do the joints in the ribs aid inspiration
joints between posterior ends of the ribs and the transverse vertebrae enable the lower ribs to swivel upwards and outwards
aids 25%
diaphrgam 75%
what specifically are restrictive lung diseases
reduced total lung capacity but airflow and airway resistance is normal
what are examples of intrinsic lung diseases
restrictive
lung tissue is destroyed which reduces lung volume
air spaces may be filled with inflammatory exudates
chronic inflammation or scarring
what are examples of extrinsic lung disorders
affect the muscles of respiration which impair movement
what are some examples of restrictive lung disease
pneumothorax
pulmonary embolism
ARDS
pulmonary fibrosis
what do the external intercostals do
move ribcage upwards and outwards to increase lateral and anterograde-posterior diameter of the thorax
how do the neck muscles aid in respiration with examples
pull rib cage up
sternocleidomastoids elevate the sternum
scalenus major elevate the first two ribs and the sternum
how do abdominal muscles aid respiration
the oblique, transverses and rectus abdomens pull the ribcage downwards
which muscles fix the shoulder girdle in respiration
pec major
lat dorsi
pull ribcage outwards
what does the position of the diaphragm
posture
how does being the upright posture affect the diaphragm
sinks and flattens out under gravity therefore movement required to reach expansion is smaller
how does effort of breathing change while in supine position
diaphragm is more dome shaped so more effort required on inspiration
describe the nervous supply to the diaphragm and the intercostal muscles
phrenic from c3-5 left and right
branches peripherally to the intercostal muscles
how much does the diaphragm move in eupnoea and heavy breathing
1.5cm to 7 cm
what would spinal injuries above C3/4 result in
apnoea and death
how does vaporisation of liquids contribute to total pressure
pressure of water vapour is independent of barometric pressure but dependant on temperature
therefore partial pressure of gas in humidified air must be reduced so that the total will be equal to barometric pressure
when you ventilate how does the intrapulmonary pressure change
falls and rise about 3 mmHg below and above atmospheric pressure
why is the intrapleural pressure usually sub atmospheric
elastic recoil of the lungs trying to separate the two layers
what happens to intrapleural pressures during deep inspiration
pressure drops 40 mmHg below atmospheric
what is used to measure intrapleural pressure
manometer
what is atelectasis and what is it caused by
failure of the lungs to expand
acutely by foreign bodies
chronically by tumour
what happens to the lungs and alveoli in atelectasis
collapse of lung and alveoli
what causes compression in atelectasis
pleural effusion or pneumothorax opposing inflation
what is bronchiectasis
permanently dilated bronchi with chronic infection
flow related collapse is common in which diseases
asthma and emphysema
airway collapse over time can lead to what
hyperinflation of the chest as air gets trapped
what is the closing capacity of the lungs
The closing capacity (CC) is the volume in the lungs at which its smallest airways, the respiratory bronchioles, collapse
what happens when closing capacity exceed FRC
compromise gas exchange
what happens to lung compliance in pulmonary fibrosis
reduces as the lungs become less elastic
how is compliance in a new born different and old age
low compliance so lungs are not easy to inflate
decreases in old age
which diseases cause decrease in lung compliance
emphysema
pulmonary fibrosis
pulmonary congestion
what is lung capacity
the amount of gas that an be accommodated will depend on the size of the lungs and the thorax related to age, sex and ethnicity
what is lung volume
the amount of gas that can be moved with respiration and depends on inspiratory and expiratory effort
what is a typical breathing rate at rest
12 - 15 breaths per minute
what is the average tidal volume
500 ml
who have larger FEV1 and FVC
swimmers divers and brass players
how could you measure airway obstruction
FEV1/FVC or FEV1 expressed as a percentage of FVC
at what age does FEV1 usually start to decline
30 but it is accelerated in COPD
which drugs can be used to decrease the rate of FEV1 normally and in COPD
no drug has yet been shown
how can you distinguish between COPD and asthma
measure FEV1 and PEFR after use of a b adrenreceptor agonist such as salbuatamol
asthma should be reversed
what is the max improvement in FEV1 or PEFR after use of salbutamol
no greater than 15% or max 200 ml/s
what type of flow increases resistance
turbulent flow
what happens if workload to breathing becomes too much
respiratory fatigue
what by definition is airway resistance
result of frictional forces opposing the flow of air
airflow in the centre of tubes in analogous to what
blood
which equations describes the resistance of laminar flow of air
poiseullies law which indicates that resistance increases to the power of 4 as the airways narrow
what usually creates the most resistance to airflow in the lung
large airways, trachea and bronchi larger than 2 mm diameter
this is due to having a much smaller cross sectional area
what can increase resistance to airflow outside of the conducting airways
tumour
mediastinal masses
hilar lymph nodes
during anaesthetics what happens which can cause increased resistance to airflow
tongue falls back and causes block
what objects outside the body can cause airway resistance
aspirated objects such as peanuts or pretzels
inflammation in asthma can lead to what
oedema and mucus plugging
during asthma what cells enter the airways and cause damage
eosinophils and lymphocytes
which three things must you consider when determining treatment for lung obstruction
bronchospasm
inflammation
secretion
what are mast cells activated during allergy
attachment of Fc portion of immunoglobulin IgE and other complement factors
what happens when mast cells become activated by IgE
rise in intracellular Ca and release of chemical mediators - mainly histamine which is stored inside granules
activation of mast cells leads to the synthesis of what
arachidonic acid derivatives such as leukotriene C4 that cause a slow but sustained contraction of bronchial smooth muscle
during inspiration there is a small change in pressure until pressure reaches what amount
at 5-6 mmHg inflation becomes much faster and volume is changed rapidly
what shape of inflation is there during inspiration and until what mmHg
non linear expansion until past 5-6 mmHg then reaches max around 15 mmHg
what happens to the graph of expiration during deflation
the curve is displaced to the left so that the pressure at any volume is less on expiration than inspiration
what is hysteresis
the presence of surfactant allows easier expiration and lower pressure than that of inspiration
Lung hysteresis is evident when observing the compliance of a lung on inspiration versus expiration. … Lung volume at any given pressure during inhalation is less than the lung volume at any given pressure during exhalation.
check diagram on homepage
what do the elastic properties of the lungs mean for intrapleural pressure
tend to pull them away from the elastic wall giving rise to negative intrapleural pressure
what happens to intrapleural pressure when you inhale
intrapleural pressure becomes from negative
rate of simple diffusion is dependant on what
pulmonary diffusing capacity
thickness of the membrane (0.5 - 0.2) microns
gas concentration gradient in solution
what is the law of diffusion across the membrane
Ficks law
what test is more usually a test of pulmonary diffusing capacity
the single breath CO diffusion test
what is the average oxygen diffusing capacity
15 - 35
around 20 ml/min/mmHg
what affects the oxygen diffusing capacity
exercise increases it due to dilation of capillaries and opening of closed capillaries in the apex of the lung
it is decreased due to thickening of the membrane such as in scleroderma, pulmonary fibrosis, asbestosis
also decreased due to reduction of area such as in emphysema
what does the concept of partial pressures apply to
both gases and liquids
when does a gas enter a liquid
gas molecules enter a liquid until the partial pressure in the liquid matches that of the surrounding air - even between air and liquid
the rate at which a gas equilibrates in a liquid depends on what
the gas solubility and on chemical binding in the liquid
what happens if there is CO2 retention in the alveoli
less O2 enters the blood
which lung volume cannot be measured by spirometry
residual volume or any volumes left in the lung after a full exhale
during expiration which pressure is greatest
expiration the PA (pressure in the alveoli) is greater than PB (pressure in the atmosphere)
how is turbulence created and what is the difference in sound to laminar flow
laminar flow is silent
turbulent flow is noisy
turbulence results from high air flow and common near the edges of airways
beyond which zone in the lung is there no cartilage and therefore rely on elastic recoil to prevent collapse
generation 11
which diseases are common to have flow related collapse
emphysema and asthma
what happens to FEV1 in obstructive disease
decreased
what happens during alveolar fibrosis
there is increased thickness of the alveoli membrane
what is alveolar consolidation
result of replacement of air with transudate, pus, blood or other cells
what are adenoids
small bumps as the back of the nasal passage above the mouth - glands that produce antibodies or white blood cells
which cells are present under cilia in the trachea lining
columnar epithelium
with pericillary layer and mucus layer on top
what is the difference between adult and foetal Hb
adult = 2 alpha and 2 beta
foetal has 2 alpha and 2 gamma
describe the 4 structures of Hb levels
primary - 141 ish amino acids per chain
secondary - globular structure
tertiary crevice for haemolytic and O2 binding
quaternary 4 chains
describe how these factors affect the O2 dissociation curve increase temp increase 2-3DPG increase CO2 increased pH increase CO
moves to right moves to right moves to right moves to left down
during gases exchange what is the kPa range of PaO2 and PaCO2 in oxygenated red blood cells
PaO2 - 10-13 kPa
PaCO2 - 4.5 - 6 kPa
what is the difference in alveolar pressure, PA, pulmonary arterial pressure Pa and Pulmonary venous pressure Pv in each of the zones of the lungs
zone 1: blood flow collapses PA > Pa > Pv
zone 2: Pa increases with respect to PA - vascular waterfall
Pa > PA > Pv
zone 3: blood flow depends on Pa and Pv
Pa > Pv > PA
what are the two factors that effect ventilation perfusion mismatch
dead space near apex where there is not blood flow due to collapse and no gas exchange but high ventilation
shunt vessels - hypoxia - no ventilation but good perfusion of blood
what is the difference in peripheral vs central chemoreception
peripheral - O2 decrease, CO2 increase, H+ increase
central - increase in CO2 and increase in H+
what are the steps of the oxygen cascade
dry air humidified air alveolar gas pulmonary capillary arterial blood mean capillary bed cytoplasm mitochondria
what are the responses of high altitude
hyperventilation
cerebral oedema
pulmonary oedema
alkalosis
what do these drugs molecules have on bronchi muscarinic antagonists ACh cAMP Adrenaline Adenosine Theophylline
Theophylline – reduces bronchoconstriction by stopping PDE converting cAMP to AMP as cAMP causes bronchodilation
Muscarinic antagonists – reduce bronchoconstriction
Beta agonists – increases cAMP causing bronchodilation
ACH – increases bronchoconstriction
Adenosine – increases bronchoconstriction
Adrenaline – increases bronchodilation
what are treatments for allergy induced asthma
mast cell stabilisation glucocorticoids desensitisation to allergens leukotriene antagonists B2 agonists
