Respiration Mechanics Flashcards
what is tissue respiration?
the aerobic metabolism in cells
what is breathing?
gas exchange and the associated processes
what is respiration mechanics?
the study of mechanical properties of lung and chest wall and the process by which air enters and leaves the lungs
what is the lungs job?
to bring in fresh air rich in oxygen needed to fuel the body and to expel the waste (CO2) produced from cells in the body
why is respiratory mechanics important?
to understand how lungs work normally and in disease states, almost all lung disease affect mechanical properties of the lung and death from lung disease is usually due to the inability to overcome changes in lung and/or chest mechanics
what is the resting PO2?
100 +/- 2mmHg
what is the resting PCO2?
40 +/- 2mmHg
what is the exchange of O2 to CO2 at rest?
250ml O2/min and 200ml CO2/min
what is the exchange of O2 and CO2 when breathing regulation is continuous?
800ml O2/min and 750ml CO2/min
what is the exchange of CO2 and O2 when you are undertaking severe exercise?
5000ml O2/min and 6000ml CO2/min
what is the function of the nasal cavities and paranasal sinuses?
filter, warm, humidify air, detect smells
what is the function of the pharynx?
conducts air to larynx, a chamber shared with the digestive tract
what is the function of the larynx?
protects opening to trachea and contains vocal cords
what is the function of the bronchi and trachea?
filters air, traps, particles in mucus and has cartilages to keep airway open
what is the function of the lungs?
responsible for air movement through volume changes during movements of ribs and diaphragm; include airways and alveoli
what is the function of the alveoli?
act as sites of gas exchange between air and blood
what are the major functions of the upper airway?
humidify (saturate with water), warm (to body temp) and filter
what is the epithelium of the upper airways?
pseudo-stratified ciliated columnar epithelium
what is the ventilation at rest?
about 6L/min, about 12 breaths of 500ml
what is the max ventilation?
160L/min, about 40 breaths of 4L
what is the cardiac output at rest?
5L/min, 70bpm, 70ml/beat
what is the max cardiac output?
25L/min, 200bpm, 125ml/beat
what is inspiration when practising quiet breathing?
active
explain the mechanism of inspiration in quiet breathing
diaphragm contracts downwards pushing abdominal contents outwards, external intercostals pull ribs outwards and upwards
what is expiration when practising quiet breathing?
passive
explain the mechanism of expiration in quiet breathing
elastic recoil
what is inspiration when practising strenuous breathing?
active
explain the mechanism of inspiration when strenuous breathing
greater contraction of diaphragm (1cm quiet breathing up to 10cm during strenuous breathing) and external intercostals. Inspiratory accessory muscles e.g. sternocleidomastoid, alae nasi and genioglossus
what is expiration when practising strenuous breathing?
active
explain the mechanism of expiration in strenuous breathing
abdominal muscles used (rectus abdominus, internal oblique, external oblique and transversus abdominus), internal intercostal muscles oppose external intercostals by pushing ribs down and inwards
what is Pa?
alveolar pressure
why does the Pa = 0 at the beginning of inspiration?
because there is no flow
what is Ppl?
pleural pressure
what is Pel?
plastic recoil pressure
what is Pl?
transpulmonary pressure
what is Pb?
barometric pressure
in healthy lungs how efficient is low level breathing?
very efficient because there is a small muscle effort
in healthy lungs how efficient is higher intensity breathing and why?
less efficient because gas flow is more turbulent and it uses more muscles. The accessory muscles can fatigue easily to limit exercise
what is the functional residual capacitu?
the volume of air in the lung at the end of expiration during quiet breathing
what do the elastic recoil forces of the lung do?
act to decrease lung volume
what does the outward recoil of chest wall do?
acts to increase lung volume
at functional residual capacity what is the elastic recoil ad the outward recoil like?
opposite and equal and muscles are relaxed
what happens to the FRC when chest wall muscles are weak?
it decreases
what is FVC?
forces viral capacity
what is FEV?
forced expiratory volume in 1 second
in a healthy individual what is the FEV/FVC ratio and what does this mean?
it is greater than 70% meaning that 70% of the lung volume is expired in 1 second
in patients with obstructive lung disease what is the FEV/FVC ratio and what does this mean?
it is less than 70% meaning that less than 70% of the lung volume is expired in 1 second
in patients with restrictive lung disease e.g. pulmonary disease what is the FEV/FVC ratio?
greater then 70% because the lung volume (FVC) is smaller
