The Respiratory System Flashcards
what are the zones of the respiratory system?
the conducting zone
the respiratory zone (gas exchange)
how does ventilation occur?
decrease lung pressure- increase lung volume- air in
increase air pressure- decrease lung volume - air out
what is boyles law?
the pressure of a quantity of gas is inversely proportional to its volume
P = 1/V
what are the pleural membranes?
the parietal and visceral (outer)
what is intrapleural pressure?
pleural membranes pulled in opposite directions - always lower than intra-alveolar pressure
keeps lungs adhered to thoracic cavity
what is a pneumothorax?
collapsed lung
what does alveoli fluid and air in alveoli generate?
surface tension
what is the role of surfactant?
disrupts cohesive forces between water molecules and breaks surface tension
what causes respiratory distress syndrome?
premature infants born without surfactant- difficulty in expanding lung volume
what is surfactant composed of and where is it produced?
composed of lipoprotein complexes
produced by type II alveolar cells late in foetal development
what triggers bronchodilation?
noradrenaline - sympathetic
what triggers bronchoconstriction?
acetylcholine - parasympathetic
how is asthma treated?
stimulation of B adrenergic receptors with adrenaline or P agonists triggers bronchodilation
what is the pulmonary function test?
spirometry
what is tidal volume?
vol of air inspired or expired during regular breathing
what is the minute volume?
ventilation rate x tidal volume
what is vital capacity?
tidal vol + ERV + IRV
What is total lung capacity?
vital capacity + residual volume
what does asthma affect?
rates of expiration and inspiration
how are obstructive lung disorders diagnosed?
one second forced expiratory volume which measures percentage of vital capacity exhaled in 1 second
what is partial pressure?
individual pressure of each gas
atm pressure x % of gas in atmosphere
what does the ability of gas to dissolve in blood depend on?
ie Henrys Law
- pressure gradient
- solubility of gas
- temp of blood
what is the diffusion of gases in the alveoli due to?
pressure gradient
what causes decreased diffusion of oxygen?
emphysema and pulmonary oedema
how is o2 transported in the blood?
dissolved in plasma and mostly bound to Hb
what effects haemoglobin affinity to bind O2?
Po2 of plasma and total Hb levels
what effects O2 affinity to Hb?
- blood pH
- blood temp
- metabolic activity
how is CO2 transported?
- plasma
- Hb
- mostly converted to Bicarbonate in RBCs
what enzyme converts CO2 to bicarbonate?
carbonic anhydrase
