Respiratory system: Mechanism Flashcards
Lung volumes and capacities:


Restrictive lung disease
difficulties with filling lung with air
“hugging bear disease”
Obstructive lung disease
Difficulties with exhaling air
(like hand in front of mouth)
Dead space (different types + volumes)
Physiological dead space: air that does not participate in gas exchange
Split into
- anatomical dead space = air conducting system, normally 150ml
- alveolar dead space= alveoli wihout blood supply –> normally 0ml
Boyles Law
Gas can be compressed (volume is determined by pressure)

Chest wall- Lung relationship
Are attached to each other via Pleura
Normally: chest would be bigger, lung would be smaller but form equilibrium in middle
–> this allows minimal changes around neutral pressure to have bigger effects on lung volume

The three compartment model
Three compartments with different pressures:
- Atmospheric (Patm)
- Interpleural pressure (P Ip/Pi) )
- Inraalvelolar pressure (Palv)
Three Pressure Gradients can be calculated:
- Transpulmonary pressure (PTp= PPi - PAlv)
- Transthoracic pressure (PTT= Ppl- Patm)
- Transrespiratory system pressure (PRS=PAtm - PAlv)
—> most importatn: drives inspiration+ expiration

Pulmonary function test: Protocol for Volume time curve
Protocol
- Patient wears noseclip
- Patient inhales to TLC
- Patient wraps lips around mouthpiece
- Patient exhales as hard and fast as possible
- Exhalation continues until RV is reached or six seconds have passed
- Visually inspect performance and volume time curve and repeat if necessary. Look out for:
- a)Slow starts
- b)Early stops
- c)Intramanouevervariabiltiy
Explain volume-time curves, important measurements and effect of obstructive /restrictive lung disease on it
FVC= forced vital capacity
FEV1 = Forced expiration volume after one minute
–> Measures airway resistance and FVC

Peak flow
Measures peak flow (l/min)
Measures Airway resistance (how fast can be exhaled?)
The peak flow meter can measure it.
–> Normal ranges for sex, age, and height

Compare alveolar vs pulmonary ventilation
Pulmonary ventilation:
gas that is taken into the lungs in one breath
Alveolar ventilation:
air that reaches the alveoli (Tidal volume - dead space)
Classification of Lung disease

Control of airway function (Neurological pathway, hormonal way)
Parasympathetic innervation: contraction via Vagus nerve
Vasodilation (more blood supply to tissue)
Sympathetic: Dilation (via doral route ganglion and adrenaline)
BUT also NO synthesis (only species, causing relaxation)

Changes in Cells in Ashmah
- overresponsiveness to stimuli causes airway obstruction
- Airway inflammation –> remodeling
- More mucus production (Hypertrophy/Hyperplasia of mucous glands)
- Airway constriction (SM hypertrophy/Hyperplasia)
- New vessels formation
–> positive feedback: inföammatory agents feedbak on rest
Daltons Law
the pressure of gas mixture = sum of the pressure of all partial pressures of the gases in it
P(gas mixture) = ∑P(gas 1) + P(Gas 2) ………P(<strong>Gasn</strong><strong>)</strong>
Ficks law
diffusion of a gas across a membrane is determined by
- a concentration gradient (p1-P2)
- and surface area(A)
- the thickness of the surface(T)
- and diffusion capacity of gas (D)
“V Gas”= 𝑨/𝑻∙𝑫∙[𝑷_𝟏−𝑷_𝟐]
Hernry’s law
solubility
is determined by Pressure (P) of gas and individual solubility
𝑪_( 𝑫 𝑮𝒂𝒔)=𝒂_( 𝑮𝒂𝒔) ∙ 𝑷_( 𝑮𝒂𝒔)
Boyle’s law
At constant temperature, the volume of a gas is inversely proportional to the pressure of a gas
P_(Gas)∝ 1/V_(Gas)
Charle’s law
At constant pressure, the volume of a gas is proportional to the temperature of a gas
𝑽_( 𝑮𝒂𝒔)∝ 𝑻_( 𝑮𝒂𝒔)
Differentiate between different form of Haemoglobin
1.“Normal” Haemoglobin (HbA) : Two alpha, two beta chains
When 4 O2 bind–> 5th binding site for 2,3-DPG appears (Allosteric –> effect on another binding site than ligand, regulatory function) –> when binding this “pushes” oxygen out
2. HbA2: two alpha, two delta chains
found in thalassemia
2. Fetal Haemoglbin (HBF): Two alpha, two gamma chains
– steals o2 from maternal haemoglobin –< higher affinity
3. Meta Haemoglobin (MetHb):
does not bind oxygen (F3+ already in middle) –< can convert into HbA (constant changing between two forms) by MetHb reductase
Cooperative binding
First O2 in haemoglobin in difficult to bind, following get easier
Myoglobin
haemoglobin in muscle –> stores 02 and extracts it from blood –> higher affinity for O2
When does a Sidewards shifts in the Oxygen dissociation curve occur?
Right shift (increased pressure required to get same saturation)
- increase in temperature
- acidosis
- hypercapnia
- increase 2,3, DPG
Left shift (less pressure required for same saturation
- decreased temperature
- alkalosis
- hypocapnia
- decreased 2,3, DPG

Up and downwards shifts in oxygen dissociation curves
Down: Anaemia: 100% saturated but not enough Hb available
UP: Too much Haemoglobin (e.g. doping, altitude), greater capacity of Hb to bind O2




















