Vent+Gas exchange Flashcards
How would you describe these lungs?
Normothermic ex-vivo ventilated perfused lungs
def Alveolar ventilation (Valv)
The volume of air reaching the respiratory zone per minute
def Respiration
The process of generating ATP either with an excess of oxygen (aerobic) and a shortfall (anaerobic)
Physiological dead space
Equivalent to the sum of alveolar and anatomical dead space
def Hypoventilation
Deficient ventilation of the lungs; unable to meet metabolic demand (increased PO2 – acidosis)
def Hyperventilation
Excessive ventilation of the lungs atop of metabolic demand (results in reduced PCO2 - alkalosis)
def Hyperpnoea
Increased depth of breathing (to meet metabolic demand)
def Apnoea
Cessation of breathing
def Dyspnoea
Difficulty breathing
def Bradypnoea
Slow breathing rate
def Orthopnoea
Positional difficulty in breathing (when lying down)
Left>Right
Inspiratory reserve volume
Expiratory reserve volume
Tidal volume
Residual volume
Inspiratory capacity
Functional residual capacity
Vital capacity
How do you calculate functional residual capacity?
Expiratory reserve volume + Residual volume
How do you calculate vital capacity?
Expiratory reserve volume + Tidal volume + Inspiratory reserve volume
How do you calculate Inspiratory capacity?
Tidal volume + Inspiratory reserve volume
How do you calculate minute ventilation?
Breathing frequency * Tidal volume
How do you calculate alveolar ventilation(Gas entering and leaving the alveoli)?
(Tidal volume - Dead space) * Breathing frequency
What factors affect lung volumes and capacities?
Body size
Sex
Disease
Age
Fitness
def Physiological dead space
Anatomical + Alveolar dead space
16
150mL
Anatomical dead space
No blood supply
0mL
Alveolar dead space
7
alveolar ventilation
Spring outwards
Recoil inwards
What constitutes the neutral position of the chest
Equilibrium forces of the chest wall and the lung
What muscular impact causes inspiration?
What muscular impact causes expiration?
What pressure change occurs in negative pressure breathing?
What pressure change occurs in positive pressure breathing?
What is the function of the internal and external intercostal msucles?
Internal: Pull ribcage down and in
External: Pull ribcage up and out
What does Daltons’ law describe?
What does Ficks’ law describe?
What does Henrys’ law describe?
What does Boyles’ law describe?
What does Charles’ law describe?
How does air composition change per altitude?
Composition remains the same, only volume changes
What happens to air as it passes down the respiratory tree?
WARMED, HUMIDIFIED, SLOWED and MIXED
Describe the structure of Haemoglobin
Haemoglobin monomers consist of a ferrous iron ion (Fe2+; haem- ) at the centre of a tetrapyyrole porphyrin ring connected to a protein chain (-globin); covalently bonded at the proximal histamine residue
At what point in the respiratory tree does CO2 and H2O become present?
CO2 - Respiratory airways
H2O - Conducting airways
How is Haemoglobin an allosteric protein?
2,3-DPG binds to allosteric site on Hb, decreasing Hbs’ affinity for O2
What causes a left shift on the Hb O2 dissociation curve?
What causes a right shift on the Hb O2 dissociation curve?
What causes an upwards shift on the Hb O2 dissociation curve?
What causes a downwards shift on the Hb O2 dissociation curve?
What causes a downwards and leftwards shift on the Hb O2 dissociation curve?
Where would the curves for foetal Hb and myoglobin be on this graph and why?
What are the 3 ways CO2 is generally transported in the blood?
In solution(Plasma)
Bicarbonate (HCO3-)
Carbamino compounds (e.g. HbCO2)
What are the 3 ways CO2 is loaded into tissues and which is fastest and why?
- CO2 stays in solution in plasma
- CO2 binds to amine end of globin chains
- CO2 is enzymaticaly converted to bicarbonate and moved back to plasma(fastest due to enzyme action)
