Studied by 6 peopleList the three stages of respiration.
Ventilation→ mechanical
Gas Exchange→ diffusion of O2 and CO2
Cellular respiration→ utilization of O2
Name the respiratory zones.
Conducting zone
respiratory zone
List in order the sites of the conducting zone.
mouth
pharynx
larynx
trachea
primary bronchi
What is the function of the conducting zone?
1)raises temp
2)moistens air
Distinguish between terminal and respiratory bronchiole.
Respiratory bronchiole branch out from terminal bronchiole.
What blood vessels are found on the alveoli?
capilaries
How does air move?
From high pressure area to low pressure areas
What is breathing in called?
Inspiration.
Describe lung air pressure during inhalation?
Reduction of air pressure in lungs to below atmospheric pressure due to volume increase.
What’s Boyle’s law?
P inversely proportional to Volume.
Describe the pleural membranes.
1)visceral→ tightly covers the lunds
2)pariental→ lines the
Describe the relationship between the diaphragm and the thoracic cavity.
The diaphragm muscle lines the base of the thoracic cavity.
What holds the visceral and pariental pleura together?
Pleural fluid
Is there a space between the pleura?
There’s no interpleural cavity.
ONLY PLEURAL CAVITY!
Distinguish between forced and normal inspiration.
Normal is caused by the contraction of the diaphragm and the external intercoastal muscles.
Forced inspiration is caused by secondary muscles → scalenes and pectoralis minor
What’s the change in INTRAPULMONARY PRESSURE during normal inspiration?
-3mmHg BELOW ATMOSPHERIC PRESSURE
What’s the change in INTRAPULMONARY PRESSURE during forced inspiration?
-20mmHg
What contributes to normal expiration?
The elasticity of thorax and lungs that recoil after being stretched.
Is expiration passive or active?
Passive
What is the pressure increased to during normal expiration
+3mmHg
What contributes to forced expiration?
Intercoastal muscles and abdominal muscles
What is the pressure change during forced expiration?
+30mmHg
What type of mucles are respiratory muscles?
Skeletal- regulation of breathing!
What’s pleural pressure? Ppl
Pressure of pleural fluid
What’s the relationship between intrapleural and intra alveolar pressure?
intrapleural pressure is LOWER than intra-alveolar
In which way are pariental and visceral pluera pulled?
Visceral is pulled inward
Pariental pulled outward (part of thoracic cavity)
What’s the pressure gradient between intra-pleural and intra-alveolar pressure called?
Transpulmonary pressure
Why is transpulmonary pressure vital?
To keep pressure in lungs higher
Why is pressure in the intrapleural cavity so low?
The thoracic cavity stretches it outwards
The lunds stretch it in
Increase in volume due to <- →
Describe the intra-pleural pressure during inspiration and expiration
-6mmHg during inspiration
-3mmHg during expiration
What happens to transpulmonary pressure when pleural membranes are damaged and air flows in?
The air unsticks the pleural membranes
Define pneumothorax.
Collapsed lung.
What happens to lung volume due to pneumothorax?
Volume decreases as the visceral pleura no longer stretches the lung outward.
What’s the compliance of the lung?
Ability of the lung tissue to stretch and expand.
Define lung compliance.
The change in lung volume resulting from a change in TRANSPULMONARY PRESSURE
Equation for lung compliance
Cl= delta Volume / transpulmonary tissue
What’s the elasticity of the lung.
Ability of the lung to return rapidly to its original size.
What protein is responsible for the elasticity of lungs?
Elastin.
What happens to intrapulmonary (same as intralveolar pressure) during expiration.
Increased.
What happens to lung compliance in lungs with fibrotic tissue?
Compliance is reduced.
Less air moves in during inspiration.
= restrictive pulmonary disease.
What is degenerated in a patient with emphysema?
alveolar septa and pulmonary capillaries
→ compliance is increased
→ volume increased but doesn’t snap back
→ elasticity lost
→ expirary diifult
What else generates resistance to lung expansion?
Surface tension
What creates this surface tension?
SPHERICAL alveoli secrete a thin layer of fluid
→ presence of air increases surface tesnion
→ water molecules pull in towards the alveoli
→ opposed the expansion of lungs during inspiration
→ lung compliance decreased
Do smaller or larger alveoli have a greater surface tension?
smaller
What’s the law of laplace?
P= 2* T/r
→ divided by the radius
→ inward pressure
→more work needed to increase the volume of air in alveoli that are pulled inward due to surface tension
What does alveoli fluid contain to reduce surface tension?
Surfacts
What kind of biomolecule is a surfactant
Lipoprotein
What does the surfactant prevent?
Collapse ofsmaller alveoli during expiration
Do alveoli completely empty themselves?
No, there’s always residual volume
What type of alveoli produce surfactant?
Type II alveolar cells
When do type II alveolar cells develop?
Late foetal development
-25th week
What do premature infants (before 34th week) suffer from due to low type II development?
Acute respiratory distress syndrome
Acute respiratory distress syndrome- what does that do to the lungs?
Decreases lung compliance
Collapses Alveoli
Note
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