Jump to Radiology - A pulmonary consolidation is a region of (normally compressible) lung tissue that has filled with liquid, a condition marked by induration of a normally aerated lung. It is considered a radiologic sign. Consolidation occurs throug
Jump to Radiology - A pulmonary consolidation is a region of (normally compressible) lung tissue that has filled with liquid, a condition marked by induration of a normally aerated lung. It is considered a radiologic sign. Consolidation occurs throug
Jump to Radiology - A pulmonary consolidation is a region of (normally compressible) lung tissue that has filled with liquid, a condition marked by induration of a normally aerated lung. It is considered a radiologic sign. Consolidation occurs throug
– provides rigid conduits for air to reach gas exchange sites is?
the conducting zone
cleanses, warms and humidifies incoming air this is?
the conducting zone
Each lung is: surrounded by pleurae and connected to the mediastinum by vascular and bronchial attachments:
lung root
– called the ?
The anterior, lateral and posterior lung surfaces lie in close contact w the ribs:
costal surface
– form the?
base
The lungs – concave inferior surface:
Blood Supply to the Lungs 2 circulations:
– pulmonary and – bronchial
Systemic venous blood that is to be oxygenated in the lungs is delivered by?
pulmonary arteries
– lie anterior to the main bronchi this is?
pulmonary arteries
– and branch profusely along w bronchi this is?
pulmonary arteries
– pulmonary arteries finally feed into:
– pulmonary capillary networks
– surrounding the alveoli is?
– pulmonary capillary networks
– convey freshly oxygenated blood to the heart this is?
– pulmonary veins;
The pulmonary circuit is a what type of circulation?
low-pressure, high-volume circulation
– lung capillary endothelium is an ideal place for NZs that act on blood such as?
ACE NZs that inactivate prostaglandins
Provide oxygenated systemic blood to lung tissue is?
– bronchial arteries
Arise from the aorta enter lungs at the hilum run along branching bronchi
– bronchial arteries
– provide a high-pressure, low-volume supply
– bronchial arteries
– of oxygenated blood to all lung tissues – except alveoli
– there are multiple anastomoses between the two circulations
pulmonary veins
– and most venous blood returns to the heart via?
Innervation of the Lungs
– ANS – visceral sensory
– innervated by both branches of?
Innervation of the Lungs
pulmonary plexus on lung root
– Nerve fibers enter each lung through the?
– run along bronchial tubes and blood vessels
pulmonary plexus on lung root
Alveoli
type I alveolar cells
The walls are composed primarily of (90%): a single layer of squamous epi cells called?
Account for most of our lung volume
Alveoli
Provide a huge surface area for gas exchange
Alveoli
type I alveolar cells surrounded by a ?
flimsy basement membrane
Alveoli
pulmonary capillaries
External surfaces covered w a cobweb of?
The Respiratory Membrane is made up of the?
capillary and alveolar walls
Two simple squamous cells w a very thin membrane between them blood flowing by on one side: air on the other this is?
The Respiratory Membrane
Scattered among the type I alveolar cells are?
Cuboidal type II alveolar cells
Cuboidal type II alveolar cells (10%) these cells secrete?
surfactant
– 3 other significant alveolar features they are?
1. they are surrounded by fine elastic fibers 2. open alveolar pores connect adjacent alveoli 3. alveolar macrophages crawl freely
alveolar pores Allow equalization of air pressure and provide alternate air routes to alveoli whose bronchi have collapsed in disease this is? Old dead ones are swept up and away by cilia to pharynx this is?
alveolar macrophages
The Pleurae – form a thin, double-layered serosa – parietal pleura – visceral pleura – covers thoracic wall and superior face of the diaphragm
– parietal pleura
– continues around the heart and between the lungs
– forming the lateral walls of mediastinal enclosure
– parietal pleura
– snugly enclosing the lung root
– covers the external lung surface
– visceral pleura
– dipping into and lining its fissures
pleurae produce?
pleural fluid
fills the slit-like pleural cavity between them is?
pleural fluid:
– the suction of excess pleural fluid into lymphatics
pleural layers
– maintains a slight suction between?
contributes to adherence to the thoracic wall this is?
Lung Lymphatic Drainage
– inflammation of pleura
Pleurisy
Pleurisy- often results from?
pneumonia
Pleura become rough, resulting in friction as pleurisy progresses, pleurae may produce?
excessive amounts of fluid
– relieves pain but hinders breathing
Pleurisy
– general term for fluid accumulation in pleural cavity:
– pleural effusion
– other fluids that may leak into pleural cavity include:
blood blood filtrate
Pleural Effusion – blood from?
leaked from damaged vessels
Pleural Effusion – blood filtrate from?
From lung capillaries with left side congestive heart failure
Mechanics of Breathing: Pulmonary Ventilation
– inspiration:
consists of 2 phases:
– expiration:
– inspiration & expiration: – these are mechanical processes that depend upon?
– volume changes in the thoracic cavity
Gases always expand to?
fill their container
Volume changes lead to?
pressure changes
Pressure changes lead to the?
flow of gases
– gives the relationship between the pressure and volume of a gas
Boyles Law
Boyles Law
– gives the relationship between the pressure and volume of a gas
Boyles Law at a constant temperature what occurs?
– the pressure of a gas varies inversely w volume
Boyles Law mathematically stated as? Boyle’s Law – gases always fill their container thus in a large container gas molecules will be?
Far apart and the pressure will be low
Boyle’s Law – if the volume of the container is reduced gas molecules will be?
Forced closer together and the pressure will rise
respiratory pressures are always described relative to?
– atmospheric pressure (Patm)
– atmospheric pressure (Patm) is described as?
– the pressure exerted by the air surrounding the body – at sea level = 760 mmHg = 1 atm
– a negative respiratory pressure indicates:
– the pressure is lower than atmospheric
– 4 mmHg =
756 mmHg
– 756 mm Hg is know as what in that region?
“absolute pressure”
A positive respiratory pressure is what compared – is higher than atmospheric to atmospheric? Zero respiratory pressure is what to atmospheric?
Equal to atmospheric
– is the pressure in the alveoli
Alveolar (Intrapulmonary) Pressure (Pa)
– it rises and falls with breathing
Alveolar (Intrapulmonary) Pressure (Pa)
– alveolar pressure is zero (equal to atmospheric)
At the end of respiration, w the glottis open? what is the aveolar pressure?
As are all pressures in the respiratory tree to cause air to flow into alveoli during inspiration:
fall to below atmospheric (below 0)
– alveolar pressure must?
– pressure in the pleural cavity is?
Pleural (Intrapleural) Pressure (Pip)
Pleural (Intrapleural) Pressure (Pip) fluctuates with breathing but pleural pressure is always?
~ 4 mmHg less than alveolar
Pleural is always negative relative to?
alveolar (very important that it’s always negative)
What causes the negative intrapleural pressure?
syphoning of fluid from the pleural cavity by the lymphatics
The collapse tendency of the lungs is about how many mmHg?
4 mmHg
The pleural pressure must be at least as negative to?
keep the lungs expanded
– 2 forces tend to make the lungs collapse
1. natural elasticity of the lungs 2. the surface tension of the alveolar fluid
1. natural elasticity of the lungs
smallest size possible
– tendency to recoil: always assume?
2. the surface tension of the alveolar fluid
constantly acts to draw alveoli to smallest size
Molecules of fluid lining alveoli attract each other this produces surface tension that do what?
Lung Collapsing Forces are Opposed by?
-Natural elasticity of the chest wall – a force that tends to pull thorax outward – And enlarge the lungs
There are opposing forces that exist in the thorax. The net result is a?
negative pleural pressure (Pip)
The negative pleural pressure is very important because it?
holds the lungs to the thoracic wall
Any condition that equalizes Pip w Pa causes?
immediate lung collapse
Atelectasis AKA?
Alveolar Collapse
Atelectasis: Alveolar Collapse occurs when?
– bronchiole becomes plugged -chest wound -rupture of the visceral pleura
Atelectasis: Alveolar Collapse
the associated alveoli absorb all their air and collapse
What happens with alveoli?
the difference between alveolar and pleural pressures
Transpulmonary Pressure
transpulmonary pressure forumla is?
Pa – Pip
what keeps air spaces open (it keeps the lungs from collapsing) at the end of a normal expiration:
transpulmonary pressure
Transpulmonary Pressure
4 mmHg
– 0 – (- 4 mmHg) =
The size of the transpulmonary pressure determines the?
size of the lungs at any time
the greater the transpulmonary pressure the
larger the lungs
Back to Pulmonary Ventilation: Inspiration
enlarging the thorax
The inspiratory muscles contract to cause?
The diaphragm contracts moving how?
Inferiorly
and doing what?
Increasing the height of thorax
– external intercostals contract causing?
– lifting ribs increasing diameter of thorax
Back to Pulmonary Ventilation: Inspiration – this increases the thoracic volume by?
500mL
Expansion of the thorax during inspiration causes?
– stretches the lungs and alveolar volume increases
Expansion of the thorax during inspiration stretches the lungs and alveolar volume increases so what happens with alveolar pressure?
alveolar pressure drops
Anytime alveolar pressure is less than atmospheric what happens with air?
– air rushes into the lungs along its pressure gradient
Pleural Pressure during Inspiration
~ – 5 mmHg
– about 1mmHg below atmospheric
– at the beginning of inspiration pleural pressure is what mmHg?
Pleural Pressure during Inspiration
more negative pressure: ~ – 7 mmHg
– Then during inspiration expansion of the chest pulls outward on the lungs and creates?
Pleural Pressure during Inspiration – inspiration ends when:
NRG must also be expended to overcome other factors that hinder pulmonary ventilation – such as?
Airway Resistance the relationship between?
gas flow (F) pressure (P) resistance (R)
Airway Resistance equation is?
– F = ΔP/ R
The amount of gas flowing into and out of the alveoli is directly proportional to the?
-change in pressure -the pressure gradient between the atmosphere and the alveoli
or the?
Usually, small changes in the pressure gradient produce?
large changes in volume of air flow (F)
the average pressure gradient during normal quiet breathing is how many mmHg?
2mmHg or less
The average pressure gradient during normal quiet breathing is ~ 2mmHg or less and that is sufficient to move how many mL of air with each breath?
500 ml of air with each breath
gas flow varies inversely with
resistance
Gas flow decreases as resistance does what?
increases
Airway resistance is usually insignificant because of what issues?
1. airway diameters are huge relative to the low viscosity of air 2. as airways get smaller, there are more branches
Airway resistance is usually insignificant because:
huge
1. airway diameters are huge relative to the low viscosity of air 2. as airways get smaller, there are more branches – so the total cross-sectional area is what size?
At any gas-liquid boundary molecules of liquid are more strongly attracted to each other than to what?
gas
At any gas-liquid boundary molecules of liquid are more strongly attracted to each other than to the gas
surface tension
This unequal attraction produces a state of tension at the liquid surface called?
draws liquid molecules closer together (contracts Surface tension them) Water is composed of highly polar molecules and has a very high surface tension.
reduce alveoli to their smallest size
As the major component of the film coating alveolar walls it is always acting to?
If fluid was pure water, alveoli would collapse between breaths but surfactant (produced by Type II alveolar cells) causes what?
– decreases cohesiveness of water molecules
Surfactant
Less NRG is needed to expand the lungs and discourage alveolar collapse
– reduces surface tension of the alveolar fluid
– Decreases cohesiveness of water molecules – Reduces surface tension of the alveolar fluid This causes?
– Fetal lungs don’t produce adequate surfactant
last two months of development
– until when?
– Babies born before that are unable to keep alveoli inflated between breaths
– spray surfactant into airways – use devices that maintain positive airway
– treatment is?
pressure
Lung Compliance A measure of the change in lung volume that occurs with a change in transpulmonary pressure this is known as? distensibility of the lungs AKA?
Lung Compliance
– the greater its compliance So the more a lung expands for a given rise in transpulmonary pressure how is the compliance? The higher the compliance the easier it is to?
expand the lungs
Lung Compliance is determined by 2 factors:
1. distensibility of the lung tissue (generally high if healthy) 2. alveolar surface tension (surfactant keeps this ¯)
Healthy lungs tend to have what kind of compliance?
high compliance
Any decrease in the natural resilience of the lung diminishes compliance what is the compliance status? Chronic inflammation or infections causes?
fibrosis (scar tissue to replace normal tissue) decreased surfactant secretion
decreased surfactant secretion fibrosis
-lower lung compliance -more NRG is needed to breathe
What happens with compliance?
Factors that reduce thoracic compliance hinder lung expansion such as what?
deformities of thorax ossified costal cartilages
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