Respiratory system Flashcards
What is expiratory capacity?
This is the maximum amount of air that you are able to breathe out of your lungs
EC= Tidal volume expiratory +ERV
What is Air flow = to?
Flow = Patm -Palv /R
What is the respiratory membrane?
It is the layers that the air has to pass through to get to the blood
Epithelial cell membranes (x2)
Basement membrane
Blood capillary membranes (x2)
How many secondary bronchioles are on the right side?
3 secondary bronchi serve the 3 lobes of the right side
Right has Trinity
How does histamine cause bronchoconstriction?
Histamine is an inflammatory chemical released locally that will trigger the smooth muscle to constrict to prevent the allergen from entering the body
In the end it also makes breathing difficult by decreasing airway size, increased mucus production and overall increased resistance
What are the air passages from pharynx to lungs?
Larynx
Conducting zone
Respiratory zone
What is forced vital capacity?
The maximum volume inhaled followed by exhalation as fast as possible
What is FEV1 ?
% of FVC that can be exhaled within 1 second
What is transpulmonary pressure?
Transpulmonary pressure= Palv -Pip
This is the pressure that determines whether the lung expands or not.
Negative = collapse (pressure pushes against lung)
Positive= expand (pressure is lower than inside lung)
What are the air passages of the head and neck?
- Nasal cavities
- Oral cavities
- Pharynx
What drives the movement of air into and out of the lungs?
Pressure gradients cause air to move from areas of high pressure to low pressure
When does inspiration occur?
Pressure in the lungs is less than atmospheric pressure so air moves from high (outside) to low (inside)
Why is the residual volume of air in the lungs important?
This volume of air prevents the lungs from collapsing
What 3 factors affect compliance normally?
- Elasticity of lungs
- Surface tension
- Elasticity of chest wall
What is the difference between internal respiration and external respiration?
- Internal respiration refers to oxidative phosphorylation
External respiration refers to
Pulmonary ventilation (bringing air in and out)
* Exchange between lungs and blood
* Transport in blood
* Exchange between blood and body tissues
How does CO2 affect the size of bronchioles?
⇑⇑⇑CO2 LEVELS
Metabolic rate is increasing so gas exchange needs to increase to meet the demand
Airways will bronchodilate to increase the amount of air entering the lungs
Blood flow will also increase to increase gas exchange rate
What is the Residual volume (RV)?
1200ml
This is the amount of air that remains in the lungs to keep the alveoli open even after the maximum amount of air is expired from the lungs
What effect does obstructive lung disease have on volumes and capacities?
Expiration Reserve Volume decreases
Residual volume increases
Total lung capacity increases
Vital capacity decreases (ERV⇣)
How does elasticity affect compliance?
The lungs can easily expand but they also want to recoil to expire
If the lungs have a lot of scar tissue (fibrous) they will not be able to stretch as much decreasing compliance, but increasing elasticity in that the lungs want to snap back once expanded.
If the elastin in the lungs decreases in emphysema the lungs will be compliant in stretching and taking a lot of air in, but it will not be able to recoil/ snap back to expire resulting in the air staying in the lungs => Barrel chest
What is Boyle’s law?
Pressure is inversely related to volume
How does epinephrine affect the airway resistance?
Epinepherine will bind to beta receptors in the airways and trigger them to bronchodilate
Relaxation of smooth muscle
What is the Vital capacity (VC)?
This is the amount of air that you can bring in during normal inspiration and expiration and forceful inspiration and expiration.
VC= TV+ ERV+IRV
How does COPD affect airway resistance?
Increases the airway resistance on a long term basis
Emphysema leads to destruction of alveoli leading to destruction of the respiratory zone
Loss of airway elasticity
How does bronchoconstriction affect the airway resistance?
The smooth muscle surrounding the airways constrict decreasing the size of the airway lumen.
As the Area decreases the resistance increases and the flow of air becomes harder
What is a pneumothorax and why does it make it hard to breathe?
Pneumothorax is the presence of ATMOSPHERIC AIR within the pleural space which increases the pressure placed against the lung.
Increasing intrapleural pressure makes the transpulmonary pressure negative causing the lung to collapse
What is the tidal volume?
500ml
The amount of air we breathe in unforced in a single breath (inspiration & expiration)
(like when we are not thinking about it)
What factors determine intra-alveolar pressure?
Quantity of air in the alveoli
Volume of alveoli
How is the resistance to the air flow in the lung kept relatively constant?
Conducting zone bronchi have a large diameter
Total cross sectional area of bronchioles is huge as the vessels get smaller they increase in number
What is the minute respiratory volume?
Total amount of air that flows in or out of the respiratory system in 1 minute
What is inspiratory capacity (IC)?
This is the maximum amount of air that you can bring into the lungs
IC= Tidal volume inspiratory + IRV
What is surface tension?
- This is where water molecules on the surface of the water experience a net inward pull by neighboring/ deeper water molecules causing them to move closer together forming a film (become more compacted)
- Some may be pulled from the surface creating a vacuum that remaining molecules are attracted to creating surface tension.
- As the molecules move closer together to fill in the gaps this surface area decreases
- Air-water interface tries to have the least surface tension in general
Where do cartilage rings stop in the lungs?
Smaller bronchi are the last bronchi after tertiary to have cartilage plates
Bronchioles and terminal bronchioles do not have cartilage
What prevents the lungs and the pleural sac from separating?
Surface tension (attraction) of intrapleural fluid prevents the wall and lungs from pulling apart
What is the intra-alveolar pressure?
Pressure of the air within the alveoli (lungs)
Palv= 760mmHg
How many secondary bronchi are on the left side of the lung?
2 on the left side sere 2 lobes of left lung
How do passive forces affect airway resistance?
How does a loss in the elasticity of the chest wall affect compliance?
When we get older cartilage begins to ossify making it hard for the chest to expand making the chest wall less compliant.
What is compliance in relation to the lungs?
Ease with which lungs can be stretched (expanded)
Lung compliance= Change in volume/ Change in (alveolar pressure-intrapleural pressure)
What is restrictive respiratory disease?
This is where the lungs ability to expand is restricted so the compliance is affected or the ease with which the lungs can stretch.
Respiratory muscles, ribs, rib attachment, ossification of cartilage, pneumonia, pulmonary fibrosis (collagen fibers replace elastic fibers)
Recoil is high because lungs not expanding enough will readily return to a smaller size
What does airway resistance refer to?
The resistance of the entire airway in the respiratory system.
Like the Total peripheral resistance in cardio
When does expiration occur?
When pressure in the lungs becomes greater than atmospheric pressure
air moved from inside lung outside
How does bronchodilation affect airway resistance?
The smooth muscle surrounding the airway relaxes causing a increase in the radius of the airway.
Resistance decreases and air flow becomes easier
What is the mucus escalator?
The motion of moving the mucus from the lungs up to the mouth via the wave-like motion of the pseudostratified ciliated columnar epithelium.
How does surface tension affect compliance?
Air-water interface causes a decrease in the surface area causing the collapse of the alveoli
As the alveoli decrease in size it will ⇓⇓⇓⇓ in volume there is ⇑⇑⇑⇑ pressure causing it to be harder for the lungs to expand with air volume
More surface tension = harder to expand lungs= ⇓⇓⇓⇓ compliance
What are expiratory muscles? List them!!
Decreases volume of thoracic cavity
Internal intercostals
Abdominal muscles
What are the structures of the respiratory zone?
Respiratory bronchioles
Alveolar ducts
Alveoli
Alveolar sacs
What is the Expiration Volume reserve (ERV)?
1000ml
This is the maximum amount of air that can be expired from the lungs beyond the tidal volume expiration.
What is the functional residual capacity (FRC)?
This is the amount of air that is present in your lungs after tidal volume.
FRC= ERV + RV
Does the parasympathetic nervous system cause relaxation or constriction of smooth muscle in airways?
Constriction
When relaxing the body does not require that much oxygen
As the alveolar volume decreases what happens to the pressure?
Lungs will recoil causing an increase in the pressure in the alveoli as the volume decreases
Air is driven out of lungs
What is the epithelium of the respiratory zone?
Epithelial cell layer of alveoli
Endothelial cell layer of capillaries
What are the difference between type 1 and type 2 alveolar cells?
Type 1 makes up alveoli wall
Type 2 secrete surfactant that help keep the walls of the alveoli separated and open
What is the pleura?
The serous membrane (pleura sac) surrounding each lung and lining the chest wall.
Intrapleural space is filled with intrapleural fluid to reduce friction during ventilation
What is the function of the conducting zone?
It is a passageway that increases the temperature of air to body temperature and humidifies it so it can easily diffuse into the blood.
What volumes are affected in restrictive lung disease?
If not enough air is entering the lung due to low compliance and high recoil these volumes will be smaller
Inspiratory Reserve volume
Expiratory Reserve volume
Residual volume
What does a larger lung compliance mean?
Easier to inspire because the volume increases easier (decrease in pressure)
Smaller change in transpulmonary pressure needed to bring in a given volume of air
What causes resistance to air flow in the lungs?
Airway radius
Mucus
Why are pulmonary function tests necessary?
They help to differentiate between obstructive and restrictive pulmonary diseases
How does Inspiration occur?
- Neural stimulation of the inspiratory muscles (phrenic nerve)
- Diaphragm contracts flattening out and moving downward
- External intercostals contract makes ribs pivot up and outward expanding the chest wall
- Thoracic cavity volume increases
- Outward pull on pleura decreases intrapleural pressure and increases transpulmonary pressure
- Alveoli expand
- Alveolar pressure decreases
- Air flows into alveoli by bulk flow
What capacities are affected in restrictive lung disease?
Forced Vital Capacity decreases
Total lung capacity decreases
Vital capacity decreases
What is Passive expiration?
No energy is expended to push air out of the lungs
- Inspiratory muscles stop contracting
- Lungs and chest wall recoil to original positions
- Volume in the thoracic cavity decreases
- Pressure in the thoracic cavity increases
What is the Inspiratory reserve volume (IRV)?
3000ml
This is the amount of air that you bring into the lungs beyond the tidal volume.
Forceful breath
How do surfactants reduce surface tension and increase lung compliance?
Surfactants have a hydrophobic tail that interacts with air and a hydrophilic head that interacts with water.
Hydrophobic tail experiences an attraction to the air (upward pull)
Hydrophilic head experiences an attraction in 3 directions by the neighboring water molecules
Additionally attraction of the water to the hydrophilic head reduces the downward pull on the water surface
Net pull on the alveolar surface is canceled allowing the alveoli to remain open and expanded
⇡⇡⇡⇡Volume ⇣⇣⇣⇣ Pressure ⇡⇡⇡⇡Compliance
What factors affect airway resistance?
- Passive forces
- Contractile activity of smooth muscle
- Mucus secretion
What is active expiration?
The contraction of muscles is used to create a greater and faster decrease in the volume of the thoracic cavity
Why is intra pleural pressure negative?
Elasticity in lungs and chest wall
When we breathe in expanding the lungs it has the tendency to want to recoil inward.
Elasticity of the lungs makes it want to snap back to its smallest original position.
As we inspire the chest wall wants to expand pulling the parietal pleura away from the lungs
Result in overall increase in volume of intrapleural space and decrease in pressure
What are the muscles of the thoracic cavity?
Internal and external intercostals
Diaphragm
What is meant by anatomic dead space in the conducting zone of the lungs?
Air is present in the conducting airways which does not move into the blood for gas exchange. It stays within the conducting zone
150 mL of air
What are inspiratory muscles? List them!!
Muscles that increase volume of thoracic cavity
Diaphragm
External intercostals
What is the function of the respiratory zone?
Gas exchange between the blood and air
As the alveolar volume increases what happens to the pressure?
Pressure decreases causing the alveoli to expand as air flows in
What is teh forced expiratory volume?
This is the amount of air that you can force out of your lungs within the first second
What is the Intrapleural pressure?
Pressure inside of the pleural sac surrounding the lungs
Pip =756mmHg
What controls the contractile state of smooth muscles?
Extrinsic control (SNS & PSNS, hormones)
Intrinsic control (Histamine & CO2)
What is the total lung capacity (TLC)?
This is the total volume of air that can occupy your lungs
TLC= RV+ IRV +ERV +TV
What is the conducting zone made up of?
Larynx (glottis, epiglottis)
Trachea
Bronchi
Secondary bronchi
Tertiary bronchi
Bronchioles
Terminal bronchioles
Does the sympathetic nervous system cause relaxation or constriction of smooth muscle in airways?
Relaxation
Allows for more air to get into the lungs un order to escape danger
How does astha affect airway resistance?
Increases airway resistance via broncospasms (spastic contractions of the smooth muscle in bronchioles)
Increases mucus production
Inflammation of the bronchiole walls decreases airway size
What is Forced Expiratory volume (FEV)?
Percentage of FVC that can be exhaled within a certain time frame
What is the epithelium of the conducting zone?
Goblet cells => secrete mucus
Ciliated cells => move particles towards the mouth
