Respiratory System Flashcards
What is Respiratory Physiology
Respiratory physiology is the study of how oxygen is brought into the lungs and delivered to peripheral tissues and how carbon dioxide is removed.
What are the functions of the respiratory system
Provides oxygen and eliminates carbon dioxide for homeostatic regulation of blood gases. Protects against microbial infection in an filtering action. Regulates blood in coordination with kidneys. Contributes to phonation, contributes to olfaction and reservoir for blood.
How is the respiratory system organized
Upper Airways Trachea Lungs Muscles of Respiration Rib Cage and Pleura
What makes up the upper airway of the respiratory system
They are the gateway to the lungs. It is made up of the nasal cavities, oral cavities, pharynx, and larynx.
What makes up parts of the lungs
Bronchi, bronchioles, alveoli, smooth muscles, connective tissue, and pulmonary circulation
What are upper airways
The upper airways will warm the air. The air travels from either the nasal cavity or oral cavity into the pharynx and then the larynx. The air then moves to the trachea.
What makes up the trachea and the bronchi
Trachea and primary bronchi are made up the c-shape cartilage and smooth muscle. Bronchi is made up plates of cartilage and smooth muscle. Bronchioles and terminal bronchioles there is only smooth muscle.
What is the process of continuous branching
We go from 1 branch being the trachea to upwards of 60,000 in the bronchioles.
What is the conducting zone
The conducting zone leads gas to exchanging region of the lungs, getting through the “anatomical dead space.” NO alveoli and NO gas exchange.
What is the respiratory zone
The respiratory zone is where the gas exchange happens and it contains alveoli.
Where is the higher surface area in the lungs
Even though the airways are smaller the more we progress into the lungs there is a higher surface area due to the sheer quantity of alveolar sacs and alveoli.
What are the alveoli in the lungs.
A tiny, thin-walled capillary-rich sac in the lungs where the exchange of oxygen and carbon dioxide takes place. There are about 500 million alveoli in the human lung and there are about 280 billion of capillaries in the lung.
What are type 1 alveoli
Most of the surface of alveolar walls are lined by a continuous monolayer of flat epithelial cells, they do not divide and they are susceptible to inhaled or aspirated toxins
What are type 2 alveoli
Type 2 alveolar cells (7% of alveolar surface) and produce SURFACTANT, a detergent-like substance made of lipoproteins that reduces the surface tension of alveolar fluid. They act as progenitor cells and when there is injury to type 1 cells they can be replaced by type 2 cells that can multiply and differentiate
What are the alveolar walls like
The alveolar walls also contain a dense network of capillaries and a small interstitial space (connective tissue and interstitial fluids)
How small are the capillaries in the alveolar walls
Capillaries are small (7 to 10 micrometers in diameter), just enough space for a red blood cell to pass.
How long do red blood cells spend in the capillaries of the respiratory system
Each red blood cell spends about 0.75 seconds in the capillary network and during this time probably traverses two or three alveoli.
How does Oxygen and Carbon Dioxide travel through respiratory membrane
The respiratory membrane is extremely thin and then can be easily damaged. Transfer of oxygen to carbon dioxide occurs by DIFFUSION through the RESPIRATORY MEMBRANE
What can damage the respiratory membrane
High blood pressure or too much pressure from intubation/respiration will distend the capillary and the rest of the respiratory circulation and may cause the epithelium to break; fluid/blood goes into the lungs and causes problems
What are the steps of Respiration
- Ventilation: Exchange of air between atmosphere and alveoli by bulk flow
- Exchange of Oxygen and Carbon Dioxide between alveolar air and blood in lung capillaries by diffusion
- Transport of Oxygen and Carbon Dioxide through pulmonary and systemic circulation by bulk flow
- Exchange of Oxygen and Carbon Dioxide between blood in tissue capillaries and cells in tissues by diffusion
- Cellular utilization of Oxygen and production of Carbon Dioxide
How is Respiratory Airflow (Ventilation) Produced?
- Central nervous system sends rhythmic excitatory (respiratory) drive to respiratory muscles
- Respiratory muscles contract rhythmically and in a very organized pattern
- Changes in volume and pressures at the level of the chest and lung occur
- Air flows in and out of the lungs
What are the respiratory muscles
Pump muscles
Airway muscles
Accessory muscles
What are the inspiration pump muscles
Diaphragm, external intercostals, parasternal intercostals
What are expiration pump muscles
Internal intercostals, and abdominal muscles
What are inspiration airway muscles
Tongue protruders, alae nasi, and muscles around the airways (pharynx and larynx)
What are expiration airway muscles
Constrictor muscles around the airways (pharynx and larynx)
What are inspiration accessory muscles
Sternocleidomastoid, scalene, and pectoralis.
How does the Diaphragm work
It is an inspiratory pump muscle and the most important muscle of inspiration. It is a dome shaped muscle which flattens during contraction (inspiration), abdominal contents are forced down and forward and rib is widened leading to an increase in volume of the thorax.
How does the external intercostal muscle work
It is an inspiratory pump muscle. It contracts and pulls the ribs upward increasing the lateral volume of the thorax and it moves in a bucket handle motion.
How does the parasternal intercostal muscle work
It is an inspiratory pump muscle. It contracts and pulls the sternum forward, increasing anterior and posterior dimensions of the rib cage. It works in a pump handle motion.
How do the abdominal muscles work
They are expiratory pump muscles. It is made up of external oblique, internal oblique, rectus abdominis, and transverse abdominis.
What do the abdominal muscles do at rest
They are relaxed at rest. They are involved in other physiological functions such as coughing, vomiting, defecation, and posture.
What do abdominal muscles do when you are active
Deeper, faster breathing requires active contraction of abdominal and internal intercostal muscles to return the lungs to its resting position. After exercise their goal is to return to the resting position
How do the internal intercostal muscles work
They are expiratory pump muscles. They are relaxed at rest. During exercise, internal intercostal muscles pull rib cage down, reducing thoracic volume
How do the accessory inspiratory work
Scalenes: Elevates upper ribs
Sternocleidomastoid: Raises the sternum
Pectoralis: Elevates ribs
These muscles contribute little to quiet breathing or at rest. They contract vigorously during exercise or forced respiration.
What muscles are involved during quiet inspiration
Quiet inspiration involves the external intercostal muscles and the diaphragm
What muscles are involved in forced inspiration
Forced inspiration involves the sternum, sternocleidomastoid, pectoralis, and diaphragm.
What muscles are involved in quiet expiration
During quiet expiration the diaphragm, and abdominal organs are involved
What muscles are involved in forced expiration
During forced expiration, the posterior internal intercostal muscles, diaphragm, abdominal muscles, and abdominal walls are involved. During forced (active) expiration abdominal muscles contract and push abdominal contents and diaphragm upward to reduce thoracic volume
How do upper airway muscles generate airflow
For inspiratory pump muscles to generate airflow, the upper airway must be open. Several muscles contribute to opening the upper airways and reduce airway resistance. These muscles include the tongue protruders, alae nasi, pharyngeal and laryngeal dilators for inspiration and pharyngeal and laryngeal constrictors for expiratory
What is obstructive sleep apnea
Reduction in upper airway patency during sleep such as snoring and sleep disturbances. This is caused by anatomical defects and a reduction in muscle tone. This is treated the CPAP machine called the continuous positive airway pressure
How does the conducting zone and “muco-ciliary escalator” work as filtering action
The conducting airways are lined by a superficial layer of epithelial cells which comprises mucus-producing (goblet) cells and ciliated cells. These cells function in a coordinated fashion to entrap inhaled biological and inert particulates and remove them from the airway.
How are deposited particles removed from the tracheobronchial tree
It is an effective clearance that requires both ciliary activity and respiratory fluids. The ciliated cells produce periciliary fluid (SOL LAYER) with low viscosity that is optimal for ciliary activity. Goblet cells produce mucus (GEL LAYER) distributed in patches that have high viscosity and high elastic properties and trap inhaled materials. The cilia movements downwards towards the nasopharynx and upwards towards the trachea.
What is the filtering action of the macrophages in the alveoli
It is the last defence against inhaled particles. They rapidly phagocytize foreign particles and substances as well as cellular debris. Silica dust and asbestos can cause pulmonary fibrosis and they kill the macrophages through disintegration.
What is spirometry
Pulmonary function test to determine the amount and the rate of inspired and expired air.
What are electronic spiromets
They act as airflow transducers. They digitally convert airflow rates and volumes into electronic signals, which can be digitally analyzed and displayed.
What is a spirometer
The spirometer is an apparatus used for measuring the volume of air inspired and expired by the lungs. It records the amount and rate of air that you breathe in and out over a period.
What is a spirogram
A test used to measure lung volume and capacities. The residual volume, functional residual capacity and total lung capacity cannot be measured by means of a spirometry test
What is residual volume
Residual volume is necessary and the amount of air that remains in the lungs after completely forced expiration - this is necessary, so our alveoli don’t collapse.
What is Tidal Volume
The volume of air moved IN OR OUT of the respiratory tract (breathed) during each ventilatory cycle.
What is Inspiratory Reserve Volume (IRV)
The additional volume of air that can be forcibly inhaled following a normal inspiration. It can be assessed by simply inspiring maximally to the maximum possible inspiration
What is Expiratory Reserve Volume (ERV)
The additional volume of air that can be forcibly exhaled following a normal expiration. It can be assessed by expiring maximally to the maximum voluntary expiration
How can you calculate residual volume
RV = FRC - ERV
RV: Residual Volume
FRC: Functional residual capacity
ERV: Expiratory Reserve Volume
What is Vital Capacity
The maximal volume of air that can be forcibly exhaled after a maximal inspiration
How can you calculate vital capacity
VC = TV + IRV + ERV VC: Vital Capacity TV: Tidal Volume IRV: Inspiratory Reserve Volume ERV: Expiratory Reserve Volume
What is Inspiratory Capacity
The maximal volume of air that can be forcibly inhaled
How do you calculate the inspiratory capacity
IC = TV + IRV
IC: Inspiratory Capacity
TV: Tidal Volume
IRV: Inspiratory Reserve Volume
What is functional residual capacity
The volume of air remaining in the lungs at the end of a normal expiration
How do you calculate functional residual capacity
FRC = RV + ERV
FRC: Functional Residual Capacity
RV: Residual Volume
ERV: Expiratory Reserve Volume
What is Total Lung Capacity (TLC)
The volume of air in the lungs at the end of a maximal inspiration
How do you calculate Total Lung Capacity
TLC = FRC + TV + IRV = VC + RV TLC: Total Lung Capacity FRC: Functional Residual Capacity TV: Tidal Volume IRV: Inspiratory Reserve Volume
What is minute (total) ventilation
Total amount of air moved into the respiratory system per minute
What is alveolar ventilation
Amount of air moved into the alveoli per minute. Alveolar ventilation is less than minute ventilation and it depends on anatomical dead space.
What are the effects that breathing pattern in alveolar ventilation
Increased DEPTH of breathing is more effective in increasing alveolar ventilation than an equivalent increase in breathing RATE
What is the forced expiratory volume in one second (FEV1)
A healthy person can normally blow out most of the air from the lungs in about 1 second
What is the ratio of FEV1:FVC (forced expiratory volume in one second:forced vital capacity)
The proportion of the amount of air that if blown out in 1 second.
What can a spirometry test show us
It can so us if the person is normal in regards to age, sex, weight, and height. We can also see if there is an obstructive pattern or a restrictive pattern.
What is an obstructive pattern
Patients affected by obstructive lung disease have shortness of breath due to difficulty in exhaling all the air from the lungs. Because of damage to the lungs or narrowing of the airways (bronchial constriction), exhaled air comes out more slowly than normal. At the end of a full exhalation, there an abnormally high amount of air that is still in the lungs
What can cause an obstructive pattern
Bronchial asthma, chronic obstructive disease and cystic fibrosis.
What does the spirometry test tell us about the obstructive pattern
FEV1 (forced expiration volume in 1 second) is significantly reduced
FVC (forced vital capacity) is normal/reduced
FEV1:FVC ratio is reduced.
What is a restrictive pattern
Patients affected by restrictive lung disease cannot fully fill their lungs with air. Their lungs are restricted from fully expanding. Restrictive lung disease most often results from a condition causing stiffness in the lungs themselves. In other cases, a stiffness of the chest tail, weak muscles, or damaged nerves may cause the restriction in lung expansion.
What causes restrictive patterns
Lung fibrosis, neuromuscular diseases (ALS, muscular dystrophy), or scarring of the lung tissues.
How does a spirometry show a restrictive pattern
Reduced vital capacity
FEV1 is reduced (forced expiratory volume in 1 second)
FVC is reduced (forced vital capacity)
FEV1:FVC is above average
What is the Helium Dilution Method
Helium is insoluble in blood and after several breaths, the helium will equilibrate. The concentration is measured at the end to see if there is an expiratory effort increase/decrease.
What are the static properties of the lung
Mechanical properties when no air is flowing (which are necessary to maintain lung and chest wall at a certain volume)
What are dynamic properties of the lung
Mechanical properties when the lungs are changing volume and air is flowing in and out (which is necessary to permit airflow)
What is ventilation
Exchange of air between the atmosphere and the alveoli (bulk flow - gas moves from high pressure to low pressure)
What is Boyle’s Law
For a fixed amount of an ideal gas kept at a fixed temperature, P [pressure], V [volume] are inversely proportional, so while one increases, the other decreases
P1V1 = P2V2 at a constant temperature
According to Boyle’s Law what happens when there is no net movement of air
Pressure between the two areas (atmosphere and alveoli) will have no net movement of the air
According to Boyle’s Law what happens the alveoli experiences an increase in volume
The alveoli increases in volume and decreases in pressure. The air moves from the atmosphere in the alveoli.
According to Boyle’s Law what happens where is an increase in pressure in the alveoli
When the alveoli decreases in volume and increases in pressure, the air moves from the alveoli to the atmosphere.
How do you get airflow
Once pressure difference is generated between inside and outside of lung, air moves via the flow from region of high pressure to the region of low pressure.
What happens to pressure and volume during inspiration
During inspiration we will increase the pulmonary volume the alveolar pressure (PALV) will decrease and increasing the atmospheric pressure (PATM)
What happens to pressure and volume during expiration
During expiration we will decrease the pulmonary volume, the alveolar pressure (PALV) increases to more than the atmospheric pressure (PATM) leading to an overall decreased pulmonary volume.
What is lung pressure
Lung pressure involved in lung volumes and in the movement of air and out of the lungs
What pressures are impacted during inspiration and expiration
During inspiration and expiration, the air moves in and out the lungs due to the variations in the intrapleural pressure (PIP), alveolar pressure (PALV), and transpulmonary pressure (PTP)
What is the pleurae
The pleurae form a thin double-layered envelope. The parietal pleura covers the thoracic wall and superior face of the diaphragm. The visceral pleura covers the external surface of the lung
What is the intrapleural fluid
There is ~10 mL and it reduces the friction of lungs against thoracic wall during breathing, it is extremely thin between 5-35 micrometers
What determines lung volume determined by
The interaction between the lungs and the thoracic cage determines the lung volume.
What is the elastic recoil of lung and chest wall
The lungs tend to collapse because of their elastic recoil. The chest wall tends to pull the thoracic cage outward because of their elastic recoil. At equilibrium, the inward elastic recoil of the lungs exactly balances outward elastic recoil of the chest wall.
How does the lungs and the chest wall interact
This interaction between lungs and chest wall does not occur by direct attachment but through the intrapleural space between the visceral and parietal pleura
What is intrapleural pressure (PIP)
Intrapleural pressure (PIP) is the pressure within the pleural cavity. It fluctuates with breathing, but it is always subatmospheric due to the opposing directions of the elastic recoil of lungs and thoracic cage. It acts as a relative vacuum.
What happens if the intrapleural pressure (PIP) and the alveolar pressure (PALV) are the same
If the Intrapleural pressure (PIP) equals alveolar pressure (PALV) the lungs would collapse
What is alveolar pressure (PALV)
Alveolar pessure is the air inside the alveolar. When the glottis is open and no air flows into and out of the lungs, the pressures in all parts of the respiratory tree, including the alveoli (PALV), are equal to atmospheric pressure. Alveolar pressure (PALV) is a dynamic event, directly involved in producing air flow
