Vol.3-Ch.1 "Pulmonology" Flashcards
What are Intrinsic risk factors VS Extrinsic risk factors and what is the major example of each for pulmonary diseases?
Intrinsic Risk Factors are those that are influenced by or from within the patient. The most important one is Genetic Predisposition
Extrinsic Risk Factors are those that are external to the patient. The most important on is cigarette smoking (another big one is environmental pollution)
What are the 3 parts of the upper airway?
What is the major function of the upper airways?
- Nasal Cavity
- Pharynx
- Larynx
The are mostly in charge of humidifying, warming, and purifying the air we breath.
How is air filtered and warmed in the nose?
It is filtered by a combo of the nose hairs in the anterior portion of the nose and by mucus on the walls of the posterior, the mucus is constantly made by the goblet cells in the mucous membrane and moved toward the posterior portion of the nose via Cilia (thin fingerlike projections that contract one way) until it reaches the back and is swallowed.
Air is warmed because the air flows over the Kiesselbach’s Plexus in the lower nasal septum (a rich supply of blood vessels, also the most common cause of nose bleeds)
What are the 4 sinuses of the upper airway?
- Frontal
- Ethmoid
- Sphenoidal
- Maxillary
What are the 3 divisions of the Pharynx?
- Nasopharynx
- Oropharynx
- Laryngopharynx
What are the 3 pairs of cartilage that form the larynx?
How are the vocal cords formed?
- Thyroid Cartilage
- Cricoid Cartilage
- Epiglottis
The vocal cords (there are two pairs) are formed by folds in the internal lining of the larynx. The upper ones (Vestibule) form the false vocal chords and the lower pair form the True Vocal Chords.
During inspiration both cartilage pairs are wide open and separated and the epiglottis sits upright allowing air in, but when swallowing the epiglottis tips backwards and the cartilage pairs close, opening the esophagus.
How can smoking negatively affect the trachea?
It destroys the Cilia that help to move the mucus that trap foreign particles moving it towards the pharynx (backwards in this case, and makes it to where coughing is the only safety mechanism to remove foreign particles
What is the Carina?
It is where the trachea deviates into the left and right mainstem Bronchi.
It has a lot of nerve endings and stimulation of these will produce a violent cough
Starting from the Trachea, what is the flow of tissues/organs that air flows down to for gas exhange?
- Trachea
- Carina
- Right and Left Mainstem Bronchi
- Secondary (Lobar) Bronchi
- Tertiary (Segmental) Bronchi
- Bronchioles
- Terminal Bronchioles (approx. 22 divisions of
bronchioles) - Respiratory Bronchioles (at this level, gas exchange
can occur) - Alveolar Ducts
- Alveoli or Alveoli Sacs
After how much damage to surface area in the alveoli is there no longer enough area for gas exchange for a resting patient?
2/3
What is the difference between the right and left mainstem bronchi?
The right bronchi essentially is just a continuation of the trachea (does angle off much) whereas the left mainstem bronchi angles more acutely.
This is why most food or liquids aspirated go into right lung as well as an ET tube pushed too far may pass the carina and will often go into right mainstem bronchi
**So if you don’t hear left side air flow on auscultation, it may be because you are too far
Approximately how many alveoli are there in the lungs?
What 3 things make up the Respiratory Membrane?
300 million
The alveolar lining, supportive tissue (elastin fibers), and capillaries
What is surfactant in the lungs and what does it do?
It is a chemical secreted by type II cells on the alveolar surface that keeps the alveoli moist and open
What is a physiologic shunt?
It is when blood passes through alveoli without gas exchange and is normal in small amounts, (approximately 2% of blood flow to the lungs)
How many lobes are in the right and left lungs?
The right lung has 3 divisions
The left lung has 2 divisions
(b/c it has the heart it leans against)
Visceral Pleura VS Parietal Pleura?
Visceral Pleura is the pleura that lines the lung tissues and contains no nerves.
Parietal Pleura is the pleura that lines the thoracic cavity and contains nerves
A small amount of fluid separates the two to reduce friction by lubrication
Where does the lungs pleural lining actually connect to the lungs?
At the Hilum, where the bronchi and blood vessels enter the lungs
Pulmonary Vessels vs Bronchial Vessels?
The pulmonary vessels are the pulmonary veins and arteries that transport blood from the heart for gas exchange and then back to the heart (left atrium).
The Bronchial vessels are the bronchial arteries and veins that supply blood to the muscles of the lungs themselves via an extension off the aorta, and the veins drain back into the superior vena cava
What are the 3 major processes that allow for gas exchange to occur?
- Ventilation: the mechanical process of moving air in
and out of the lungs - Diffusion: Process by which gases move between the
alveoli and the pulmonary capillaries - Perfusion: the circulation of blood through the lungs
or more specifically the pulmonary capillaries
Why is oxygen so important to our bodies?
It allows for aerobic respiration required for healthy cellular metabolism
What body structures must be intact for ventilation to occur? (5x)
- chest wall
- nerve pathways
- diaphragm
- pleural cavity
- brainstem
What part of the brain controls ventilation and what nerve sends that signal to the diaphragm?
The Medulla; since expiration is mostly passive the inspiration center of the medulla is much more active.
(the hypothalamus, pons and other voluntary portions of the brain can effect this, the medulla is just responsible for at rest, involuntary breathing)
The Phrenic Nerve sends the impulse to the diaphragm
**the Intercostal Nerves also receive the impulse
On what side of the rib do the associated artery, vein, and nerve lay?
The inferior side
Inspiration VS Expiration
The two divisions of ventilation
INSPIRATION:
- Diaphragm contracts (flattens)
- Intercostal muscles contract, expanding the chest
cavity both laterally and anteroposteriorly
- Decreases chest cavity pressure by 1-2mmHg below
ATM
- It is always an ACTIVE process, requiring energy
EXPIRATION:
- Chest wall and diaphragm relax
- Increases chest cavity pressure by 1-2 mmHg above
ATM
- It is a passive process requiring no energy (unless
patient has emphysema or is exercising)
What is the pressure of the pleural space and why is it necessary?
The pleural space has a negative pressure of 4-8 mmHg in order to ensure that the chest wall and lungs move in concert
Airway Resistance VS Lung Compliance
Another two factors to ventilation
- Airway Resistance: is the drag to the flow of air coming into or out of the lungs. The greatest factor here are the medium sized bronchi which are made of smooth muscle and can constrict when irritated as will asthma or anaphylaxis
- Lung Compliance: is the ease with which the chest expands aka the change in volume of the chest cavity that results from a specific change in pressure within the chest cavity.
The two major factors here are Age, as you get older you loose elasticity in the muscles, ribs, and cartilage of the chest wall which result in a shrunken chest wall. And Emphysema patients who have damage to the elastic tissue holding alveoli together and small so they have very high compliance which means little pressure change occurs even with large lung volume expansion
What are the different lung volumes? (x7)
What factors effect lung volumes?
- Total Lung Capacity: 6,000ml
- Vital Capacity: 4,800mL
a) Inspiratory Reserve: 3,000mL
b) Tidal Volume: 500mL
c) Expiratory Reserve: 1,200mL - Residual Volume: 1,200mL
- Dead space: 150mL
Inspiratory Capacity = insp. res. + tidal
Functional Residual Capacity = exp. res. + residual vol.
Vital Capacity = insp. res. + tidal + exp. res.
(the total air inhaled and exhaled in one breath)
Volume of air entering is dependent on metabolic needs of pt.
Age, sex, physical conditioning, medical illness can alter lung volumes
How do you calculate the Minute Respiratory Volume of a patient?
Minute Alveolar Volume?
Min. Resp. Vol. = Tidal Volume X Respiratory Rate
Min. Alveolar Vol. = (tidal - dead space) X Resp Rate
Alveolar Dead Space VS Anatomical Dead Space
Alveolar Dead Space is air that is in alveoli that are damaged or dead and cannot be used for gas exchange
Anatomical Dead Space is air that is in the trachea, mainstem bronchi, and bronchioles during inspiration or expiration that cannot be used for gas Exchange (approx. 150mL)
What is the Hering-Breuer Reflex?
It is the mechanism the prevents over inflation of the lungs; this is achieved by the Stretch Receptors in the visceral pleura and on the walls of the bronchi/bronchioles that are directly responsible for shutting off the Medulla’s impulses for inflation when the lungs are adequately inflated.
In a healthy Pt what is the most important determinant of the ventilatory rate?
What senses this?
Arterial PCO2 is the most important factor for ventilatory rate
As arterial PCO2 levels increase (more CO2) the pH of blood drops or becomes more acidic. As blood pH decreases this is also reflected in the pH of the cerebrospinal fluid (which bathes the brain and spinal cord) which is sensed by the MEDULLA that initiates increased vent rate.
There are also specific sensors in the aorta and carotid artery that are sensitive to PCO2 and will send a chemical messenger to the medulla.
What Pt is not as sensitive to PCO2 changes and therefore relies more on PO2 to get feedback for vent changes?
A COPD patient will have decreased responsiveness to changes in arterial PCO2, and will therefore lean on a delicate balance between PO2 levels being low enough to stimulate the medulla and high enough for maintenance of body function. This can be seen as low as 50-60mmHg in COPD patients
What is the concentration of O2 and CO2 in:
- Alveoli
- Arterial Blood (going to lungs)
- Venous Blood (going to heart from lungs)
Alveoli:
104mmHg O2
40mmHg CO2
Arterial Blood/Capillaries:
40mmHg O2
45mmHg CO2
(Remember gases will diffuse from high to low concentration)
Venous Blood Returning to the heart from the lungs post gas exchange will have:
104mmHg O2
40mmHg CO2
Lung Perfusion is dependent on what 3 things?
- Adequate Blood Volume (& hemoglobin
concentration) - Intact Pulmonary Capillaries
- Efficient pumping of blood via heart
What is Hemoglobin?
It is a protein transport unit which has 4 Iron containing Heme molecules and a protein containing globin portion. The O2 binds to the heme, and once one O2 binds to it, the hemoglobin changes so that it can more readily take up other O2 molecules and vice versa when releasing. This is seen by the Oxygen Dissociation Curve
What % of O2 is transported via hemoglobin?
98% is transported via hemoglobin
2% is transported by O2 diffusion into plasma
What can change the O2 dissociation curve? (4x)
Right Shift occurs in: (decreased O2 affinity)
- Decrease pH
- increase CO2
- increase Temp
- increase 2,3-BPG
Left Shift occurs in: (increase O2 affinity)
- Increase pH
- Decrease CO2
- Decrease pH
- Decrease 2,3-BPG
Bohr Effect VS Haldane Effect?
Bohr Effect:
When hemoglobin are at a tissue site and saturated with oxygen, a CO2 molecule will bind to the hemoglobin, which makes the hemoglobin have a higher affinity for CO2 and will thus release it’s O2 for more CO2
The Haldane Effect:
When the CO2 rich hemoglobin get to the lungs, it is released into the alveoli b/c of the lower concentration there. As O2 then take the place of the CO2, the hemoglobin becomes more acidic which causes the release of more of the CO2.