Pulmonology A&P Flashcards
What divides the upper and lower respiratory tract?
the larynx (below the vocal cords is lower respiratory tract)
Conducting Zone vs Respiratory Zone
- conducting zone: transfers air to and from the lungs
- nose, pharynx, larynx, trachea, bronchi, to terminal bronchioles
- Respiratory Zone: site of gas exchange at alveoli
- respiratory bronchioles, alveolar ducts, alveoli
Where is the trachea located
anterior to esophagus, extends from larynx to ~T5
What is located in the mediastinum?
heart, esophagus, trachea, great vessels
Location of Oblique fissures and Horizontal fissure (R lung)
- oblique fissures: T3 spinous process to 6th rib mid-clavicular
- Horizontal fissure (R lung): 4th rib anteriorly, to 5th rib at mid axillary line
Parietal pleura has what type of sensation?
pain sensation in response to injury or inflammation: Phrenic nerve (refers pain C3,C4, C5)
- phrenic nerve also innervates mediastinal and diaphragmatic part
Visceral Pleura and lung tissue have what type of sensation?
- have visceral sensory reflexes but no pain sensation
- have parasympathetic innervation from Vagus nerve CNX
- also innervated by sympathetic fibers from the sympathetic trunks
- will have visceral reflexes such as cough and stretch reflexes
Type I Alveolar Cells
simple squamous epithelium supported by elastic basement membrane
Type II Alveolar Cells
secrete surfactant
- surfactant: lipoproteins
- coats the alveoli to reduce surface tension to prevent collapse of alveoli
Alveolar Macrophages
aka dust cells, mononuclear phagocytes
- engulf debris and prepare it for removal via lymph nodes
Inspiration
- passive (resting): diaphragm contracts
- external intercostals contracts
- active (forced or strained):
- sternocleidomastoid and scalenes contract
Expiration
- passive (resting:
- diaphragm relaxes
- active (forced, strained):
- internal intercostals
- abdominal muscles
Transmural Pressure Gradient
the difference in pressure between the pleural cavity and the atmosphere or alveoli
- approx -4mmHg
- normal atmospheric pressure: 760mmHg
High Compliance vs Low Compliance
- high compliance: loose, easy inflation
- typically destruction of airspace or decreased elasticity
- ex: emphysema
- typically destruction of airspace or decreased elasticity
- Low compliance: stiff, hard to inflate
- typically connective tissue changes or fluid build up
- ex: fibrosis, edema, ARDS
- typically connective tissue changes or fluid build up
PO2 deoxygenated vs oxygenated
Po2 deoxygenated = 40mmHg
PO2 oxygenated = 100mmHg
PCO2 at the tissues versus the alveoli
PCO2 at tissue = 46mmHg
PCO2 at alveoli = 40mmHg
V/Q ratio
- V= airflow (ventilation)
- Q = blood flow (perfusion)
- normal V/Q (ventilation/perfusion) ratio on average ~0.8
- ***highest ventilation and perfusion are both highest at the base of the lungs***
What causes high V/Q?
ventilation > perfusion
blockage of blood flow → no gas exchange
What causes low V/Q?
ventilation
- blockage of airway → diverted away from non-ventilated alveoli to areas of better ventilation → SHUNT
What causes decreased hemoglobin saturation and increased oxygen unloading?
- increased temp
- increased CO2
- increased H+ levels
- shifts the hemoglobin saturation curve to the Right
What causes increased saturation of the hgb and decreased oxygen unloading?
decreased temperature
decreased CO2 levels (ph> 7.6)
Chloride Shift
HCO3- is returned to the plasma through HCO3- channels that swap Cl- for HCO3-
When CO2 enters the blood via diffusion gradients at tissue what happens to it?
- slow reaction, converts to HCO3- when it interacts with water in the plasma
- fast reaction, converts to HCO3- quickly in RBCs due to enzyme carbonic anhydrase
- the HCO3- rxn reverses at the lungs to release CO2 and CO2 is transported out of the plasma into the alveoli
Central Chemoreceptors and Breathing
- sense pH changes in the CSF
- CO2 enters the CSF through the BBB
- pH decreases when CO2 = high
- low CSF pH = increased breathing rate
- Note: become insensitive to chronically high levels of CO2
Peripheral Chemoreceptors
- directly detect pH, CO2, and O2 in the arterial circulation
- low pH and high arterial CO2 = increased breathing rate
- low O2 (only very low <60mmHg) = increased breathing rate
Bronchiolitis obliterans
fibrotic changes permanently scar the lungs, occlude airways
Atelectasis
collapse of lung tissue that occurs due to a variety of conditions
- compression atelectasis: external pressure on lungs due to tumors, pneumothorax, abdominal torsion
- absorption atelectasis: obstructed or hypoventilated alveoli from inhalation of concentrated O2 or anasthesia
- Surfactant Impairment: decreased production in premature infants, ARDS, anesthesia, mechanical ventilation
- ***post surgical care = deep breathing, ambulation, position changes***
Parenchyma
the functional tissue of an organ, excluding the connective tissue and the supportive tissue
First line medication for smoking cessation
varenicline (chantix)
- varenicline use with nicotine replacement products should generally be avoided → can cause n/v, headaches, dizziness, GI upset
Smoking Cessation Options
- varenicline (Chantix)
- nicotine replacement products
- antidepressants
- bupropion
- nortriptyline
Nicotine Withdrawal
a theory says that a drop in dopamine release in the brain after long periods of exposure to nicotine leads to mood disorders, cravings for tobacco, and other sxs
Cystic Fibrosis and Genetics
mutation in the CFTR gene
autosomal recessive
Asthma and Genetics
- asthma runs in families
- polygenic, multifactorial disorder
- ADAM33, filigrin and other genes associated with atopy are associated with asthma
Alpha-1-antitrypsin deficiency
inherited disorder that may lead to lung and liver disease
- this deficiency causes neutrophil elastase to destroy alveoli and cause lung disease (like emphysema/COPD)
- the abnormal alpha-1 antitrypsin can also accumulate in the liver and cause damage
- Environmental Factors: tobacco smoke, chemicals and dust can also impact the severity of this deficiency
- autosomal dominant with codominance features
Sarcoidosis and genetics
both environmental and genetic factors
- siblings of patients with sarcoidosis are 5x as likely of developing sarcoidosis
- HLA (human leukocyte antigen) alleles have been consistently associated with sarcoidosis susceptibility
