Respiratory Physio Flashcards
Lung Marker
Functional Residual Capacity
No gas exchange
Conducting zone
Nose to terminal bronchioles
Conducting zone
With gas exchange
Respiratory zone
Respiratory bronchioles, alveolar ducts, alveolar sacs
Respiratory zone
How many generation of airways do you find in the respiratory system?
23
How many alveoli are present in the respiratory system?
500 million
500 ml
Tidal Volume
An atomic dead space
150 ml
Physiologic dead space
350 ml
Maintain oxygenation even in between breaths
Residual volume
Maximum amount exhale/inhale
VC / vital capacity
Alveolar pressure = atmospheric pressure (equilibrium
FRC
Left sided heart failure
Alveolar Macrophage
Associated with hemolysis
Bronchial blood vessels
What is the sympathetic effect on the smooth muscles of the airways?
Relaxation (Beta 2)
What is the parasympathetic effect on the smooth muscles of the airways?
Contraction (Muscarinic receptors)
For gas exchanges with 96 - 98% surface area
Type 1 pneumocyte
Small, cuboidal, found at the corners of alveoli, for surfactant production with 2-4% surface area
Type 2 pneumocyte
Keep alveoli free of dust and debris
Alveolar macrophages
In CHF: may convert to siderophages/ Hemosiderin-laden macrophages
Alveolar macrophages
Produce mucus
Goblet cells, submucosal glands
In COPD: hyperplasia, hypertrophic seen
Goblet cells, submucosal glands
May play a role in epithelial regeneration after injury by secreting protective GAGs
Clara Cells/ Club Cells
Carries DEOXYGENATED Blood to the lungs (respiratory bronchioles, alveolar ducts, alveoli)
Pulmonary Circulation
“Sheet” arrangement
Pulmonary Capillaries
Carries OXYGENATED BLOOD to the lungs (conducting airways & surrounding tissues)
Bronchial Circulation
Pulmonary veins returns to Left atrium alone
Pulmonary circulation
Capable of Angiogenesis
Bronchial circulation
1/3 returns to right atrium via bronchial veins
2/3 returns to the left atrium via pulmonary veins
Bronchial circulation
4 basic lung volumes
IRV
TV
ERV
RV
4 lung capacities
IC
FRCVC
TLC
Cannot be measured directly by spirometers
FRC
IRV
RV
TLC
Amount of air inspired/expired during quiet breathing
TV
Maintains oxygenation in between breaths
RV
Equilibrium/Resting volume of the lungs
FRC
Marker of Lung function
FRC
Differences among sexes
Lung volumes and capacities 20-25% lower in females
Factors that increase VC
Body size, male gender, conditioning, youth
Asthma, COPD,
Obstructive
Interstitial lung disease
Restrictive
Which of the following lung volumes or capacities can be measured by spirometers
Vital Capacity
Refers to the amount of air left in the lungs after a regular normal exhalation?
Functional residual capacity
Anatomic dead space + alveolar dead space
Physiologic dead space
Air in the conducting zone
Anatomic dead space (150 ml)
Air in the alveoli not participating in gas exchange due to V/Q mismatch
Alveolar Dead Space (9 mL)
Total rate of air movement in/out of the lungs
Minute Ventilation
Minute ventilation corrected for physiologic dead space
Alveolar Ventilation
What happens to the FEV1 and FVC in patients with obstructive and restrictive lung diseases?
Decreases
What is the FEV1/FVC ratio of a healthy person?
80%/ .8
What happens to the FEV1/FVC ratio in patients with obstructive and restrictive lung disease respectively
Obstructive: decreased
Restrictive: normal to increased
A 60 year old male patient came to the clinic complaining of exertion all dyspnea, he presents with some muscle wasting, increase anteroposterior diameter of the chest, O2 seats were 92% on ambient air auscultation revealed occasional wheezing on both lung basest (-) crackles, (-)bipedal edema, (-) Orthoptera, PND, patient is a known 40 pack year smoker. X-ray revealed hyper aerated lung fields, low set diaphragm. What is the expected finding in spirometers?
Decreased FEV1
All of the following are true statements pertaining to the patient above except?
A. There is decreased are for gas diffusion due to alveolar destruction
b. There is increased lung compliance
C. There is decreased lung recoil
D. There is decreased airway resistance due to loss of tethering effect
D. There is decreased airway resistance due to loss of tethering effect
His ABG reaves ad pH=7.35 PCO2 = 5- HCO3 28 PO2 90, which of the following is correct?
A. Has acute respiratory acidosis
B. Has acute respiratory alkalosis
C. There is a shift of the hemoglobin dissociation curve to the left
D. There is decreased affinity of hemoglobin to oxygen
D. There is decreased affinity of hemoglobin to oxygen
Do: respiratory acidosis with renal compensation
After a month, the patient had a severe exacerbation leading to acute respiratory failure which necessitated mechanical ventilators, patients condition was stabilized with latest ABG after 12 hours showed pH 7.47 PCO2 30 HCO3 24 PO2 95 Fi)2 40% VT 500 mL AC mode RR 16 PEEP 5. What is the next best step?
Decrease the RR to 12
Forced Inspiration
External intercostals, SCM, anterior serrati, scalene, Alae Nasir, genioglossus, arytenoid
Inspiration
Ribs upward and outward; abdominal contents downward
Forced Expiration
Internal intercostals, reclusive abdominal, internal and external oblique, transversus abdominis
Expiration
Ribs downward and inward, abdominal contents upward
Pathology: loss of elastic fiber Compliance: increased Elasticity: decreased FRC: increased Effects: barrel shaped chest
Emphysema
Pathology: stiffening of lung tissue Compliance: decreased Elasticity: increased FRC: decreased Effects:
Fibrosis
Force caused by water molecules at the air-liquid interface that tends to minimize surface area
SurfaceTension
Cell that produces surfactant
Type 2 pneumocyte
Main component of surfactant
Water
Active component of surfactant
Dipalmitoyl-phosphatidylcholine (DPPC) / Lecithin
Mechanism for DPPC reducing surface tension
Amphipathic nature (Hydrophobic and hydrophilic)
Effect of surfactant on lung compliance
Increase
Start of surfactant production
24th week AOG
Maturation of surfactant
35th week AOG
Test for surfactant
Amniotic L:S Ratio
Treatment for newborn RDS
Steroids, Surfactant
Airway resistance
Poiseuille’s law
Major site of airway resistance
Medium-sized bronchi
Factors affecting Airway Resistance
Bronchial smooth muscle
Lung volume
Viscosity/density of inspired gas
Ability of the respiratory membrane to exchange gas between the alveoli and the pulmonary blood
Diffusing Capacity
Diffusing capacity for O2
At rest: 21 ml/min/mmHg
Maximal Exercise: 65 ml/min/mmHg
Diffusing capacity for CO2
At rest: 400 - 450 ml/min/mmHg
Maximal Exercise: 1200 - 1300 ml/min/mmHg
What are the forms of gases in solution?
Dissolved gas, bound gas, chemically modified gas
What is the only form of gas that contributes to partial pressure
Dissolved gas
What is the only gas in inspired air found exclussively as dissolved gas?
Nitrogen
Decrease in arterial PO2
Hypodermic
Used to compare causes of hypo emit
A-a gradient
Normal A-a gradient
< 10 mmHg
Decreased O2 deliver to the tissues
Hypoxia
Which of the following causes of hypoxia is characterized by a decreased arterial PO2 and an increased A-a gradient?
Right to left cardiac shunt
All of the following conditions causes both a decrease in PaO2 and increase in A-a gradient except?
A. Pulmonary fibrosis
B. V/Q of 0 or low V/Q state like airway obstruction
C. Right to left cardiac shunt
D. High altitude sickness
High altitude sickness
Gas equilibrates with the pulmonary capillary near the start of the pulmonary capillary
Diffusion of gas increased only by increasing blood flow
Perfusion-Limited Gas exchange
Gas does not equilibrates even until the end of the pulmonary capillary
CO and O2 during strenuous exercise and disease states (emphysema, fibrosis)
Diffusion-Limited Gas Exchange
O2 transport rest
Perfusion-Limited
O2 transport during exercise and diseased state
Diffusion-Limited
O2 transport in high altitude
Slow
Equilibration of O2 at sea-level
1/3 length of Pulmonary Capillary
Equilibration of O2 at high altitude
2/3 length of Pulmonary Capillary
Percentage of Dissolved O2
2%
Percentage of O2 bound to HgB
98%
HgB with attached O2
Oxyhemoglobin
HgB without attached O2
Deoxyhemoglobin
HgB with Fe3+; doesn’t bind O2
Methemoglobin
a2y2, higher affinity for O2
Fetal hemoglobin (HbF)
aA2Bs2 sickles RBCs, less affinity for O2
Hemoglobin S
Max O2 binding with HgB
O2-binding capacity
% of blood that gives up its O2 as it passes through the tissues
Utilization Coefficient
Binding of first O2 molecule increases affinity for second O2 molecule and so forth
Exhibits Positive Cooperativity
Increased UNLOADING of O2 to HgB
Increased P50
Due to increased Carbon Dioxide, Acidosis, 2,3 BPG, Exercise, Temperature
Shift to the Right
Increased BINDING of O2 to HgB
Decreased P50
Due to Increased Carbon Monoxide, HbF
Shift to the Left
Cherry red appearance
CO poisoning
A patient was found one winter evening by her relatives at home in a comatose state right beside the gas heater, labs revealed normal PaO2 and O2 saturation of 97%, what is the most likely condition?
CO poisoning
The condition in the patient above causes which of the following physiologic effects?
Left shift of the oxyhemoglobin dissociation curve
In relation to the patient above, which of the following is true if P50 of HgB was found to have gone down to 20 mmHg?
Affinity of hemoglobin to O2 increases
90% of CO2 in the blood
HCO3
5% of CO2 in the blood
Dissolved CO2
3% of CO2 in the blood
Carbaminohemoglobin
Cl HCO3 exchange in the RBC
Chloride shift (using Band 3 Protein)
O2 affecting affinity of CO2/H to HgB
Haldane Effect
CO2/H affecting affinity of O2 to HgB
Both Effect
Haldane
Lungs
Bohr
Body tissues
Pulmonary circulation: Pressure
< systemic circulation
Pulmonary circulation: Resistance
< systemic circulation
Pulmonary circulation: Cardiac Output
= systemic circulation
Pulmonary BLood Flow: Supine
Same through the entire lung
Pulmonary blood flow: Standing
Lowest at the apex, high at the base
Effect of hypoxia (low PAO2) on pulmonary Arterioles
vasoconstriction
Causes of pulmonary global hypoxia vasoconstriction
High altitude, fetal circulation
Other lung vasoactive substances
TXA2
PGI2
Causes bronchi constriction
Leukotrienes
Local alveolar capillary pressure < alveolar air pressure throughout the cycle
Zone 1
Local alveolar capillary systolic pressure > alveolar air pressure during systole but less than that during diastole
Zone 2
Local alveolar capillary pressure > alveolar air pressure throughout the cycle
Zone 3
No blood flow
Zone 1
Intermediate blood flow
Zone 2
Continuous blood flow
Zone 3
What lung zones do we see in the APEX of the lungs?
Zone 2, 3
What lung zones do we see in the BASE of the lungs?
Zone 3
What lung zones do we see in a supine position, or during exercise THROUGHOUT THE LUNGS?
Zone 3
What lung zones do we see in cases of PULMONARY HEMORRHAGE or POSITIVE PRESSURE VENTILATION?
Zone 1
Which one will show decrease in arteriole PO2 - Right-to Left Shunts or Left-to-Right Shunt?
Right to Left Shunts
