Pulmonary 1 Flashcards by Kari Git

Inspiratory Reserve Volume (IRV)

The additional volume person is CAPABLE of inhaling after normal, quiet inhalation

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Tidal Volume (TV)

Volume of air inhaled and exhaled during normal breathing ~500mL

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Residual Volume (RV)

Volume remaining in lungs after maximal exhalation

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Expiratory Reserve Volume (ERV)

The additional volume person is CAPABLE of exhaling after normal, quiet exhalation

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Total Lung Capacity (TLC)

Volume of gas in lungs after maximal inhalation
~7L
TLC = TV + RV + ERV + IRV

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Vital Capacity (VC)

Max volume of air that can be exhaled AFTER maximal inhalation

VC = TV + IRV + ERV

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Functional Vital Capacity (FVC)

Vital Capacity measured at maximum force

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Inspiratory Capacity (IC)

Maximum volume that can be inspired after expiration after normal quiet breathing

IC = TV + IRV

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Functional Residual Capacity (FRC)

Volume remaining in lungs after normal TV exhaled

FRC = ERV + RV

With Helium:
(C1)(VS) = (C2)(VS + FRC)
FRC = (VS) x (C1/C2-1)

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Define the Conducting and Gas exchange Airways

Conducting
Mouth to Terminal Bronchioles
ONLY air movement
No Gas Exchange
Branch up to 23 times
Radius decreases with each branch
Anatomical Dead Space ~150 mL

Gas Exchange Airway
Respiratory bronchioles to Alveoli
GAS EXCHANGE/Surfactant production

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Type I and Type II alveolar cells

Epithelial cells

Type I = GAS EXCHANGE
Very Thin

Type II = SURFACTANT
NO Gas Exchange

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Two important concepts about the lungs from top to bottom

Gravity- Blood pressure will be lower at the top and Higer at the bottom
Stretch- Amount of stretch from top to bottom depends on the mass below that point (SLINKY)

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Resistance and area, formula and relationship

R ~ 1/A

Area = (Pie)r2

R ~ 1/(Pie)r2 or R ~ 1/r2

Resistance in the conducting zone will increase with each branch until we get to the Respiratory zone where surface area greatly increases and resistance is almost nothing.

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Two Important cells in conducting airways

Goblet cells- produce mucus
Prevents large things like
sand from getting to alveoli
Everywhere above alveoli
Including respiratory bronchioles
Ciliated cells move mucous up and out
Located where goblet cells are

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Alveolar macrophages

Dust cells- Phagocytose Pathogens

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Clara Cells and Goblet cells relationship

Clara cell are secretary cells in terminal bronchioles, they increase in number the further down we are in the bronchioles, while, goblet cells decrease/are absent in terminal bronchioles

Kulchitke cells

Neuroendocrine cells secrete paracrine factors and part of diffuse neuroendocrine system.

Relationship of pressure flow and resistance in lungs.

Pulmonary circulation is low pressure, low resistance and high flow, think Ohms law (Flow equals change in pressure over resistance)

Best vascularized area in body, 100% ob blood from RA goes through the lungs which is the same as the mat of blood gsong through the rest of the body. It MUST BE LOW RESISTANCE

If we decrease resistance, we increase flow. Ohms law

Important features of Respiratory Zone.

Respiratory bronchioles and alveolar ducts
Cross sectional area increases, but MOST IMPORTANTLY - Surface area increases allowing for gas exchange
Velocity of flow decreases-gas stops and comes back out
Ficks

Ficks Principal

Ficks = (Area)(Diffusion)(C1-C2)
———————————-
T

C = concentration or it can be pressure P1-P2
T= Thickness of membrane
Thinner the wall, easier the gas exchange
Larger the area the greater the gas exchange
Diffusion = how well a particular molecule diffuses

Fused Basal Lamina

Basement membrane of capillary lumen and Type I cells of alveoli fuse together to form fused basal lamina. Used for gas exchange.

Whole Body Plethymograpy

Based on Boyle’s law

P1)(V1) = (P2)(V2
Used for measuring FRC

What can Spirometry measure an not measure

It can measure all the components of Vital Capacity (TV, ERV, IRV)

It CANNOT measure residual volume so we measure functional residual capacity with helium

What are the primary functions of FRC?

O2 reserve/bank when needed
Keeps intrapleural pressure negative
IS maximizes FRC
Point when elastic recoil and chest wall are balanced

Ventilation of exhaled air MINUTE VENTILATION

Ve = R x VT Ve is always larger than Va because some air is in the conducting airways Ve~7.5 L/min (500 L/breath, 15 breaths/min)

Alveolar ventilation

Ventilation of respiratory zones of the lungs Va = R (VT - VD) Va = Ve - VD Va ~ VD~ 150 ml/breath, at 15 breaths per minute VD is approximately 2.25 L/min

Determining Dead Space

Volume of Gas that does not eliminate Co2 VD = PaCo2 - PECo2 ----- ---------------------- VT PaCo2 Simplified: VD = VT x PaCo2 - PECo2 ---------------------- PaCo2 PaCo2 = Arterial Co2 PECo2 = Exhaled Co2 Assume arterial Co2 = Alveolar Co2

Partial pressures of room air compared to that of inspired gas

Room Air = 21% O2 and 79% N2 Ptot = (0.21 x 760) + (0.79 x 760) Inspired gas = is humidified H2O takes up ~ 47mm Hg Ptot still must equal 760 PItot = 47mmhg + (0.21 x (760-47)) + (0.79 x (760- 47)) If someone has a fever the partial pressure of H2O will increase leaving less room for O2

What is unique about the Pressure of alveolar O2

Must consider the exchange of O2 and Co2. Assume PaCo2 = PACo2 arterial = Alveolar Must consider metabolism as well Respiratory exchange quotient = 0.8 on a mixed diet PAO2 = PIO2 - (PaCo2 / R) = 150 - 50 = 100 So from a blood gas we can figure out PAO2 This will also change at different altitudes

Alveolar gas equation at SEA LEVEL Define each equation

PAO2 = FiO2 x (760-47) - pACo2/R ~100mmHg PAO2 = partial pressure of alveolar oxygen FiO2 = Fractional concentration of inspired O2 760 = total brometric pressure of the atmosphere at sea level in mmHg 47 Partial pressure of water vapor in alveolus pACo2 = Partial pressure of Co2 coming from blood in mmHg R = Respiratory exchange quotient

What is the Respiratory exchange quotient?

The amount of Co2 generated per O2 molecule utilized At basal metabolic rate it is 0.8

What is the pressure of Arterial 02

In a healthy inividual at sea level ~95 mmHg

What is a normal Alveolo-arterial gradient When will it change

Alveolar pressure at sea level is ~100, so the Alveoli-arterial gradient ranges from 5-10 mmHg It is INCREASED when there is a diffusion problem, Alveolus to artery Problem in ANY non-ventilated or poor diffusion space

DLco and related formulas What will make DLco cage and why?

DLco = (A/T) x Dco DLco = Vco /PAco we get values using Ficks law Vgas = A x Diffusion constant X (P1-P2) ----------------------------------------------- Thickness Deco give us lung diffusion for for CO and tells us how well gasses (O2) will diffuse across a membrane DLco DECREAESES as someone gets sick- as someone gets thicker O2 will struggle more to cross the membrane than CO2, this is because CO2 is soluble in blood This is why we give O2 - OXYGEN will help if diffusion is really poor

Explain the lung Zones

Zone I = alveoli most stretched and capillaries most compressed (Low ventilation because alveoli already stretched, least profusion) Zone II =Alveoli mediumly stretched and capillaries medium size Zone III = Alveoli least stretch and blood vessels largest. (Most Profusion, most ventilation because the smaller UNSTRETCHED alveoli will get the most flow)