Review of pulmonary physiology Flashcards by Jonathan Paul Ladera

Main function of Lungs

continuous gas exchange

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Metabolic function of Lungs

Angiotensis I -> Angiotensin II

Removal of amines, arachidonic acid metabolites

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Metabolic function (PEPTIDES)

Angiotensin I - converted
Angiotensin II
Vasopressin
Bradykinin - 80% inactivated

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Metabolic function (Amines)

Serotonin - completely removed
Norepinephrine - 30% removed
Histamine
Dopamine

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Metabolic function (Arachidonic acid metabolites)

PG E2 and F2 - almost completely removed
PG A2
Prostacyclin
Leukotrienes - almost completely removed

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start of lung development

5th week AOG (Arise from ventral wall of the foregut)

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Level of Carina

T5 at expiration and T6 in inspiration

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Main bronchus that is prone to aspiration

RIGHT

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Boundary of Upper and Lower

Adults - vocal cords

pediatrics - cricoid cartilage

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T or F, Lower respiratory tract is sterile

False

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Boundaries of pleura and lungs ANTERIORLY

clavicle to 8th rib

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Boundaries of pleura and lungs LATERALLY

10th rib l

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Boundaries of pleura and lungs Posteriorly

level of T12

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ANTERIOR CHEST WALL (PE)

R Lung - UPPER and MIDDLE LOBE

L Lung - UPPER LOBE

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Type of airflow in conducting zone

bulk flow

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Type of airflow in respiratory zone

diffusion

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volume of anatomic dead space

150 ml

no gas exchange

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ADS + alveolar dead space

Physiologic dead space

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Overall volume that do not participate in ventilation

Physiologic dead Space

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Areas with ventilation but poor perfusion

alveolar dead space

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Chief sites of greatest resistance

Medium sized bronchi

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Part of the conducting zone where glands and cartilage first disappear

bronchioles

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cuboidal, non ciliated, secrete surfactants and GAGs

Clara cells

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site of gas exchange due to the presence of alveoli

RESPIRATORY ZONE

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Most of the lung volume is in the?

Respiratory zone - 3 L

volume that is inhaled and then exhaled with each normal breathing

Tidal volume -500ml

The maximum volume that can be exhaled from the resting end-expiratory level

ERV- 1100ml

The maximum volume that can beinhaled above a normal tidal inspiration

IRV - 3000ml

Volume remaining in lungs after maximum expiration (cannot be measured by spirometry)

RV - 1200ml

Maximum volume that can be inhaled from normal resting end-expiratory level

Inspiratory capacity - 3500ml

Volume remaining in lungs during regular breathing

Functional residual capacity

Maximum volume that may be exhaled following a maximum insiration or inhaled following a maximum expiration

Vital Capacity

Formula for Vital capacity

TLC - RV

Volume contained within the lungs following maximum inspiration

5800ml

Normal pulmonary capillary blood flow

70ml

Histology of bronchi

ciliated pseudostratfied columnar

Histology of bronchioles

cuboidal

Histology of alveoli

squamous

Ratio between thickness of submucosal mucus glands and wall thickness between epithelium and cartilage that covers the bronchi

REID index Normal : <0.4 Chronic bronchitis >0.4

Innervation of smooth muscle in the airway

parasympathetic

Type of receptor predominantly found in the airway

beta 2

Primary determinant of resting bronchomotor tone

cholinergic system

Decreases vagal tone

M1 and M3

autoinhibitory effect on acetylcholine release and have negative inhibitory effect

M2 receptor

Normal ciliary beating

12-15/sec

Bronchial glands

terminal bronchioles Parasympathetic control

Gel layer

Mucin +lipids

Sol layer

water + electrolytes

Liquid in Sol layer Regulation

Na channel cAMP mediated Cl channel cystic fibrosis transmembrane conductance regulator Ca activated CL channel

Cystic fibrosis

defective CFTR sweat gland test

Secretes glycosaminoglycans to protect bronchial lining

clara cells

Blood gas barrier

0.3-0.4 micron

Type I cells

flattend; forms 95% of alveolar wall

Type II cells

cuboidal, secretes surfactants (cytosomes) moremetabolically active

SUrfactants

Phospholipid Dipalmitoyl Phosphatidyl Choline

multilamellar bodies, precursors to pulmonary surfactants

cytosomes

Laplace Law

lager SA, smaller surface tension

Compliance

P/V

normal lung compliance =

0.15/L cm H2O

Compliance differ on inspiration and expiration for identical volumes

Hysteresis

Keeps airsacs open even in maximum exhalation

hysteresis

Lung is stiffer during?

inflation

Emphysema = high or Low compliance

High (decreased elastic recoil)

Fibrosis = high or Low compliance

LOW

point where pressure outside the airways and pressure inside the airways are equal

Equal pressure point

formula for Alveolar Pressure (Palv)

Pleural Pressure (Ppl) + Elastic Pressure (Pel)

When you inhale = more positive or negative?

more negative

Exhalation is an active or a passive process?

Passive

FEV1/FVC ratio of restrictive pathology

PRESERVED

FEV1/FVC ratio of Obstructive pathology

LOWE

Physiological attributes of COPD

airway obstruction + low elastic recoil

Trapped air due to inability to expel right amount

HYPERINFLATION

Dynamic hyperinflation

Unmasked during exercise Increased RR More aair trapped

SPace that lies between the epithelial basement membrane and the vascular basement membrane

Interstitium

Architectural framework of the lung

Interstitium

Cellular components of interstitium

Macrophages Mesenchymal cells Lympocytes

Major component of the EC matrix of interstitium

Collagen IV

Controls porosity of interstitium

Perlecan

Controls rigidity of interstitium

Hyaluronan

Diameter of alveolo-capillary membrane

10 um

time for oxgenation of each RBC

0.75 secs

Law governing diffusion of oxygen and carbon dioxide

Fick's law

Solubillity of CO2

20x than oxygen

Blood supply

Pulmonary arteries and veins

Flow of blood to thelungs/pulmonary capillaries

Perfusion (Q)

Flow of air into alveolar spaces

Ventilation (V)

More perfusion more ventilation (lobe of lung)

Lower lungs

Ventilation is greater where?

base due to lower interpleural pressure

At the upper lungs (Ventilation is __ compared to perfusion)

HIGHER

Bad ventilation, good perfusion

SHUNT

good ventilation, bad perfusion

Dead space

PULMONARY VS SYSTEMIC

Lower pressure in pulmonary Higher capacitance in pulmonary Less resistance in pulmonary

Most potent vasoconstrictor

Oxygen (hypoxemia)

Normal PaO2 sustainable for life?

60 mmHg

Increased O2 affinity, decreased O2 release

Shift to the LEft

Decreased O2 affinity, Increased O2 release

Shift to the right

Where do bleeding from hemoptysis comes from?

bronchial circulation

Central respiratory center

Medulla oblongata

Peripheral chemoreceptors

located in carotid artery and aortic arch bifurcation | Connected to the medulla via glossopharyngeal and vagus nerve

5 mechanisms causing hypoxemia

1. Low inspired O2 2. V/Q mismatch 3. Shunting 4. Decrease in diffusing capacity 5. Hypoventilation

hallmark of alveolar hypoventilation

paCO2 always increased

hallmark of Shunt

Hypoxemia is refractory to supplemental oxygen

ARDS

``` All the air sacs are filled with liquid Not able to ventilate NOT a vascular shunt No VENTILATION BUT PERFUSION CONTINUES Physiologic dead space is increased ```