CLIN PATH I: EXAM #2 (PULM - Obstructive Lung Dz)

What are the main physiologic roles of the lungs?

1. make o2 available to tissues

2. remove CO2 (metabolic byproduct)

Each lobe is demarcated by:

visceral pleura

Difference between pleural effusion and pulmonary edema:

pleural effusion - pleura

pulmonary edema - alveoli

Inspiration is _____ and expiration is ________

active; passive (due to recoil - except w/ exercise)

What maintains the anatomic integrity of the lungs?

connective tissue (collagen/elastic structures - supports and maintains patency)

surfactant (reduces surface tension allowing for expansion)

Proximal conducting airways are:

ciliated pseudostratified columnar epithelial (cilia beat in unison to transport FB out)

As airways further branch, smooth muscle and secretory glands are:

reduced

Smallest conducting, non respiratory airways are:

bronchioles (cuboidal epithelium - may or may not be ciliated)

What causes asthma?

bronchial smooth muscle constriction (closes up airways)

Where do lymphatic vessels arise from?

beneath visceral pleural and in deep plexuses at junction of terminal bronchioles and alveoli

Where should the alveolar fluid move to gain access to draining lymphatics?

terminal bronchioles

Where do the lymphatic ducts travel?

peribroncovascular sheath to hilar and mediastinal lymph nodes (before going to the left or right thoracic ducts)

There is no _______ in lymph

protein

Lymphatic drainage of the pleural space occurs through plexuses that are:

anatomically separate from pulmonary lymphatics

What do efferent parasympathetic (muscarinic cholinergic) fibers of the lungs cause?

bronchoconstriction

pulmonary vasodilation

mucous gland secretion

What do efferent sympathetic fibers of the lungs cause?

bronchial relaxation

pulmonary vasoconstriction

inhibition of secretory glands

What should you stimulate during asthmatic rxns?

sympathetic nerve fibers

What does the efferent non-adrenergic non-cholinergic system do in the lungs?

inhibition of events (including bronchodilation)

**ATP, NO, peptide NT

Afferent pulmonary nerve functions:

1. bronchopulmonary stretch receptors

2. irritant receptors

3. C fibers/juxtacapillary receptors

1. bronchopulmonary stretch receptors (lung inflation, bronchodilation, inc HR)

2. irritant receptors (cough, mucus secretion, bronchoconstriction)

3. C fibers/juxtacapillary receptors (response to chemical/mechanical stimuli causing a rapid shallow breath pattern, mucus secretion, cough, and decreased HR w/ inspiration)

Pulmonary arteriole system runs adjacent to:

bronchial tree

Pulmonary venous system found distant from:

airways

Lymphatics found adjacent to both:

arteriole and venous systems

**remove fluid (especially near alveoli sac where pulmonary edema will occur)

**do not penetrate alveolar wall

The ability of the lungs to relate changes in volume to changes in pressure

compliance

Which dz has a problem with recoil?

Emphysema

What do pulmonary function tests do?

identify abnormalities in respiratory function and determine the extent of those abnormalities

Types of pulmonary function tests:

spirometry

air flow rates

calculation of lung volumes/capacities

Spirometry is ____ and measures ______.

Indirect; Air

**Used to re-inflate the lungs (especially after surgery)

Tidal volume

inhaled and exhaled air each normal breath

inspiratory reserve volume

the maximum amount of air inhaled above a normal TV

expiratory reserve volume

the maximum amount of air exhaled below a normal TV

residual volume

amount of air left in lungs after maximum exhalation

Vital capacity

IRV + TV + ERV

Total lung capacity

VC (IRV + TV + ERV) + RV

Force vital capacity

begins with an inhalation from FRC (functional residual capacity) to TLC (total lung capacity) followed by a forceful exhalation from TLC to FV

Forced expiratory volume in 1 second (FEV1)

amount of gas exhaled during the first second of the FCV maneuver

Normal FEV1/FCV ratio

80%

Diminished FEV1/FCV ratio in patients with:

obstructive lung disease

**cannot get air out as quickly (but normal lung volume); low FEV1 but normal FVC

Increased or normal FEV1/FCV ratio in patients with:

restrictive lung disease

**high FEV1 but low FVC (volume is restricted, but flow is more because recoil is faster)

Major categories of pulmonary defense:

1. nonspecific (clearance, secretions, cell or biochemical defenses)

2. chemical (antibody mediated, antigen presentation, cell mediated)

Oxygen in blood is either ________ or ________

bound to hemoglobin

dissolved in plasma

Oxygen content in the blood depends on:

1. arterial PO2 (pressure of air we breath in)

2. hemoglobin level

Tissue oxygen delivery depends on:

1. oxygen content in the blood (O2 saturation)

2. CO

What determines blood O2 saturation

how much o2 is in environment?

how much are we breathing?

is our airway open?

Determinants of CO

SV and HR

Determinants of stroke volume

preload, afterload, contractility

CO2 is carried in the blood as:

HCO3- (dissolved in plasma)

carbaminohemoglobin

CO2 is _____ soluble than O2

more

In pts with lung disease, energy requirements are _________ at rest

greater

**and increases dramatically w/ exercise

Two components of breathing

1. elasticity (recoil to get air out)

2. resistance (obstruction)

Which lung segments have the greatest perfusion?

gravity-dependent segments (ex. Zone III)

Exercise allows for more:

perfusion of the lungs (to allow for more oxygenation of blood)

The ratio of ventilation to perfusion is highest at the:

apex

What is the reason for most abnormalities in O2 and CO2 exchange?

V/Q mismatch

Normal V/Q ration

0.8

When the V/Q ratio is high, it means:

ventilation > perfusion (ex. PE, cardiac arrest)

**dead space ventilation

When the V/Q ratio is low, it means:

ventilation < perfusion (ex. CF, asthma, effusion)

**shunt perfusion

When can you not give contrast (V/Q scan > CT)?

renal failure, pregnancy, allergy

Tests for pulmonary emboli are done with:

nucelar medicine

Which muscles manage breathing?

diaphragm, abdominal muscles, and intercostal muscles

Breathing originates in:

brainstem (medulla)

Major driving force of breathing

CO2 levels

What causes spontaneous breathing

output signals of the phrenic nerve (diaphragm) and spinal nerves (intercostals/abdominal muscles)

Sensory input for breathing is through:

carotid bodies and aortic bodies (arterial oxygenation)

**increases ventilation w/ hypoxia

Integrated responses of breathing:

arterial pH changes affect PaCO²

Global Initiative for Chronic Obstructive Lung Disease (GOLD)

improve prevention and treatment of COPD worldwide

airflow limitation of COPD is usually ___________ and associated with _________________ to noxious particles or gases

progressive; an abnormal inflammatory response of the lungs

Gold 1: Mild

FEV1 > 80% predicted

FEV1/FVC < 0.7

Gold 2: Moderate

FEV1 is between 50-80%

FEV1/FVC < 0.7

Gold 3: Severe

FEV1 is between 30-50%

FEV1/FVC < 0.7

Gold 4: Very Severe

FEV1 < 30% predicted

FEV1/FVC < 0.7

Fundamental issue of obstructive lung disease:

resistance to airflow

What causes increased resistance to airflow

1. decreased lumen size (obstructive secretions - asthma/chronic bronchitis)

2. airway wall thickening/narrowing from inflammation or constriction (asthma/chronic bronchitis)

3. structures supporting airway (ex. elastic tissue destroyed in emphysema)

What is the difference between asthma and emphysema/chronic bronchitis?

asthma is reversible and emphysema/chronic bronchitis are not

Asthma can be caused by:

environmental factors or genetics

Asthma is a disease of airway ____________ and airflow _____________. Symptoms are ___________.

inflammation; obstruction

intermittent

Symptoms of asthma

wheezing, SOB, chest tightness, cough

Symptoms of asthma indicate:

bronchial hyper-responsiveness

What will release of mediators do?

alter airway smooth muscle tone/responsiveness

cause mucus hyper-secretion

damage airway epithelium

What is the most common chronic pulmonary disease?

asthma

Epidemiology of asthma

more common in men, African Americans, inner-city dwellers, and premature babies

Why are premature babies more at risk for asthma?

lungs are the last to develop

Intrinsic vs. Extrinsic asthma

Intrinsic asthma is NOT related to allergies, has later age of onset, and is often more severe

Extrinsic is related to allergy and IgE mediated, appears mostly in childhood, and is often mild

Physiologic or pharmacologic mediators that trigger asthm

Histamine, Methacholine, Adenosine triphosphate

Exogenous physiochemical agents that produce airway hyperactivity

exercise, pollutants, viral respiratory infections, propranolol, ASA/NSAIDs, cold air

Why you do not want to give beta blockers to asthmatics?

affects B2 (lungs) and causes bronchoconstriction

Asthma is often associated with what?

atopy (Type I)

Atopy

A hypersensitivity or allergic state (production of IgE antibodies in response to an allergy)

Status asthmaticus

a severe, life-threatening asthma attack that is refractory to usual treatment

**complete airway lumen obstruction

Common manifestations of atopy

allergic rhinitis

allergic asthma

atopic dermatitis (eczema)

What begins an asthma exacerbation?

Activation of local inflammatory cells, principally mast cells and eosinophils

What do the mediators cause?

smooth muscle contraction

mucus hypersecretion

vasodilation (with endothelial leakage and edema)

During an asthma exacerbation, some of the preformed & rapidly acting mediators recruit additional:

inflammatory cells (eosinophils and neutrophils)

What aids in perpetuating local airway inflammation and hyper-responsiveness?

cytokines and chemokines

What do mast cells do?

secrete histamine

Function of B cells in asthma pathogenesis

differentiate into IgE and IgA producing plasma cells

What drives tissue remodeling & submucosal airway fibrosis?

Production of growth factors and fibroblasts

**can cause fixed airway obstructino

Elements of a normal bronchus

thin layer of mucus on top

normal epithelial basement membrane

small smooth muscle layer

Elements of a asthmatic bronchus

thick mucus

epithelial basement

membrane makes goblet cells (makes more mucus) and have increased macrophages

increase size of smooth muscle layer

IgEs, mast cells, lymphocytes, neutrophils, and eosinophils are within the bronchus

What causes increased airflow resistance in asthmatic patients?

airway inflammation, smooth muscle hypersensitivity, and narrowing of airways

Which elements exacerbate airway obstruction?

mucus hypersecretion and bronchoconstrictor stimuli