Exam 1 - Liu: Respiratory Pathophysiology

Pulmonary structures include

-airways (conducting and respiratory)-thoracic cage-lungs-blood vessels-nervous system

conducting airways

upper, low airways:-nasopharynx-oropharynx-larynx-trachea-bronchi-bronchioles (8-16)

respiratory airways

acini:-respiratory bronchioles (16-24)-alveolar ducts (26)

what are the primary gas-exchange units?**

alveoli

thoracic cage

-12 ribs-external/internal intercoastal muscles-diaphragm-pleural space (parietal pleura-visceral pleura)

lungs

3 lobes in right and 2 lobes in leftalveoli

vessels

pulmonary and bronchial circulations

nervous system

dorsal and ventral respiratory groups

primary function of the respiratory system

exchange of gases (O2 and CO2) based on alveolocapillary membrane

exchange processes include

ventilation and diffusion

Airway diagram

0

ventilation

mechanical movement of gas into and out of the lungs

successful ventilation depends on

-interaction of muscles (inspiration/expiration)-alveolar surface tension-elastic properties of lungs and chest wall-resistance to airways

ventilation is regulated by

neurochemical control

diffusion

the movement of gases between gas spaces in the lungs and the bloodstream

diffusion process

alveoli -> alveolar epithelium -> alveolar basement membrane -> interstitial space -> capillary basement membrane -> capillary endothelium -> red blood cells (Hb)

successful diffusion of O2 depends on**

-the alveolocapillary membrance-PO2-Hb content

Alveolocapillary Membrane: gas exchange

0

neurochemical control of respiration is performed by the

respiratory center in the medulla

the respiratory center in the medulla consists of

-dorsal respiratory group (DRG)-ventral respiratory group-pneumotaxic center-apneustic center

dorsal respiratory group (DRG) is the

dominant regulator (resting state, inspiration)

ventral respiratory group is responsible for

inspiration/expiration

Types of lung receptors

-irritant receptors-stretch receptors-J-receptors

irritant receptors

-sensitive to vapors, gases, and dusts-initiate coughing

irritant receptors are located in proximal larger airways but are absent in _____________

the distal airways (alveoli)

stretch receptors

sensitive to size and volume of lung

J-receptors

pulmonary capillary pressure

Chemoreceptors include

central and peripheral chemoreceptors

central chemoreceptors are very sensitive to

CSF pH and H+

peripheral chemoreceptors of the carotid and aortic bodies in arteries are sensitive to

oxygen levels in arterial blood

Common signs/symptoms or pulmonary disease

-cough-dyspnea-chest pain-abnormal sputum-hemoptysis-cyanosis-fever

the color, consistency, odor, and amount of sputum vary with different pulmonary disease and can be used to identify microorganisms and cancer cells

0

dyspnea

-subjective sensation of uncomfortable breaching, feeling of being unable to get enough air-can be caused by diffused and extensive pulmonary disease

signs of dyspnea

nostril flaring, intercostal and supracostal retractions

orthopnea

-difficult breath when a person is lying down-found in ascites (excessive water in abdominal cavity)

paroxysmal nocturnal dyspnea

-wake up at night for gasping-found in pulmonary edema (excessive fluid in lungs) caused by left ventricular failure

hypoventilation

inadequate alveolar ventilation in relation to metabolic demands

hypoventilation is caused by

reduced minute volume (tidal volume x respiratory rate) resulting in CO2 acculation

PCO2 > _________ mmHg in blood pas analysis is considered hypoventilation

PCO2 > 44 mmHg

hypoventilation can lead to

hypercapnia

Hypercapnia, secondary hypoexmia leads to

respiratory acidosis

cases of hypercapnia

-drugs depressing respiratory center-diseases or trauma in medulla-abnormalities in spinal cord-neuromuscular diseases (myasthenia gravis, muscular dystrophy)-airway obstruction (tumors, apnea)-increased physiological dead space (emphysema)

hyperventilation

alveolar ventilation exceeds metabolic demands; lung removes CO2 at a faster rate than it is produced.

PCO2 < _________ mmHg in blood gas analysis is considered hyperventilation

PCO2 < 36 mmHg

hyperventilation can lead to

hypocapnia

hypocapnia results in

respiratory alkalosis

hypocapnia commonly occurs with

-severe anxiety-acute head injury-acute asthma

hypo and hyperventilation gas exchange chart

0

A cough is an important reflex that

cleans the airways of large amounts of inhaled material, excessive secretions or abnormal substances (sputum)

Cough is initiated in the larynx and tracheobronchial tree by __________________ stimulation (larynx, tracheobronchial tree)

irritant receptor

other than the larynx and tracheobronchial tree, cough receptors are also located in

-external auditory canal-diaphragm-pericardium-pleura -stomach

an acute cough is one that lasts

<2~3 weeks

a acute cough can be the result of

-upper respiratory infection-allergic rhinitis-acute bronchitis-pneumonia-congestive heart failure-pulmonary embolus

a chronic cough is one that perists for

> 3 weeks

in nonsmokers a chronic cough can be caused by

-postnasal drainage syndrome-asthma-gastroesophageal reflux disease-ACE inhibitors

in smokers a chronic cough can be caused by

-chronic bronchitis -ACE inhibitors (lisinopril, captopril)-lung cancer should be considered

Hypoxemia

reduced oxygenation of arterial blood caused by respiratory alterations (PaO2< 50 mmHg)

What is a normal PaO2?

80-100 mmHg

what PaO2 is considered hypoxemia?

< 50 mmHg

hypoxemia can be caused by

-decreased oxygen content of inspired gas -hypoventilation-diffusion abnormalities-abnormal ventilation-perfusion ratio-pulmonary right-to-left shunt

Hypoxia

reduced oxygenation of cells in tissues

causes of hypoxia

-Low cardiac output-cyanide poisoning -carbon monoxide poisoning-alterations of other systems

Alveolocapillary diffusion abnormalities can be caused by

-emphysema-fibrosis-edema

what is the most common cause of hypoxemia?

abnormal ventilation-perfusion ratio (V/Q)

what is a normal ventilation-perfusion ratio (V/Q)

0.82

what can alter ventilation-perfusion ratio (V/Q) and ultimately lead to hypoxemia?

-asthma-chronic bronchitis-pneumonia -acute respiratory distress syndrome (ARDS)

Hypoxic pulmonary vasoconstriction can contribute to _____________________ and _________________________

pulmonary hypertension and right heart failure

cyanosis

bluish discoloration of the skin and mucous membrane

cyanosis usually develops when desaturated Hb __________ g/dl

>5 g/dl

cyanosis can be caused by

-decreased arterial oxygenation-pulmonary/cardiac right-to-left shunts-decreased cardiac output-cold environment-anxiety

cyanosis is an ____________ indicator of hypoxemia for respiratory diseases

insensitive

central cyanosis affects the

buccal mucous membranes, lips

peripheral cyanosis affects the

nail beds

can cyanosis be the sole indicator for hypoxemia?

NO, arterial PaO2 should be measured by blood gas analysis for hypoxemia

clubbing

the selective bulbous enlargement of the end (distal segment) of a digit (finger or toe)

clubbing is associated with diseases that interfere oxygenation, such as

-bronchiectasis-cystic fibrosis-pulmonary fibrosis-lung cancer-lung abscess-congenital heart disease

Pulmonary Edema

fluid in the lungs

normal alveoli area) dryb) moist

dry and contain little fluid

how is the lung kept dry?

-lymphatic drainage-a balance among capillary hydrostatic pressure, capillary oncotic pressure, capillary permeability, alveoli oncotic pressure (interstitial space).-surfactant lining the alveoli repels water out of alveoli

predisposing factors for pulmonary edema include

-heart disease-acute respiratory distress syndrome (ARDS)-inhalation of toxic gases

decreasing gas exchange during pulmonary edema is caused by

decreased surfactant and diffusion

manifestation of pulmonary edema

-dyspnea-paroxysmal nocturnal dyspnea (PND)-hypoxemia-increased work of breathing

the most common cause of pulmonary edema is

heart disease

_______ always causes pulmonary edema

ARDS

causes of pulmonary edema chart

0

Acute respiratory distress syndrome (ARDS)

fulminant respiratory failure, characterized in acute lung inflammation and diffuse alveolocapillary injury, and refractory hypoxemia

Predisposing factors for Acute respiratory distress syndrome (ARDS)

-sepsis-multiple trauma-pneumonia (staphylococcus aureus) -burn-pancreatitis-disseminated intravascular coagulation (DIC)

pathophysiology of ARDS

-pulmonary edema injures alveolocapillary membrane (alveolar epithelial; endothelial) -increased capillary permeability-alveolar consolidation-hyaline membrane

causes of ARDS

-neutrophils-macrophages-complement-endotoxin-interleukin-1-tumor necrosis factor-α-other inflaming factors

clinical course of ARDS

hyperventilation → respiratory alkalosis → dyspnea, hypoxemia → metabolic acidosis → respiratory acidosis → further hypoxemia → hypotension, ↓cardiac output → multi-organ dysfunctions → death

lying on your ___________ improves breathing if you have COVID

stomach

Obstructive pulmonary diseases are aharacterized by airway obstruction that is worse with

expiration

unifying symptoms of obstructive pulmonary diseases

-wheezing-dyspnea-decreased forced expiratory volume in one second (FEV1) in spirometry

common obstructive pulmonary diseases

-asthma -chronic bronchitis -emphysema

asthma quick summary

inflammation + hyper-responsiveness → bronchospasm; genetic background

chronic bronchitis

-(3 months in 2 yr)-mucus hypersecretion-productive cough-smoking history

emphysema

-permanent enlargement of gas exchange airways with destruction of alveolar wall-commonly comes from chronic bronchitis or asthma

Asthma is a chronic disorder of the airways that involves a complex interaction of

airway obstruction, bronchial hyper-responsiveness, and an underlying inflammation

inflammatory elements that contribute to asthma include

-IL-4-IgE-mast cells -inflammatory mediators (histamine, leukotrienes)-acetylcholine-smooth muscle constriction-mucus secretion

Asthma occurs at all ages, but more than half of all cases develop in ____________ or before age ____________

children; 40

Asthma is a familial disorderA) trueB) false

true

___________ (disintegrin and metalloprotease) is particularly associated with asthma and bronchial hyper-responsiveness

ADAM33

risk factors for asthma

-Allergen exposure-urban residence-exposure to air pollution-cigarette smoke-respiratory infections -obesity

asthma chart

0

acute asthma attack

-chest constriction-expiratory wheezing-dyspnea-nonproductive coughing-prolonged expiration-tachycardia-tachypnea