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