Module 5 Flashcards
Ventilation
physiological process of breathing
Gas exchange
process of oxygen transport from lungs to tissue cells and carbon dioxide from tissue cells to lungs
How does gas exchange occur?
Diffusion across pressure gradients
Respiratory membrane
capillary membrane, basement membrane, alveolar wall
typically it is very thin
Anoxia
total depletion of oxygen in the tissues. will lead to cellular death
Hypoxia
depletion of oxygen levels in the tissues.
can be caused by impaired perfusion or low oxygen in arterial blood
Hypoxemia
reduced oxygen levels in arterial blood
Types of chemoreceptors
Central
Peripheral
Central Chemoreceptors
Located in the medulla oblongata of the brainstem
Monitor CO2 levels in cerebrospinal fluid
Peripheral Chemoreceptors
Located in the arch of the aorta + carotid bodies
Monitor O2 levels in cerebrospinal fluid
What stimulates breathing?
Indirectly: Carbon dioxide oxygen
Directly: Hydrogen ions
reduction in pH triggers breathing due to the carbonic anhydrase equation
Normal Inspiratory Muscles
Diaphragm
External Intercostal Muscles
Forced Expiratory Muscles
Abdominal Muscles (transverse, oblique) Internal Intercostal Muscles
Forced Inspiratory Muscles
Sternocleidomastoid
Scalene
Types of alveolar cells
Type 1 - provide surface area
Type 2 - produce surfactant
Macrophages - phagocytocize cellular debris
Anatomy of bronchial tree
Trachea + bronchi/larger bronchioles are smooth tissue with cartilagenous rings –> plates
Smaller bronchioles + alveoli = smooth muscle
Alveoli anatomy
Alveoli = singular sac
Alveolar septum = tissue that separates alveoli (contributes to surface area)
Alveolar sac = cluster of alveoli
Alveolar duct = continuous with respiratory bronchiole
Bronchial Tree
Major Bronchi (right/left) Lobar Bronchi Segmental Bronchi Bronchioles Terminal Bronchioles Respiratory Bronchioles
Two Respiratory Zones
Conducting -> move air
Respiratory -> participate in gas exchange
Conducting Zone
nose pharynx larynx trachea bronchi terminal bronchioles
Respiratory Zone
respiratory bronchioles
alveolar duct
alveoli
Methods of Oxygen transport
dissolved in plasma - 3%
bonded with heme in hemoglobin - 97%
Methods of Carbon Dioxide transport
dissolved in plasma - 7%
bonded with heme in hemoglobin - 20%
bicarbonate ions - %
Carbonic Anhydrase Equation
carbon dioxide diffuses across plasma membrane of red blood cells and enters cytosol
in cytosol CO2 + H2O –> H2CO3 (carbonic acid) –> H+ & HCO3 (bicarbonate)
Enzyme that catalyzes water and carbon dioxide
Carbonic anhydrase
Factors increasing oxygen affinity
low temperature
high pH
high partial pressure of oxygen
low partial pressure of carbon dioxide
Factors decreasing oxygen affinity
high temperature
low pH
low partial pressure of oxygen
high partial pressure of carbon dioxide
Atmospheric air
a combination of gases
70% Nitrogen
21% Oxygen
Water Vapor
Other gases
Pneumothorax
Collapsed lung
Occurs when there is a change in the intrapleural pressure
Anemia
a collection of disorders characterized by low red blood cells
Polycythemia
creation of new blood cells
What is Sp02
oxygen saturation
95-100%
measures the saturation of available hemoglobin
What is PaO2
partial pressure of oxygen in arterial blood
normally 80 mm Hg
measures amount of oxygen dissolved in blood plasma
4 Processes of Respiration
Alveolar Ventilation
Alveolar Perfusion
Alveolar-capillary diffusion
Gas transport in circulation
Factors impairing ventilation
Damage to CNS –> respiratory muscles require continuous innervation
Disorder to nasopharynx/lungs
Reduction in pulmonary/alveolar elasticity
Changes in atmospheric O2 (less O2 at higher altitudes)
Narrowed airways - inflammation, occlusion
Pulmonary edema
Right-sided Heart Failure
occurs due to increased pulmonary blood pressure
right ventricle has to work harder to pump blood which leads to ventricular hypertrophy
inefficient pumping of blood causes blood to backflow into vena cava causing peripheral edema
Pulmonary edema
caused by left-sided heart failure
trauma to chest
pneumonia
Pulmonary embolism
blockage in the pulmonary artery
usually caused by deep vein thrombosis in the legs
Clinical Manifestations of COPD
fatigue confusion high blood pressure high respiratory rate increased work of breathing hypoxia/hypoxemia hypercapnia --> acidosis cyanosis clubbing of nails due to prolonged hypoxia barrel chest (emphysema) productive cough asymmetric thorax
Normal Respiratory Rate
10-20 breaths/minute
Problem-Based History
cough dyspnea (shortness of breath) especially on exertion chest pain while breathing productive cough fatigue anxiety
Cues of Impaired Ventilation/Gas exchange
tripod position
anxiety
changes in mentation
Innervation of diaphragm
Phrenic Nerve - Cervical spine
Innervation of external intercostal muscles
Nerves originating from Thoracic spine
Lung Sounds
Stridor - bronchoconstriction
Rhonchi - blockages in airway
Crackles - fluid in lungs
Wheezes
Diagnostic Tests
Lab tests (arterial blood gases, complete blood count, sputum exam, skin test, pathologic)
Radiologic
Pulmonary Function Tests
Treatment
Oxygen Therapy Pulmonary respiratory community groups Rest therapy Respiratory muscle training Medication Nutrition therapy Diaphragmatic breathing Works simplification
Respiratory center
located in the medulla oblongata/pons
Dorsal Respiratory Center
controls rhythm of breathing
Ventral Respiratory Center
controls inhalation
Respiratory lobule
terminal bronchiole, alveolar duct, alveoli, pulmonary blood vessels + lymphatic vessels
Factors contributing to alveolar-capillary diffusion
surface area of alveoli
thinness of respiratory membrane
diffusion distance
pressure gradients
Parasympathetic Effects on Respiratory System
airway constriction
vasodilation
Sympathetic Effects on Respiratory System
airway dilation
vasoconstriction
Factors Affecting Lung Ventilation
Chest Wall Compliance
Lung Compliance
Lung Volumes and Capacities
Tidal Volume
Vital Capacity
Forced Expiratory volume
Factors Affecting Lung Compliance
elastin and collagen fibers
water content
surface tension (surfactant)
Forced Expiratory Capacity
75-85% of vital capacity in one second
maximum amount of air you can exhale in one second
Types of emphysema
Panacinar
Centriacinar
Causes of COPD
Smoking
Environmental pollutants (physical, chemical)
Genetic (lack of production of alpha-1 anti-trypsin)
Frequent childhood respiratory infections
Age
Hypercapnia
Elevated levels of CO2 in the blood
COPD Treatment
Rest therapy Oxygen therapy Diet (reduced carbohydrates) Respiratory muscle retraining Medication
Pack years
used to measure how much a person has smoked over time
Pack year equation
packs/day x years
OR
of cigarettes smoked per day/20 x years
(1 pack = 20 cigarettes)
What is PaCO2
35-45 mm HG normally
Ventilation Perfusion Ratio
Ventilation/Perfusion
can be affected by reduced ventilation or reduced perfusion
Ideally this number should be 1 for optimal function
Causes of hypoxemia
hypoventilation
mismatch between ventilation/perfusion
impaired perfusion
impaired ventilation
SpO2 of COPD patients
88-92%
COPD
chronic disease that causes obstruction to expiration
leads to hypoxemia and hypercapnia
includes two diseases: chronic bronchitis and emphysema
Chronic Bronchiits
inflammation of the airways hypertrophy of the mucus glands/goblet cells lead to an overproduction of mucus fibrosis of bronchiolar wall clogs the airway impeding ventilation V/Q mismatch --> hypoxemia, cyanosis chronic productive cough (sputum) repeated respiratory infections
Emphysema
destruction of elastic tissue distal to the terminal bronchioles
caused by elastase digesting elastin fibers –> weakens alveolar wall, alveolar duct, alveolar septum
reduces surface area/compliance of alveoli inhibiting ventilation
no V/Q mismatch
pursed light breathing
increased anteroposterior thorax (barrel chest)
increased work of breathing
Tidal Volume
amount of hear inhaled/exhaled in one breath
~500 mL
Forced Vital Capacity
maximal amount of air you can exhale after maximal inhalation
Residual volume
amount of air remaining in lungs following exhalation
Forced expiratory volume
amount of air you can exhale in 1 sec
should be 75-85% of expiratory reserve volume
What is lung compliance
lung compliance is the ability of the lungs to expand during inspiration
Three factors decreasing lung compliance
water content in alveoli (infection)
increased surface tension in lungs (reduced surfactant)
loss of elastin, collagen fibers
Factors affecting alveolar-capillary diffusion
surface area
concentration gradient of gases
diffusion distance (thinness of respiratory membrane, edema)
Consequences of impaired gas exchange
increased work of breathing
hypoxemia/hypercapnia
hypoxic cell injury
Compensatory Mechanisms
increased respiratory rate
polycythemia
increased heart rate –> increased blood pressure
redistribution of blood from peripheral extremities to core systems
Normal PaCO2
35-45 mm HG
Recommended nutrition for COPD patients
high calorie
high protein
smaller meals if dyspneic
