Respiratory System Flashcards
Resp System primary function
Gas exchange
- provide O2 for metabolism in the tissue
- remove CO2, the waste product of metabolism
3 step process of Resp System
Ventilation
- mechanical movement of air in and out of lungs
Diffusion
- move gas between lung and blood
Perfusion
- move blood from lung capillary to tissues
Chest wall and pleura
Visceral pleura
- membrane covers the lungs
Parietal pleura
- membrane lines the thoracic cavity
Pleural space
- between visceral and parietal pleurae
- contains lubricating fluid for membranes to slide against each other
- negative pressure
Bronchi
Have epithelial lining
Exocrine glands
- goblet cells: produce mucus
- ciliated cells: move secretions toward pharynx
Alveoli
Functional unit of the lung
Exchange of CO2 and O2
- epithelial cells: provide structure and surfactant
- surfactant: lipoprotein that lowers alveolar surface tension to keep lung expanded at end-expiration; produced at 26-27th week gestation
Pulmonary Circulation
Delivers nutrients to lung tissue
Provides O2 and CO2 for gas exchange
Lower pressure/resistance than systemic circulation
Pulmonary artery:
- divides into arterioles then capillaries
Alveolar membrane: thin membrane where gas exchange occurs
- changes in thickness of this membrane impairs gas exchange.
Pulmonary vein:
- drains the capillaries that are filled with oxygenated blood
Oxygen transport
- Diffuses across alveolar-capillary membrane
- Binds to hemoglobin
- Hemoglobin carries 98%-99% O2 in blood (oxyhemoglobin)
- Oxygen dissociates from hemoglobin for use by cells
Carbon dioxide transport
3 ways:
1. Dissolved in plasma as PCO2
2. Attached to hemoglobin as carbonic acid
3. As bicarbonate HCO3
More soluble than O2 and diffuses quicker
Respiration
Exchange of oxygen and carbon dioxide during cellular metabolism
Respiration Rate
Ventilators rate, breaths per min
Tidal Volume
Volume of air per breath (400-800mL/breath)
Effective ventilation (minute ventilation) = RR x tidal volume
Chest wall restrictions
Decrease tidal volume and inc RR
Can progress to hypercapnia
Pneumothorax
Air/gas in pleural space —> destroys negative pressure —> lung collapses
Primary: spontaneous, rupture of blob
Secondary: chest trauma to pleura and rupture of belt with patient with emphysema
Open pneumothorax
Pressure in pleural space = atmospheric pressure
Air enters with inspiration, leaves with expiration
Tension Pneumothorax
Pressure in pleural space > atmospheric pressure
- air enters with inspiration but cannot leave one way valve
- displaces heart/vessels to cause mediastinal shift
- life threatening
Pleural Effusion and types
Collection of fluid in the pleural space
- Transudative (watery) - HF, Dec oncotic pressure
- Exudative ( WBC, proteins) - infection
- Pus (emphysema) - pneumonia, lung abscess
- Blood (hemothorax) - damage to blood vessels
- Chyle (milky; chylothorax) - damage to lymphatic vessels
Chest tube
Returns negative pressure to pleural space
Removes fluid or air
Pleuritis/pleurisy
Inflammation of the parietal pleura
- sharp, localized pain with deep breathing
- infection or pulmonary embolus
- analgesics, NSAID, anti-tussants
Pneumonia
Infection of the lower respiratory tract
Caused by bacteria, viruses, fungi, Protozoa, or parasites leading to inflammation, increased neutrophils and macrophages.
Edema from the inflammation stiffens the lung and Dec compliance and vital capacity
Manifestations:
- fever, chills, cough, dyspnea, hemoptysis, inspiratory crackles, rhonchi, and wheezing
Tuberculosis
Inhalation of bacteria —> lung inflammation —> alveolar machrophanges and neutrophils seal off bacterial colonies —> tubercles —> death of tissue inside tubercle —> growth of scar tissue around tubercle
Disease is dormant (latent TB) but reactivate if immune system is impaired (active TB)
Mycobacterium tubercle
S/S:
- weight loss, hemoptysis, anorexia, night sweats, cough
Tx:
- antibiotics (4 types)
- doses multiple times a day for 6-9 months
Restrictive lung disease
Lungs “restricted” from fully expanding
- atelectasis
- pulmonary edema
- acute respiratory distress syndrome (ARDS)
Obstructive lung diseases
Airway obstruction that is worse with exhalation; difficulty exhaling all air out of the lungs
- asthma
- chronic obstructive pulmonary disease
- cystic fibrosis
Atelectasis
Collapse of alveoli, due to external pressure, hypoventilated alveoli, or lack of surfactant
S/S: tachypnea, cough, leukocytosis, Dec lung sound
Common complication of surgery
Obstructive or nonobstructive
Pulmonary Edema
Excess water in the lungs due to poor lymphatic drainage, increased capillary hydrostatic pressure, and increased capillary permeability
S/S: dyspnea, crackles, VQ mismatch, hypoxemia, frothy pink sputum, hypercapnia
Tx: diuretics and vasodilators, oxygen
Acute Respiratory Distress Syndrome
Massive pulmonary inflammation that injures the alveoli capillary membrane and produces severe pulmonary edema
Macrophages and neutrophils activated in response to inflammation and infection, alveoli capillary membrane increases permeability so fluids, proteins, and blood cells leak from capillaries into alveoli and interstitium
S/S: rapid onset, severe dyspnea, hypoxemia, pulmonary infiltrates
Tx: prevent infection, oxygen, surfactant, and corticosteroids
Asthma
Inspiratory and expiratory wheezes
A chronic pulmonary disease causing bronchospasms and inflammation
- acute bronchospasms: intense breathlessness, coughing
- bronchoconstrict: histamine secretion, inc mucus and edema in airway
Cause: triggers
Treatment:
Quick relief
- short acting Beta agonist (albuterol)
- anticholinergics (ipratropium)
- systemic corticosteroids (prednisone)
Long term relief
- inhaled corticosteroids (beclomethasone)
- mast cell stabilizers (cromolyn)
- leukotriene modifiers (monteluekast)
- long acting beta agonist (salmeterol)
- methylxanthines (theophylline)
- immunomodulators (monoclonal antibodies)
COPD
Inflammatory response of lungs to noxious particles or gases
Limits airflow
Irreversible
Two types:
- chronic bronchitis
- emphysema
Medications:
- bronchodilators
- xanthines (phyliine)
- expectorants (guaifenesin for chronic bronchitis)
- antibiotics
- corticosteroids (last resort)
- oxygen
Chronic bronchitis
Hypersecretion of mucus + chronic productive cough for more than 3 months
Air trapping in the alveoli
Expiratory wheezes and crackles
Inspired irritant leads to immune response creating thick tenacious mucus
Emphysema
Permanent enlargement of gas-exchange airways with destruction of alveolar walls
Loss of lung elasticity and recoil
Hyperinflation of alveoli
Difficulty exhaling all air (hypercapnia)
Cystic fibrosis
Autosomal recessive inherited disease affecting chloride channels of epithelial cells of pancreas, airways, bile ducts, sweat glands, vas deferens
Patho:
- mucus plugging (inc goblet cells)
- chronic inflammation (inc neutrophils)
- chronic infection
S/S:
- persistent cough, steatorrhea, barrel chest, clubbing
Tx:
- bronchodilators, inhaled or IV antibiotics, pancreatic enzymes, and chest physiotherapy
Pulmonary Emboli
Occlusion of a portion of the pulmonary vascular bed by an embolus
S/S: sudden onset chest pain, dyspnea, tachypnea, tachycardia
Tx:
Heparin anti thrombotic if life threatening
