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Nu Patho Study Guide Unit 5 fully solved rated A+
- Course
- NU 545
- Institution
- University Of South Alabama
Nu Patho Study Guide Unit 5 fully solved rated A+
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Nu Patho Study Guide Unit 5Know type I and Type II alveolar cells (pg 1229) - correct answer ✔✔The alveolar septa consist of an
epithelial layer in a thin, elastic basement membrane but no muscle layer. Two major types of epithelial
cells appear in the alveolus. Type I Alveolar cells provide structure, and type II Alvoelar cells secrete
surfactant, a lipoprotein that coats the inner surface of the alveolus and facilitates its expansion during
inspiration, lowers alveolar surface tension at end-expiration, and prevents lung collapse. Surfactant also
contributes to control of lung inflammation and innate and adaptive immunity.
Role of surfactant in the lungs-infants and adults (Pg 1235, 1256, 1292) - correct answer ✔✔• Alveolar
ventilation, or distention, is made possible by surfactant, which lowers the surface tension by coating the
air liquid interface in the alveoli. Surfactant, a lipoprotein produced by type II alveolar cells, includes two
groups of surfactant proteins. Surfactant lines at Alveolar side of the Alveolocapillary membrane and in
effect reverses Laplace's law (pg 1235).
• The decrease in surface tension caused by surfactant also is responsible for keeping the alveoli free of
fluid. If surfactant production is disrupted or surfactant is not produce in adequate qualities, alveolar
surface tension increases, causing alveolar collapse, decreased lung expansion, increased work of
breathing, and severe gas exchange abnormalities.
• In the absence of surfactant the surface tension tends to attract fluid into the alveoli. Surfactant
participates in host defense against respiratory pathogens.
• Atelectasis-Is the collapse of lung tissue. There are three types of atelectasis: Compression, absorption,
and surfactant impairment.
o Surfactant impairment results from decreased production or inactivation of surfactant, which is
necessary to reduce surface tension in the alveoli and thus prevent lung collapsed during expiration.
Surfactant impairment can occur because of premature birth, and acute respiratory distress syndrome,
anesthesia, or mechanical ventilation. (pg 1256)
o Pediatrics: surfactant is critical for maintaining alveolar expansion thus allowing normal gas exchange
reduces surface tension, prevents alveolar collapse at the end of each exhalation. Without surfactant the
alveoli tend to stay closed, demanding greater inspiratory force and work of breathing to re-expand on
next breath. Deficiency of surfactant is often seen in premature infants and causes respiratory distress
syndrome (RDS), also known as hyaline dis
Know Chronic Bronchitis-pathophysiology, etiology, prevention, clinical manifestations, treatment,
complications (Pg 1267) - correct answer ✔✔• Chronic bronchitis is defined as hypersecretion of mucus
and chronic productive cough that continues for at least 3 months of the year (usually the winter
months) for at least two consecutive years. Inspired irritants result in airway inflammation with
,infiltration of neutrophils, macrophages, and lymphocytes into the bronchial wall. Initially chronic
bronchitis affects only the larger bronchi, but eventually all airways are involved. The thick mucus and
hypertrophied bronchial smooth muscle narrow the airways and lead to obstruction, particularly during
expiration when the airwaves are constricted. Obstruction leads to ventilation perfusion mismatch with
hypoxemia. The airways collapsed early an expiration trapping gas in the distal portions of the lung. This
leads to decreased title volume, hypoventilation, in hypercapnia.
• Clinical= Common symptoms include decreased exercise tolerance, wheezing, and shortness of breath.
Individuals have a productive cough "Smokers cough", An evidence of airway instruction is shown by
spirometry. As disease progresses copious amounts of sputum or produced accompanied by frequent
pulmonary infections. Mark hypoxemia leads to polycythemia (overproduction of erythrocytes) and
cyanosis. If not reversed hypoxemia leads to pulmonary hypertension and eventually results in cor
pulmonale and can lead to severe disability or death.
• Evaluation and treatment= Diagnosis is based on history of symptoms, physical examination, chest x-
ray, PFTs and blood gas analysis; tests reflect progressive nature of the disease. Prevention of chronic
bronchitis is the best treatment because pathologic changes are not reversible. By the time an individual
seeks medical care for symptoms, considerable airway damages are present. If the individual stops
smoking, disease progression can be halted.
o Bronchodila
Know gas exchange in the lungs (pg 1229) - correct answer ✔✔• The bronchioles terminate in gas
exchange airways, where oxygen enters the blood and carbon dioxide is removed from it. The gas
exchange airways consist of respiratory bronchioles, alveolar ducts, and alveoli.These structures together
or sometimes called the acinus, and all of them participate in gas exchange.
o The alveoli are the primary gas exchange units of the lungs, where oxygen enters the blood and CO2 is
removed. Tiny passages called pores of Kohn permit some air to pass through the septa from alveolus to
alveolus, promoting collateral ventilation and even distribution of air among the alveoli. The lungs
contain approximately 50 million alveoli at birth and about 480 million by adulthood.
How is the patient's alveolar ventilation measured? (pg 1232) - correct answer ✔✔• The adequacy of
alveolar ventilation cannot be accurately determined by observation of ventilatory rate, pattern, or
effort. An arterial blood gas analysis must be performed to measure Paco2 (arterial CO2).
Know asthma (adult and childhood)- pathophysiology, etiology, prevention, inflammatory mediators,
clinical manifestations, treatment (acute and chronic), complications (Pg 1263 & 1308) - correct answer
✔✔• Asthma in Children is the most prevalent chronic disease in childhood affecting about 10% of US
children between age 5 and 17 years old, with boys more often affected than girls. Prevalence is
increasing among non-Hispanic blacks, obese children, and children from urban and low income
populations. Environmental factors and genetic susceptibility play a role.
, • Patho: Asthma is initiated by a type I hypersensitivity reaction primarily mediated by IgE, which is same
for adults. Inflammation, bronchial spasm, and mucus production in the airways lead to ventilation and
perfusion mismatch with hypoxemia and expiratory airway obstruction with air trapping and increase
work of breathing. In young children, airway obstruction can be more severe because of smaller
diameter of their airways.
• Clinical: In a typical acute asthma attack and children, the major complaints of coughing, wheezing,
and shortness of breath. About 70 to 80% of acute wheezing episodes are associated with viral
respiratory tract infections. There may be signs of preceding URI, such as rhinorrhea or low-grade fever.
In infants and toddlers younger than 2 years old, the most common of these is RSV. In older children and
adults the major viral trigger is rhinovirus.
o Expiratory wheezing is often described as high-pitched and musical, along with prolongation of the
expiratory phase of the respiratory cycle. Breath sounds may become faint when air movement is poor.
Sometimes barrel chest is visible, respiratory and heart rates are elevated, Nasal flaring and accessory
muscles use are evident with retractions. Infants may be seen "head bobbing" because of
sternocleidomastoid muscle use. The child may appear anxious or diaphoretic, important signs of
respiratory compromise. The child may speak in clip sentences or not at all because of dyspnea. Findings
of a
Asthma in Adult - correct answer ✔✔• Asthma in Adults is a chronic inflammatory this disorder of the
bronchial mucosa that causes bronchial hyperresponsiveness, constriction of the airways, and variable
air flow obstruction that is reversible. Asthma occurs in all ages, half of cases developing during
childhood and another third before age 40. Estimated 24.6 million people have asthma, highest for adult
female, black persons and adults older than 65. Asthma is most commonly if the Milio disorder and milk
more often hundred jeans have been identified that may play a role in the susceptibility and
pathogenesis of asthma, including those that influence the production of IL-4, IL-5, and IL-13; IgE;
eosinophils, and others (pg 1263). Exposure to high levels of certain allergens during childhood increases
the risk for asthma. Furthermore, decreased exposure to certain infectious organisms appears to create
immunologic imbalance that favors the development of allergy and asthma in some individuals. This
complex relationship has been called the hygiene hypothesis.
• Patho: During early asthmatic response, antigen exposure to the bronchial mucosa activates dendritic
cells (antigen presenting cells) to present the antigen CD4+T cells, which differentiate into Th2 cells.
These Th2 cells released numerous cytokines. Together these mediators cause vasodilation, increased
capillary permeability, mucosal edema, brochial smooth muscle contraction (Bronchial spasm), and
tenacious mucus secretion from mucosal goblet cells with narrowing of the airways and obstruction to
airflow. The late asthmatic response usually begins 4-8 hours after the early response. Eosinophil
mediators cause direct tissue injury with fibroblast proliferation and airway scarring. Airway obstruction
increases resistance to airflow and decreases flow rates, especially expiratory flow. Respiratory ac
Ageing and the pulmonary system (pg 1244-1245) - correct answer ✔✔• Normal alterations include: loss
of elastic recoil, stiffening of the chest wall, changes in gas exchange and increases in flow resistance.
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