病理学-呼吸系统疾病

• Alveoli type II cells 5% of the surface producing surfactant, lowering the surface tension Involved in the repair of alveolar epithelium
• Capillary network 85%~95% of the surface Arranged ideally for gas exchange
Mononuclear interstitial infiltrates viral and other atypical pneumonias
Granulomas and cavitation chronic pneumonias
Acute Bacterial Pneumonias
Lobar pneumonia Consolidation of an entire lobe
Right bronchus diverging at a lesser angle, foreign material more frequently aspirated Lobar, segmental, lobular
1. Bronchial tree (通气） conducting portion from main bronchi to terminal bronchioles
Deep and superficial network draining to the hilum lymph nodes
No lymphatics in most alveolar walls
Defense mechanisms
Location
Host Defense Mechanism
Upper Airways Nasopharynx Oropharynx
2. Submucosal gland serous and mucus 3. Wall smooth muscle contractile
elastic fibers, provide flexibility cartilage plate, for support
Bronchioles Φ < 1mm
Diseases of Respiratory System
呼吸系统疾病
Aantomy and Function
• Upper respiratory tract
nasopharynx(鼻咽), larynx(喉)
• Lower respiratory tract
trachea(气管), bronchi(支气管)
2. Terminal lung unit (gas exchange) respiratory portion from respiratory bronchiole to alveoli
Bronchial tree
1. Mucosa pseudostratified ciliated column cell goblet cell, producing mucus basal cell-stem cell small granules cell highly specialized bronchial lining cells, containing neurosecretory granules
1. Mucosa ciliated epithelial cell Clara cell (non-ciliated secretory cell)
2. Wall smooth muscle no gland no cartilage
Respiratory membrane
• Alveoli type I cells 95% of the surface gas permeable
Pathology and clinical features
A rather clear cut 4 staged battle in the affected lung in a period about 7-8 days
A complete and unsloppy recovery
Four stages a. Congestion b. Red hepatization c. Gray hepatization d. Resolution
Lobular pneumonia (Bronchopneumonia) Scattered solid foci in the same or several lobes
Lobar Pneumonia
Contiguous airspaces of part or all of a lobe are homogeneously filled with an exudate that can be visulized on radiographs as a lobar or segmental consolidation.
2. All blood from the body will pass through the lung and the biological pathogens (e.g bacterial, neoplasmic) embolus etc. can be trapped in the lung.
Lung defense mechanHale Waihona Puke Baidusms
Remarks
1. Respiratory system is communicating with external enviroment, from which pathogens, noxious gas or particles,so it is susceptible to the diseases.
Pulmonary vasculature
Double blood supply, protecting from ischemia Pulmonary circulation: functional Bronchial system: nutrient
Pulmonary lymph circulation
A disease of acute exudative inflammation
Pathogenesis
Healthy adult Host defenses depressed Normal inhabitants of the oropharynx and
Nasopharynx, Pneumococcus Aspiration of pharyngeal flora Lower lobes or the right middle lobe most frequently involved
Conducing Airways Trachea, bronchi
Lower Respiratory Tract Terminal airways, alveoli
Cough, epiglottic reflexes Sharp-angled branching of airways Mucociliary apparatus Immunoglobulin production(IgG, IgM, IgA)
Red hepatization (3-4d)
Gross A liver-like consistency A fibrinous or fibrinopurulent exudate of pleura
LM Intra-alveolar hemorrhage Massive neutrophils Fibrin packing within alveolar spaces Numerus pneumococci detected
Clinical feature Hemoptysis (rusty) Chest radiograph: a solid appearance extending to entire lobes or segments Dyspnea, debility, chest pain
Gray hepatization (4-6d)
Nasal hair Turbinates Mucociliary apparatus IgA secretion Saliva Sloughing of epithelial cells Local complement production Interference from resident flora
Congestion (1-2d)
Gross Heavy, red, boggy LM Vascular congestion
Proteinaceous fluid containing numerous pneumococci filling the alveoli Scattered neutrophils Clinical feature Acute, fever, chill Crepitation, moist rale Chest radiograph dim, uniform shadow
Pneumonia can be very broadly defined as any infection in the lung
Acute, fulminant or chronic Histologic spectrum
Fibrinopurulent alveolar exudate acute bacterial pneumonias
Alveolar lining fluid(surfactant, immunoglobulin, complement, fibronectin)
Cytokines(IL-1, TNF) Alveolar macrophages Polymorphonuclear leukocytes Cell-mediated immunity
Remarks
3. The lung is closely related to the heart, not only by their location but also by the pulmonary circulation.
4. Damage and disturbance to the specialized structures and function of the lung will lead to the development of the diseases specific to the lung. (e.g damage to the wall of bronchial tree, obstruction of bronchioles and disintegration of alveolar/capillary membrane)
“A turning point”
Gross Dry, gray, firm, granular
silicosis
I. Pneumonia 肺炎
Pulmonary infections
1/6 of all deaths in the U.S.A
Causes
Epithelial surface exposed to contaminated air Nasopharyngeal flora aspirated during sleep Lung parenchyma vulnerable to virulent organisms Defects in innate immunity and humoral immunodeficiency Cell-mediated immune defects Lifestyle factors (eg. cigarette smoke, alcohol) caused Facilitating infections