Respiratory System Introduction Flashcards
Conductive system
Nasal cavity, pharynx, larynx and bronchi
Pseudostratified columnar or ciliated columnar
Secretory goblet and serous cells
Function of the conductive system
Produce mucus layer to trap larger particles
Transitional system
Bronchioles (no cartilage or glands)
Clara cells (detoxification of xenobiotics and produce surfactant)
Function of the transitional system
Transition between the conductive and gas exchange systems
Gas exchange system
Alveoli
Type 1 pneumocytes: gas exchange
Type 2 pneumocytes: proliferative ability, maintain alveolar fluid balance, produce surfactant, metabolize xenobiotics
Function of the bronchi and bronchioles
Anti-inflammatory and microbial products
Mucocilary apparatus
Metabolization and surfactant production
Function of the alveoli
Gas exchange and surfactant production
Lung
Rapid gas exchange (in alveolus)
Ciliated cells
Expels mucus, inhaled particles and microbes by ciliary action
Mucus
Traps inhaled particles and microbes, neutralize soluble gases
Surfactant
Protects alveolar walls and enhances phagocytosis
Lysozymes
Antimicrobial enzyme
Abs
Prevents microbial attachment to cell membranes
Opsonization (bacteria rendered more susceptible to phagocytosis)
Transferrin and lactoferrin
Suppression of bacterial growth
Alveolar macrophage
Phagocytosis, main line of defense against inhaled particles and microbes
Inflammation
Rhinitis (inflamm of the nasal mucosa)
Sinusitis (inflamm of the sinuses)
Occur together: rhinosinusitis with nasal discharge
Serous rhinitis
Mildest form
Hyperemia of mucosa
↑ production of clear fluid
What is serous rhnitis caused by?
Mild irritants or cold air, early stages of viral infection or mild allergic reactions
Catarrhal Rhinitis
More severe than serous
Secretion of serous substance mixed with mucus
Mucus of catarrhal rhinitis
Due to↑ goblet cell activity
Thick, translucent or slightly turbid exudate
Leukocytes and cells debris
Suppurative rhinitis
From serve injury, associated with mucosal necrosis and secondary bacterial infections
Neutrophilic exudate (thick, opaque from white to green)
Fibrinous rhinitis
When nasal injury causes a severe ↑ in vascular permeability
Yellow, tan or grey rubbery mat on nasal mucosa
Types of fibrinous rhinitis
Diphtheritic: removal = ulcerated mucosa
Pseudodiptheritic: removal= mucosa intact
Granulomatous rhinitis
Infiltration of macrophages, lymphocytes and plasma cells int he mucosa and submucosa
Assoc with systemic fungal diseases, tuberculosis or FB
Granulomatous rhinitis may lead to the formation of _____________
Polyp
What bacteria causes granulomatous rhinitis?
Rhinosporidium seeberi
Sinusitis
Secondary to septic wounds, improper dehorning or tooth infections
Chronic sinusitis may lead to…
Osteomyelitis or extend through the bone causing meningitis or encephalitis
Classification of pneumonia
Bronchopneumonia (bacteria)
Interstitial (virus)
Embolic (bacteria or tumor)
Granulomatous (fungal)
Verminous (parasitic)
Bronchopneumonia
Firm/ hard texture
Cranioventral distribution
Initial injury on mucosa of bronchioles → deep alveoli or up to bronchi
CS of Bronchopneumonia
Inflammatory cells
Necrotic cell debris
Edema and hemorrhage within airways
What causes Bronchopneumonia?
Bacteria via inhalation
Manheimia haemolytica, histophilus somni, actinobacillus pleuropneomiae, mycoplasma
Interstitial Pneumonia
Rubbery/ elastic texture
Diffuse distribution
Result of hematogenous agents (aerogenous injury, virus, toxic gases)
Complicated by secondary bacterial pneumonia
CS of interstitial pneumonia
Chronic form results in alveolar fibrosis, hyperplasia of type 2 pneumocytes and lymphocytic inflammation
Where does interstitial pneumonia injury take place?
Any layer of the alveolar walls and the bronchiolar interstitium
Granulomatous pneumonia
Locally to multi focally extensive and nodular
Central necrosis +/- mineralization
Fungal etiology, entry aerogenous or hematogenous
What’s significant about the agents causing granulomatous pneumonia
Resistant to killing by phagocytic cells
Cryptococcus, coccidiodes, histoplasma and blastomyces with mycobactrium and rhodococcus
Embolic pneumonia
Widespread and multifocal distribution
Abscesses common sequelae
Common source: valvular endocarditis (right side of heart)
Metastatic neoplasia embolic
Verminous pneumonia
Caudodorsal distribution
Gritty/ granular texture
Mineralization
