Pathophysiology Pulmonary Flashcards
Explain the larynx
Connects upper and lower respiratory tracts
Includes epiglottis, thyroid, cricoid cartilages, plus a few other small cartilages
What makes up the upper respiratory tract?
Nasal cavity (mucosal lining warms and humidifies the air) Pharynx (nasopharynx, oropharynx, and laryngopharynx)
What makes up the ACINUS? What occurs in the acinus?
respiratory bronchiole, alveolar ducts, alveoli
-gas exchange
What does the pulmonary tree (lower respiratory tract) divide into?
terminal bronchiole (conducting zone) and respiratory bronchioles (respiratory zone) –>acinus
What are the non-respiratory functions of the pulmonary system?
Phonation Acid-Base balance Pulmonary defense mechanisms Metabolic function of pulmonary system Filtration and removal of particles/microorganisms
Describe acid-base balance
Participates in acid-base regulation & compensation by removing CO2 from the blood stream
Describe pulmonary defense mechanisms
Air conditioning: optimal air temp & humidity for the body
Ventilation: warms/humidifies colder ambient air
Mucosa of nasal and oral cavities rich blood supply to warm/humidify air as it passes through to tracheal tree
Olfaction: sniffling–allows olfactory nerves to detect dangerous gas/material without bringing air into the lungs
List metabolic examples of pulmonary system
Prostaglandins (E and F) are removed Leukotrines--removed Serotonin--85-95% removed Norepinephrine--30% removed Epinephrine is not affeted Bradykinin--80% inactivated Angiotensin I--lungs produce ACE to converse Angio1-->AngioII ATP and AMP--40-90% removed
What are two mechanisms of filtration and removal of particles/microorganisms from reaching distal end of tracheal tree?
- Particles are trapped in mucous sheath lining the tubules
2. Particles are removed by ciliary action and reflex mechanisms
List steps of ciliary action (mucociliary escalator)
- tracheobronchial secretions and mucociliary transport
- lining of respiratory tract produces mucous
- mucous propelled AWAY from alveoli via cilia
- particles become trapped in the mucous and are transported to pharynx
- coughing forcefully propels mucous to pharynx
- mucous removed via swallowing, blowing nose
What do irritant receptors do? (Located in the airways)
produce SNEEZE (receptors = nasopharynx) produce COUGH (receptors = trachea)
How are the airways FUNCTIONALLY DIVIDED?
Into 2 regions:
conducting zone
respiratory zone
What is the anatomy of the conducting airway zone?
Upper respiratory tract to terminal bronchioles
NO ALVEOLI here
First 16 generations of tracheal tree represent conducting zone
What is the function of the conducting zone?
Provide passage for air into and out of gas-exchange areas of the lung
gas exchange DOES NOT occur in conducting zone
What is DEAD SPACE?
Inspired air that does not reach gas exchange
Where is the dead space “located”?
conducting zone
Describe air flow in conducting zone
Initially–fast through trachea due to small cross section
-slows as air travels down divisions of tracheal tree (larger cross sectional area)
What are the three defensive mechanisms of the conducting zone?
- Mucociliary escalator: mucous secreting cells create mucous blanket which traps foreign particles & cilia always moving mucous toward pharynx, blow or swallow nose for removal
- cough via irritant receptors in the trachea & conducting airways to protect deeper structures of conducting zone
- sneeze via irritant receptors in the nose–protect front end of conducting zone
What happens with particles bigger than 10 micrometers in diameter?
- filtered and trapped by nasal hairs
- irritant receptors lining the nasal passages initiate the sneeze reflex for removal of particles
What happens with particles 2-10 micrometers in diameter?
- mucociliary transport system lining the airways proximal to terminal bronchioles
- irritant receptors in airway lining initiate cough for removal of particles
What happens to particles <2 micrometers in diameter?
My reach alveoli (RESPIRATORY ZONE)
- -migrating phagocytic macrophages engulf foreign particles on alveolar surface and degrade them
- -non-degradable particles with sharp profiles such as: silica dust and asbestos fibers injure alveolar epithelium and alveolar macrophages leading to inflammation and scar formation –> PULMONARY FIBROSIS
What are the sections of the respiratory airway (zone)? What is this zone formed by?
Formed by respiratory bronchioles to alveolar sacs
Transitional section of respiratory zone–alveoli found from 17th-19th divisions
Respiratory section–alveoli completely line 20-22nd divisions
Alveolar sacs represent the 23rd generation
What occurs in the respiratory bronchioles?
first site of gas exchange
What are the PORES OF KOHN?
They allow adjacent alveoli to exchange air between each other
What does the alveolar septa consist of?
Epithelial layer and basement membrane (thin elastic layer that allows gas exchange)
What types of cells are in the epithelial layer of the alveolar septa?
Type I alveolar cells (provide physical structure of alveoli) and Type II alveolar cells (produce surfactant, a lipoprotein that coats the surface of the alveoli)
What is the role of alveolar phagocytes?
- Ingest and remove foreign particles/bacteria
- Removal through lymphatics located in terminal bronchioles–phagocytes migrate up to terminal bronchiole
- -NO COUGH REFLEX THIS DEEP
What is the composition of the wall in the trachea?
Anterior/lateral: C shaped cartilage
Posterior: smooth muscle
Mucosa–ciliated pseudostratified columnar epithelium with goblet cells, basement membrane, lamina propria, elastic fibers
Submucosa–rich in blood vessels and glands (serous, mucous, mixed)
Cartilage in C-shape (smooth muscle completes the ring)
Adventitia–(C.T.; associated with blood vessels, nerves, and sometimes fat)
What is the composition of the wall of the larger bronchi–smaller bronchi?
Cartilage continues but progressively diminishes into distal airways
Mucosa: ciliated pseudostratified columnar epithelium with goblet cells, tinner lamina propria in smaller bronchi, elastic fibers
Smooth muscle in spiral arrangement
Submucosa w/ glands
Cartilage plates
Adventitia
What is the composition of the walls of the bronchioles?
No cartilage, no glands
Ciliated columnar cuboidal; goblet cells only in larger bronchioles, some CT
Smooth muscle bundles
Elastic fibers and collagen
What part of the respiratory tract is NOT lined by mucous producing cells and ciliated cells?
- respiratory bronchioles
- anterior 1/3 of nose
- portions of pharynx
What is the job of ciliated cells?
Beat 600-900 beats per minute to provide waves to provide physical movement for mucociliary escalator
What are the mucous producing/secreting cells in the epithelial lining?
- Single exocrine cells –secrete OUTSIDE body–located between ciliated cells
- Found along airways: GOBLET CELLS (proximal to bronchioles) & CLARA CELLS (in terminal bronchus)
What are the mucous glands in the epithelial lining?
- -secrete mucous
- -found deep in submucosa (3rd layer-connective tissue)
- -located throughout respiratory tract
What is chronic bronchitis?
hypertrophy of mucous producing cells produces too much mucous and obstructs airway
What is intubation?
continues to produce mucous but removal mechanisms are impaired
What is cystic fibrosis?
Genetic disease of many organs of body (sweat glands, GI/pancreas, lungs) causing excessive mucous, sweat and digestive juice production
pulmonary dysfunction occurs: mucous accumulation in lungs promotes infection
What is pulmonary circulation?
un-oxygenated blood flow from right ventricle travels to pulmonary capillaries for gas exchange
What is bronchial circulation?
oxygenated blood flow from left ventricle supplies structures of pulmonary system
What are the functions of pulmonary circulation?
- facilitates gas exchange
- acts as a reservoir for left ventricle
- acts as a filter system to remove particles/emboli (clots or air)
What happens at alveolocapillary membrane?
Gas exchange (ratio of blood to surface area) 100 ml of blood in the capillaries is spread across 70-100m2 of aveolocapillary membrane (1/10 of liter spread out over an area of 10m/10m)
What kinds of damage can be done to alveolocapillary membrane?
Plasma/blood can leak into alveolar space
Impair gas exchange
What is hypoxic vasoconstriction?
LUNGS only: if damage or partial pressure O2 drops, the arterioles direct blood away from site
OPPOSITE of systemic circulation
What makes bronchial circulation unique?
It does not participate in gas exchange because it’s part of systemic circulation
Bronchial arteries supply structures of lungs (conducting system, pleura, etc)
What is the function of bronchial circulation?
Supplies nutrients to structures of lungs
- Some of bronchial veins create functional RIGHT TO LEFT shunt of blood flow
- R->L shunt: un-oxygenated blood passing into oxygenated circulation
- Bronchial capillaries (deoxygenated) drain into pulmonary veins (oxygenated)
What is lymphatic drainage?
Drains structures of lungs–located throughout tracheal tree through the terminal bronchial
-NO lymphatic vessels located in respiratory bronchioles, alveoli ducts, alveoli; no lymphatic vessels in sites of gas exchange
How do lymphatic vessels drain and protect the alveoli?
Accumulating fluid in the alveoli and the alveolar macrophages migrate up to the terminal bronchioles and then drain into lymphatic system at the level of terminal bronchioles
What makes up the chest wall?
Ribs and intercostal musculature
What makes up the pleura? (double folded serous membrane)
Visceral pleura: lines lungs
Parietal pleura: lines chest wall
What is the pleural space/cavity?
potential space created between visceral and parietal layers
What is in the pleural space?
Pleural fluid: secreted by pleura itself, normally thin layer within the pleural space, provides lubricant
Pressure in pleural space: low (negative or sub-atmospheric) -4 to -10 mmHg, allows lungs to expand and suck in outside air
What is the job of the pneumothorax?
Air enters into pleural cavity–increases pressure in pleural cavity so compresses or collapses the lung
