Pulmonary 1 - Lecture 23 Flashcards
Where is O2 & CO2 exchanged? Transported?
- Exchanged in Alveoli
2. Transported in BLOOD via
What is termed internal respiration? What is External?
Mitochondria consume O2 and produce CO2
- Echange of air in Lungs via Alveoli
What are the 4 functions of the lung? What is the MAIN function of these 4?
- O2 IN & CO2 OUT!! = MAIN
- Barrier Function
- mucociliary clearance - Metabolism
- Angiotensin I, Seratonin - Host - Defense
- immune functions
What are the 4 components of the upper airway? 3 of the Lower airway? Where does gas exchange occur?
- Nose
- Pharynx
- Glottis
- Vocal Cords (Nose - Larynx)
- Trachea
- Bronchial Tree
- Alveoli
Gas exchange occurs in the LOWER AIRWAY
What are the main functions of the upper airway?
- Condition inspired air (temp/humidify)
- Nose filters particles > 10 micrometers
- Generate Resistance to airflow (50% in the nose)
Where is most airflow resistance found?
Nose
What is the purpose of the lobulation of the lung?
Greater movement of he torso w.o producing stress/strain forces on lung tissue
What area is the functional anatomic unit? The Basic Physiologic Unit?
- Bronchopulmonary segment
2. Respiratory unit (alveoli)
What is the anatomical dead space called? What airway generations fall in this category?
Which area participates in gas exchange? What is the transition zone? (where is it found)
- Conducting Airways
- zones 1-16 - Respiratory Unit
Transition zone is the area between the terminal bronchioles and respiratory bronchioles that are only partially alveolated - zones 17-19
As airway general increases, what else increases? This occurs in what zone?
Cross - Sectional Area
- Respiratory Zone
(also includes terminal bronchioles) - greater area = small forward velocity and thus gas moves chiefly by DIFFUSION (ventilation)
What type of cells coat the alveolar surface? What makes Type 1 cells so ideal for diffusion?
- Squamous Epithelial Cells
- very thin & LARGE AREA
What is the function of the sympathetic & parasympathetic systems in the lung?
Sympathetic: dilates airways
Parasympathetic : constricts the airway
What are the majority of alveolar cells? The 2%
- Type 1
- Type 2
Which of these cells produce surfactant?
Majority = Type 1
Type 2 produce surfactant
What makes up the Large Conduction Airway? What type of cells are in the epithelium? bronchioles? Capillaries?
- Epithelium - goblet cell (produce mucous)
- Basement Membrane
- Mucous Gland
- Cartilage - Bronchioles - no cartilage or mucous glands
- Capillaries - thin layer of alveolar epithelial cells & capillaries
What is sandwiched between the alveolar epithelium? How thick is the blood-air barrier? How does blood pass through the lungs?
- Pulmonary Capillary Endothelium
- thin & LARGE area- 0.4 micrometers - Blood passes as a SHEET flow
- capillaries are wider than they are long
What are the 3 main functions of SURFACE TENSION (without surfactant)?
- Resist being stretched
- Tends to reduce surface area
- Creates Tendency to recoil after stretch
What is the Law of Laplace for Alveolar Pressure?
Pressure = 2 x Surface Tension / Radius
P= (2T)/ r
Which cells are responsible for producing surfactant? Without surfactant, which alveoli (size) would collapse?
- Type 2 produce a lipoprotein complex
2. Reduce surface tension most in SMALL ALVEOLI –> more surfactant per unit area than larger alveoli
What would occur if there was no surfactant?
Large surface tension would collapse the alveoli/lungs due to the strong attractive forces of H20 molecules in the alveoli
Small alveoli collapse
Large alveoli become over distended
What is interdependence? What opposes the tendency to collapse?
Alveoli mechanically tethered together to prevent the tendency of collapsing the alveoli
- traction exerted by neighboring alveoli OPPOSE the tendency to collapse
What are 2 things that determine the STABILITY of alveoli?
- Surfactant
2. Interdependence
What collateral ventilation provides traction for the surrounding neighbor alveoli? (3)
- Pores of Khon
- Channels of Lambert
- Channels of Martin
What are the 2 vascular systems?
- bronchial Circulation (1-%CO)
2. Pulmonary
What Bronchial Vascular system is responsible for 1/3 of blood to the heart and 2/3 to the pulmonary circulation? What is this called?
- Bronchial Veins
3. Venous Admixture or Anatomic Shunt
