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
What is the primary function of the Pulmonary Circulation?
Deliver blood to the lungs for GAS EXCHANGE
What constitutes the largest vascular bed in the body? What are the metabolic functions of this vascular bed?
Pulmonary Arteries & Veins
- Convert Angiotensin I to ANgiotensin II
- inactivate Bradykinin
- Remove Seratonin, NE, Prostaglandins, Leukotriens, Drug metabolism
What is the mechanism of deposition of inhaled particles of the following sized particles
(state the Mechanism name & Site of Fx)
- Less than 0.1 um
- More than 5 um
- 1-5 um
- DIFFUSTION
- Alveoli - Impaction - Nasopharynx
- Sedimentation - Small airways
What are the 3 components of the mucociliary clearance system? What is the function of each?
- Mucus Layer - lies on top of periciliary fluid & traps inhaled particles
- Periciliary Fluid
- Cilia - in the periciliary fluid & only tips contact mucus layer
- propel mucus towards the pharynx where it is swallowed
Why is there no mucociliary clearance in alveoli? How are particles removed?
- no CIlia!
2. Macrophages engulf particles
What occurs if particles enter the bronchi?
- Particles Swallowed
- Mucociliary system transports particles via the bronchi
- Alveolar Macrophages engulf particles
What are the functions of upper airways?
Filter, warm & humidify air
What is the volume of the anatomic dead space? Respiratory Region?1
- 150 mL
2. 2.5 - 3 L (Surface Area 50-100 m2)
What do the respiratory duct & Alveolar Ducts compose?
1. Respiratory Segment
or
2. Basic Physiologic Unit
- Basic Physiologic Unit
The whole output of the right heart goes where?
The lung
What is the purpose of short capillary segments?
Blood forms a continuous sheet!
Does the lung have metabolic functions?
YES!
What removes inhaled particles in the lung?
Mucociliary Transport System
What is Tidal Volume?
Change in volume that occurs with cyclic breathing
What is IRV & ERV?
Volumes that can be in/exhaled in addition to the tidal volume during forced inspiration/expiration
What is residual volume?
Volume that remains in the lung even after forced ventilation
- cannot be measured with spirometry
What is VC?
Maximal amount of air that can be moved from deep expiration to deep inspiration
VC = IRV + Vt + ERV
What is FRC?
Volume of air in the lungs when all respiratory muscles are relaxed
- balance position of the lung chest wall system
FRC = ERV + RV
What is Inspiratory Capacity?
Volume that can be inhaled after all respiratory muscles are relaxed
IC = IRV + Vt
