Zhu: Intro to Respiration Flashcards
Most important function of the respiratory system?
Gas exchange
External respiration
what happens before mitochondria
Internal respiration
O2 reaches mitochondria –> O2 turns into water and CO2 is made
_______ ________ is the driving force of net air movement
pressure difference. (this gives net movement from high pressure to low pressure)
**2 Main components of dry air and their percent composition?
O2 (21%); N2 (79%)
Dalton’s Law
the pressure of a gas mixture is the sum of the partial pressures of the individual components of the gas mixture
Atmospheric Pressure?
760 mmHg
(Dalton’s Law): Partial Pressures of O2 and N2?
O2: 21% (760) = 160 mmHg
N2: 79% (760) = 600 mmHg
Partial Pressure is decided by __________
concentration.
Alveolus branches off at generation_____ at the end of the _____________
16; terminal bronchiole
What are the three components of the terminal respiratory unit?
respiratory bronchioles, alveolar ducts, alveolar sacs
Relationship of cross-sectional area, flow, and velocity?
F=V*A or V=F/A
Cross-sectional area _____through first 4 generations of airway, then _________.
falls; increases.
Bigger airways in beginning have a much _________ velocity. Air from smaller airways to alveoli is ________.
faster; slower. (v=f/a)
3 mechanisms of deposition?
impaction (for particles >5um), sedimentation (0.2-2), and diffusion (
Majority of bacteria is deposited via _______ in the ________. Airflow here is ________.
sedimentation; around the terminal bronchioles. slower.
Clearance of deposited articles: Two mechanisms?
Mucociliary Transport System, Alveolar Macrophages
3 Layers of Mucociliary Transport System?
Mucus Layer, Periciliary Fluid, and Cilia
Mucus Layer
secreted by goblet cells, clara cells, and submucosal glands. contains proteins (makes it sticky), glycoproteins, electrolytes, and water
Periciliary Fluid
secreted by pseudo stratified, columnar epithelium. contains electrolytes and water (no proteins therefore not sticky)
Cilia beat in which direction?
Towards pharynx –> how we can cough it up
Alveolar Macrophages
Contain lysozymes to kill bacteria. Destroyed by cigarette smoke. Smokers destroy macrophages with cigarette smoke so smokers end up with more respiratory tract infections.
Airway Resistance equation
Air flow = change in pressure/Resistance
Q=Change in P/R
Factors that influence Resistance in Airway
RADIUS RADIUS RADIUS. (Think of cross-sectional area!)
also viscosity and tube length.
Resistance and radius are inversely related thus as radius increases, resistance decreases.
Major site of airway resistance?
Large and medium bronchi (they have a smaller cross-sectional area!)
Ex: cig smoke increases the size and number of surface secret cells and submucosal gland and their output as well. parasympathetic stimulation can increase submucosal glad secretion. ==> decrease radius, increase resistance
Main site we can work on to increase or decrease radius?
Smooth Muscle:
Sympa dilation via B2-adrenergic receptors (**think: dilation is sympathetic - when you’re running, sympathetic takes over so your lungs need to be dilated)
Parasympathetic constriction via vagus nerve
Local secretion - induced constriction (mast cells release histamine; leukotrienes)
Pathophysiology of Asthma - example of airway resistance. What are the two key features?
Airway hyperresponsiveness (airway spasms/smooth muscle contracts) Airway inflammation (occurs over years)
4 Main factors of Airway resistance in asthma?
- edema (capillaries increase in permeability and proteins leak into tissue)
- increase in mucus (antigen - mast cells)
- SM hypertrophy d/t increased contraction over time
- cilia destroyed
