Ch17 Flashcards
What are the muscles of inspiration?
Sternocleidomastoid, scalenes, external intercostals, diaphragm
What are the muscles in expiration?
Internal intercostals, abdominal muscles
Where do you begin to find smooth muscle in the lungs?
Secondary bronchus
How does water reach the lumen of the airway to thin the mucous of the goblet cells?
- NKCC transporter loads the epithelial ICF with Na+, K+, and 2Cl- from the ECF.
- Na+ and K+ are reintroduced to ECF by active and passive transport while the Cl- goes into the lumen
- Na+ goes through paracellular pathway to lumen, drawn by the Cl-
- Osmotic gradient of NaCl in lumen draws water
What does type 1 alveoli do?
Cell that allows for gas exchange
What does type 2 alveoli do?
Synthesizes surfactant
What is the “High flow, low pressure” portion of the circulatory system?
Pulmonary circuit
What is the normal blood pressure in the pulmonary circuit? How much blood is in it at a time?
25/8
About 0.5 L
About how much fluid is filtered in the systemic and pulmonary circuits a day? Why is there such a large difference?
Systemic loses 3L/day
Pulmonary loses 0.5L/day
Pulmonary circuit has lower hydrostatic pressure
How to calculate partial pressure with Dalton’s law
Partial Pressure= P(atm) x % of gas in atmosphere
Why does the atmospheric O2 diffuse into the lungs while the CO2 diffuses out?
The differences of the partial pressures create a gradient the molecules follow
What is Boyle’s Law?
P1V1=P2V2
What is flow rate proportional to?
Pressure gradient / Resistance
Why does the pleural space create a vacuum effect on the lungs?
The pressure in the pleural space is subatmospheric
Inadequate surfactant production leads to what kind of lung disease?
Restrictive
What is the law of LaPlace? What does it teach us about the lungs?
P=(2T)/r
T=surface tension
R=radius
The smaller alveoli have more surfactant. If this wasn’t the case the larger alveoli (that exhibit less pressure) would create a pressure gradient and the smaller alveoli would collapse into the larger alveoli.
What is lung surfactant composed of? What cells make it?
Proteins and phospholipids. Created by type II alveoli cells
What is the total pulmonary ventilation and how is it calculated? What is the normal measurement for adults?
Volume of air moved into/out of lungs each minute
Ventilation rate x tidal volume
12-20 breaths/min -> 6L/min
With a tidal volume of 500 mL and dead space of 150 mL, how much fresh air actually reaches the alveoli?
350 mL
Which is a more accurate indication of efficiency, total pulmonary ventilation or alveolar ventilation?
Alveolar ventilation
How is alveolar ventilation calculated? What is the normal measurement in an adult?
Ventilation rate x (tidal volume - dead space volume)
4.2 L/min
What is the normal maximum voluntary ventilation in adults?
125-170 L/min
How does the partial pressure of CO2 affect the tissue around the alveolus? How is this related to the effect of O2?
Increased CO2 in expired air -> bronchiole dilation
Decreased CO2 in expired air -> bronchiole constriction
Increased CO2 in interstitial fluid -> arteriole dilation
Decreased CO2 -> arteriole constriction
Exac
What is the difference between obstructive lung diseases and restrictive lung diseases?
Obstructive lung diseases increase airway resistance during expiration (constriction of airways is an example)
Restrictive lung diseases increase airway resistance during inspiration (example is inelastic scar tissue in the lung or insufficient surfactant production)
