SOLUTIONS GRADED A+ TIP
✔✔Trachea Histology - ✔✔Z0
fair amount of CT (smooth muscle & cartilage)
Cartilage rings turn to cartilaginous plates
pseudostratified ciliated columnar epithelium
trachealis smooth muscle
hyaline cartilage
✔✔Segmental Bronchi histology - ✔✔Z4-Z7
Plates of cartilage turn to smooth muscle
smooth muscle can constrict very forcibly
✔✔Terminal Bronchioles histology - ✔✔Z16
No cartilage, little smooth muscle
membranes getting thinner
✔✔Respiratory Bronchioles histology - ✔✔Z17
Alveoli begin
No cartilage or smooth muscle
single layer of Type I and II alveolar epithelial cells
transition zone (end of conducting, beginning of alveolar)
✔✔Type II Epithelial Cells - ✔✔make surfactant
✔✔Alveoli - ✔✔Surrounded by elastic fibers which give lung stretch during inspiration
allows recoil during expiration
Alveolar macrophages keep alveolar surfaces sterile
Pores between alveoli allow connection to adjacent alveoli and equalization of air
pressure
✔✔Path of Oxygen Diffusion - ✔✔1. Alveolar fluid
2. Alveolar epithelium
3. Epithelial basement membrane
4. Interstitial space
5. Capillary basement membrane
6. Capillary endothelial cell membrane
7. Blood
8. Red cell membrane
,✔✔How long do RBC stay in capillary network - ✔✔0.75 seconds and traverse about 3
alveoli
✔✔how many times faster does CO2 diffuse than O2 - ✔✔CO2 fives times faster
because of increased solubility (bc of carbon)
even though CO2 & O2 ~same size
✔✔Inspiration and Expiration - ✔✔Tidal Volume breathing is about .5 liters of air per
breath (~12x/min)
Do work breathing in, breathing out is passive
✔✔Inspiration Muscles - ✔✔Diaphragm is main (main force generator)
- contracts (moves down) during inspiration
Secondary are external intercostals (elevate ribs) and sternocleidomastoids (elevate
sternum)
*use secondary during exercise
Posterior/ middle anterior scalenus (elevate upper ribs)
parasternal intercartilaginous muscles (elevate ribs)
✔✔Expiration Muscles - ✔✔Passive using recoil of lung to push air out
Secondary expiration muscles are internal intercostals and the abdominal muscle
(depress ribs/ pushes up on diaphragm)
These force air out as opposed to passive
Rectus abdominus, external oblique, internal oblique, transverse abdominis
✔✔Diaphragm - ✔✔Force generator for ventilation
muscular dystrophy: requires artificial respiration - accessory muscles are insufficient for
ventilation
inspiration: contracts (moves down)
expiration: relaxes (moves up)
✔✔spirometry - ✔✔measuring lung volumes
determines sufficient lung volume
✔✔Tidal Volume (Vt) - ✔✔Normal breathing volume
air inhaled/ exhaled normally from rest
0.5 L
✔✔Expiratory Reserve Volume (ERV) - ✔✔Volume expelled past normal tidal volume
2L
, ✔✔Residual Volume (RV) - ✔✔Amount of air remaining in the lungs after a forced max
exhalation
1.2 L
can't blow out (stays in lung airways)
✔✔Forced Vital Capacity (FVC) - ✔✔Also just Vital Capacity (VC)
Forced exhalation after deepest inspiration
- range from max inspiration to max expiration
5 L (measurement of time within)
Decreases with pulmonary disease
✔✔vital capacity (VC) - ✔✔volume of air exhaled after max inspiration
what we can use functionally
ERV + TV + IRV
5 L (only L)
✔✔Total Lung Capacity (TLC) - ✔✔Maximum volume expansion
RV + VC
6L
✔✔Functional Residual Capacity (FRC) - ✔✔Amount of air remaining after Tidal
Volume Breath
person at end of Vt
RV + ERV
2.5 L
✔✔Inspiratory Reserve Volume (IRV) - ✔✔Volume of air that can be inhaled after a
normal inspiration
normal breath in then max inspiration
2.5 L
✔✔Inspiratory Capacity (IC) - ✔✔Amount of air that can be inhaled after normal
expiration
TV + IRV
3L
✔✔RV Measurements - ✔✔RV (or components with RV - TLC/ FRC) cannot be done
via spirometry - cannot expend more air or lungs would collapse
Measured via helium dilution
Spirometry measure vital capacity (ceiling to floor) & all components
✔✔Transpulmonary Pressure - ✔✔Alveolar Pressure - Pleural pressure
Amount of pressure pushing lungs out
Atmosphere is 0 cm H2O