exam 2 14 Flashcards
primary function of lungs?
gas exchange
supportive function of gas exchange
mucocillary clearance
air conditioning
regulation of airflow
heat exchange
what kind of lungs for a squamate?
•Squamates (lizards, snakes) don’t have diaphragms, instead use axial musculature that they also use for movements, so they often can’t breath while running!
turtle lung structure
- Some have a layer of muscle surrounding their entire lungs
- Others have diaphragm-like structure
O2 and CO2 move by ___, from an area of high to low partial pressure
simple diffusion
A = alveolar duct
B = capillaries
C = individual alveoli
pneumocyte= alveolar type 1 cells
blue= cytoplasm of an endothelial cell
arrows = blood gas barrier
Ficks law
Vgas= A/T (D)(P1-P2)
The amount of gas that moves across a sheet is:
- Proportional to the area of the sheet•Inversely proportional to its thickness
- P1 is the partial pressure on one side, P2 on the other
- A=area
- V= flow (V is volume, the • means over time, so vol over time is flow, right?)
- D = diffusion, a constant, how big and how soluble the molecule is
CO2 diffuses ___ than O2 – it’s MW is similar, but it is way more soluble
20x faster
Diffusion constant is higher than O2 (ficks law)
conducting airway
•Trachea → mainstem bronchi → lobar bronchi → segmental bronchi → → → terminal bronchioles (smallest without alveoli)
bronchus (can see cartilage and alveolar)
blue= pulmonary artery (deoxygenated)
red= pulmonary vein (oxygenated)
smaller bronchi/bronchioles (smooth = no cartilage= deeper airway) and alveoli
what blood vessel type runs along conducting airway
arteries-
veins will branch off earlier and do their own thing
holes in alveolar
pores of kohn- function unknown
air bypass hurt alveoli
tissue repair- crawl
alveolar ducts
•Progression of ____ in larger airways to simple cuboidal and squamous in the alveoli
pseudostratified columnar
respiratory epithelium is found ___
conducting airway
alveolar epithelium is found
respiratory zone
alveoli- where gas exchange takes place
conducting airways has what type of epithelium
respiratory epithelium
4 types of cells in conducting airway
- Basal Cells
- Ciliated Cells
- Goblet Cells
- Club cells
basal cells are found in __ and act as __
conducting airway
stem cell
___ act as the stem cells in conducting airway
basal cell
goblet cells
mucous producing
•Mucins fill and expands the apical portion of the cell, forcing the nuclei to the basal position and giving it a goblet shape
ciliated cells
- “multiciliated” or “motile ciliated” ∼300 motile cilia into the periciliary layer
- Critical for propelling the mucus layer up the airway
- “Mucocilliary clearance”
- Terminally differentiated
____ beat in unidirection to move stuff out of lungs. this is called ___
ciliated cells
mucocillary clearance
what does it mean when ciliated cells are terminally differentiated?
can not turn into anything else
can’t reproduce or change
mucociliary clearance
sweeps particles out of lungs
club cells
- Cuboidal, non-ciliated
- Produce “secretoglobins” AKA “uteroglobins”, thought to have innate immune functions
- Also produce some surfactant proteins
- Expression of cytochrome p450 enzymes allows for detoxification of xenobiotics
- In mice, these can serve as a stem cell in smaller airways that lack basal cells. Unclear in other species
cub cells produce ___ thought to have innate immune functions
“secretoglobins” AKA “uteroglobins”, thought to have innate immune functions
club cells produce __ to help with detoxification of xenobiotics
cytochrome p450
what works as stem cells in mice in smaller airways
club cells
no basal cells in smaller airways, club cells will take over the job
ionocytes
Unknown function, but express high levels of CFTR(cystic fibrosis), thought to regulate mucous viscosity and thus mucociliary clearance
tuft cells
Unknown function, hypothesized to modulate Th2 immune responses (i.e. allergy, parasites)
neuroendocrine cells
Modulate Th2 immune responses (i.e. allergy, parasites)
How are these different from tuft cells? Good question.
Recently demonstrated to act as oxygen sensors
what type of cells in respiratory zone?
alveolar type 1 and alveolar type 2 cells
alveolar macrophages
where gas exchange happens
alveolar type 1 cells- very thin- very big
___ cells are large, squamous•Cover 95% of lung surface area•Ultrathin•Facilitate gas exchange between air and blood
alveolar type 1 cells
alveolar type II cells
- Cuboidal, non-ciliated, possess lamellar bodies
- Produce surfactant proteins and phospholipids
- Facultative Stem / Progenitor Cell!
main function of alveolar type II cells
produce surfactant
what type of cell acts as stem cells in alveolar epithelium?
alveolar type 2- usually makes surfactant but in times of need can act as a stem cell
function of pulmonary surfactant
•Decreases surface tension preventing the alveolar sac from collapsing
pulmonary surfactant are made in __ and secreted by __
lamellar bodies
type 2 alveolar cells
surfactant is hydrophilic. True or false
false
hydrophobic- type C most hydrophobic protein in the body- helps increase rate and spread of surfactant phospholipids over the surface of the lung
why have alveolar macrophage
no ciliated cells to get particles out
macrophages will eat anything bad left over
Pulmonary artery
•Thin wall•Less smooth muscle (still more than a vein though!)•Low pressure, 1/8 of systemic BP
Systemic artery (e.g. leg)
•Very thick wall•Lots of smooth muscle
capillary bed formation in frog lungs
intussusceptive angiogenesis (make pillars to increase surface area
bronchial circulation
•A smaller vessel, the bronchial artery, arises from the aorta (1% of cardiac output) and supplies oxygenated blood to the conducting airways to feed their metabolic functions
provides oxygenated blood to conducting airway
