respiratory physio 1 Flashcards
how does the composition of the bronchus, bronchioles and the alveoli differ?
- bronchi have smooth muscle for contraction but they also have cartilage that minimize how much the lumen can decrease in diameter
- bronchioles have smooth muscle and NO cartilage so there is a lot of contraction and decrease in diameter as there is no cartilage
- alveolus- no SM and no cartilage make it’s function purely flow thru the alveoli
what are sub mucosal tracheobronchial glands and what do they do? why? what type of nerves control their activity
- submucosal and tracheobronchial glands are mucus and serous producing cells underneath the basal surface of the epithelial cells of the respiratory system- PRESENT WHERE THERE IS CARTILAGE
- do so to make air easier/smooth to pass thru epithelial cells and to add humidity and warmth to the air as it enters
- controlled by the PNS mostly but also by SNS, peptidergic local inflammatory mediators
what are goblet cells?
mucus producing cells that are present every 5-6 ciliated cells and increase production of mucus when pollutants present
ciliated epithelial cells
what do they do?
what condition leads to a problem in this system?
- produce pericilliary fluid
- bring about Cl- secretion and Na+ absorption- along with Na comes water and a flushing of mucus
- does exchange in a RHYTHMIC CILIARY BEATING MANNER TO REMOVE AND WASH OUT THE MUCUS
- condition: cystic fibrosis= decrease in ability to secret Cl- and thus an inability to absorb Na and water = THICK MUCUS AND DIFFICULTY BREATHING
what are the three types of alveolar cells? what are their functions?
- Type I- main type of alveolar cells
- Type II- produce surfactant- a lipid that prevents alveolar and air wall collapse
- Alveolar Macrophages- patrol, phago inspired particles
what makes up a respiratory unit? what is it?
terminal bronchiole
alveolar ducts
atria and alveoli
-site of gas exchange
what are pores of kohn
what is the function of the structure?
What is the downside to this feature?
- bridges (pores) between alveoli
- means to collateral ventilation
- IF THE LUNG IS PARTIALLY DEFLATED, THEY SERVE AS PARTIAL VENTILATION
- ALSO ALLOW FOR PASSAGE OF OTHER MATERIALS LIKE FLUID AND BACTERIA
- downside- if there is an infection in one alveolus, then the others will be infected too
what surrounds the alveoli?
capillaries
where is the place where gas exchange occurs?
respiratory membrane between the capillary wall and the pulmonary epithelium
what are the layers of the respiratory membrane? what are some problems that disrupt each layer?
1) alveolar epithelium- pneumonia
2) epithelial basement membrane- emphysema
3) interstitial space- CHF that causes increase in BP that pushes fluid back to the interstitium and causes SOB and edema
4) capillary basement membrane- chemical intoxication damages them- causes fluid back into the interstitium and also into alveolar sac
what is credited for providing distensibility and elastic recoil to lungs? if you have more elastin in your interstitial space, would it be easier to breathe or harder?
fibroblasts that make collagen and elastin and are the primary cells of the interstitium
more difficult to breath with more elastin
what is the pleura and what is it’s fxn
-layer outside the lungs that make up the parietal and visceral layers of the pleura
-serous membrane folds back onto itself to form two layered structure
-has small amount of pleural fluid
-FXN: to transmit negative pressure produced by negative pressure made by chest expansion to lung parenchyma and alveoli during normal respiration
= PLEURAL FLUID IMPORTANT FOR THIS FXN
In terms of structure, what does the parietal pleura have that the visceral layer does not?
- parietal layer has stoma that drains the pleural fluid (and crap coming thru via systemic capillaries) out into the lymphatics
- visceral layer does not have stoma
what layer of the pleural layers of the lungs provides the most plural fluid? where does this fluid come from? what is the secondary source?
- parietal layer is where most pleural fluid comes from and it specifically comes from the intercostal arteries of the systemic circulation.
- this helps with smooth expansion of the lungs and transmission of pressure during respiration
- secondary- pulmonary capillaries on the visceral side
what are some reasons for a plural effusion?
1) CHF pt- pulmonary capillaries that drain out into plural space come from the pulmonary veins that drain directly into the LA. If you have CHF, you are not pumping well out of the LV so you have tons of back up that ends up backing all the way up to the pulmonary capillaries that drain a lot of the fluid into the pleural space causing a plural effusion
2) blockade of the lymphatic system
3) decreased microvascular oncotic pressure in the systemic capillaries that cause more fluid to flow out of the capillaries and enter the pleural space- can be due to kidney or liver dysfunction with proteins
4) decreased plural pressure (atelectasis) - due to collapse of a lung (pneumonia or tumor) that can cause a decreased pressure in the pleural space that would facilitate fluid from the systemic side to enter the pleural space
