2/25&2/26 Flashcards
Velocity of air vs turbulence.
-whats the relation?
Higher the velocity = more turbulence possible.
Where is the least airway resistance in bronchial tree?
Terminal bronchioles
- large number in parallel, resistance reduced, airflow reduced, least turbulence.
- dont forget about adding resistance in parallel. It reduces the resistance.
How far do the cartilage & goblet cells extend?
- To end of bronchi
- bronchioles dont have it.
Pseudostratified ciliated columnar cells extends to:
-Beginning of terminal bronchioles, then transition to cuboidal cells.
Airway smooth muscle extends to:
-end of terminal bronchioles.
epithelium of repiratory bronchioles
-cuboidal
- epithelium of alveolar ducts?
- what type of cell are type 1 pneumocytes?
- simple squamous
- type 1 pneumocytes = squamous
-what type of cell is type 2 pneumocyte?
-cuboidal
Where are clara (club) cells found?
- are they ciliated?
- function?
- terminal bronchioles
- non-ciliated low-columnar/cuboidal.
- secrete component of surfactant, degrade toxins.
- has cytochrome P450 enzymes
Whats the most important lecithin in surfactant?
-dipalmitoylphosphatidylcholine (DPPC).
-at what age are mature levels of surfactant reached?
- 35 weeks
- production starts at 25 weeks.
Lecithin-to-sphingomyelin ratio
-what ratio signals mature fetal lungs?
> 2:1
Which lung has lingula?
- left
- homologous to right lung’s middle lobe.
Aspirate a peanut:
- While upright
- While supine
- lower portion of right inferior lobe.
- superior portion of right inferior lobe, posterior segment of right upper lobe.
Relation of the pulmonary artery to the bronchus at
each lung hilus is described by:
RALS
-Right Anterior; Left Superior.
What travels w/aorta thru diaphragm?
-thoracic duct & azygos vein.
Vital capacity vs total lung capacity
-total lung capacity includes residual volume.
What is the greatest contributor to functional dead space?
- apex of healthy lung.
physiologic dead space
- what does it include
- whats the equation?
- includes both anatomic and functional dead space.
- Taco, Paco, Peco, Paco
-VD = VT × (Paco2–Peco2)/Paco2
Does relaxed or taut Hb have high affinity for O2?
- relaxed
- Relaxed in respiratory tract
- Taut in tissues
Inc. or dec. Cl- favors Taut form of Hb (right shift on curve).
inc. Cl
- just like inc. H (dec pH), inc temp, inc 2,3 BPG, etc.
Methemoglobinemia
-presents w/what?
-cyanosis & chocolate colored blood.
Treating cyanide poisoning: steps:
1-Oxidize Hb to metHb using nitrites (not nitrates).
2-metHb bill bind to cyanide
3-Use thiosulfate to bind this cyanide forming thyocynate which is renally excreted.
What drugs can lead to metHb formation?
aka which drugs can oxidize Hb
-nitrites, TMP, procaine, metoclopramide.
What does O2 graph look like when CO bound to Hb?
-dec efficacy and loses its sigmoidal curve.
O2 content equation
- (O2 binding capacity * % sat) + PAO2
* O2 binding capacity = (Hb)(1.34)
O2 sat = ?
O2 satured Hb.
-fraction of oxygen saturated Hb relative to total Hb.
Anemic: whats her O2 stats like?
- Hb will be dec, but O2 sat will be fine b/c theres less Hb total but still they’re all gonna be saturated w/O2.
- PAO2 will be normal.
-O2 content, however, will be decreased.
O2 delivery to tissues =
=CO * O2 content
Is a healthy persons lungs perfusion or diffusion limited?
perfusion limited.
In the diffusion equation
- what does emphysema do?
- what pulmonary fibrosis do?
- dec. surface area of diffusion = dec diffusion
- inc. thickness = dec diffusion
Is big A or little a for alveoli?
Big A = Alveolar
What can chronic sleep apnea potentially cause?
pulmonary HTN and right heart failure.
Ethambutol
- mech
- toxicity
- blocks arabinosyltransferase: carb polymerization of mycobacterium cell wall.
- optic neuropathy, red-green colorblindness
Ethambutol mnemonic
Ethambutol sounds like ethanol. Arabs drink a lot of ethanol. When you’re hammered you cant see straight.
- Arabs = arabinosyltransferase
- Cant see straight = optic neuropathy
Influenza vaccine: how does it prevent infection?
- inhibition of viral entry into cells.
- neutralizing Abs against hemagluttinin.
Bronchopneumonia:
Lobar pneumonia:
Interstitial pneumonia:
- patchy inflam. of a number of lobules.
- inflam. infiltrate confined to walls of alveoli.
- involves an entire lobe.
4 stages of lobar pneumonia
1- first 24 hrs - congestion: Bacterial alveolar exudate.
2- days 2-3 - red hepatization: Alveolar exudate = RBCs, fibrin, neutros.
3- days 4-6 - gray hepatization: RBCs disintegrate. Alveolar exudate = neutros & fibrin.
4- Resolution: enzymatic degradation of exudate.
Nystatin
-mech
- binds ergosterol & pokes holes in membrane
* same as amphotericin B, except this is topical form.
- Why do COPD pts wheeze?
- what will breath sounds sound like?
- air being forced through narrow, congested airway.
- diminished breath sounds b/c overall dec in airflow.
- What are the two types of asthma?
- Which one is a skin test useful for Dxing?
1-atopic asthma
*skin test can help Dx atopic asthma.
2-non-immune mediated asthma (bronchial hypersensitivity)
*both involve mast cell degranulation (pretty sure thats true).
What molecule is released specifically by mast cells & can be used as marker for mast cell activation/degranulation?
tryptase
Where do umbilical arteries originate from?
fetal internal iliac arteries
Umbilical arteries & vein are derived from..
allantois
Cyanide toxicity
-mixed venous blood oxygen content, inc or dec.
- inc.
- less aerobic metabolism = less O2 used.
Asebestos exposure
-pleural plaques more freq on which pleural layer?
- parietal pleura.
* just b/c you have pleural plaques doesn’t mean u have mesothelioma.
beta-naphthylamine
-predisposes to what cancer?
- found in alanin dyes & rubber industry.
- bladder carcinoma.
What is the normal PAO2 (alveolar)?
104 mmHG
What is normal PaO2 of incoming venous blood?
40 mmHG
*will normally be equilibrated w/alveolar PO2 after only the first 1/3 of pulm caps. That shit equilibrates fast.
What is the normal PaO2 (arterial)?
-104 mmHG before entering the LA
- 100 mmHG after entering the LA
- diluted w/deoxy bronchial blood.
What is the PaO2 cutoff for hypoxemia?
80 mmHG
Normal A-a gradient?
-not higher than 10-15 mmHG
Does physiological shunting lead to inc/normal/dec A-a gradient?
-inc. A-a gradient
but I believe that CO2 levels remain normal
Omalizumab
Mab: anti-IgE.
-binds mostly unbound, free serum IgE.
Alveolar gas equation =
PAO2 = PIO2 - PaCO2/.8
V/Q ratio
- at apex
- at base
- apex: V/Q = 3
- base: V/Q = .3
Both ventilation and perfusion increase from apex to base (base has highest of both). Perfusion inc. to a greater degree though. Thus; as one moves down the lung, the V/Q ratio will decrease b/c Q increasing more so than V!
What happens to V/Q ratio during exercise?
-With exercise (inc. cardiac output), there is vasodilation of apical capillaries, resulting in a V/Q ratio that approaches 1.
What is a shunt?
V/Q = 0
- no ventilation, so even 100% oxygen wont help b/c its not reaching the alveoli for some reason.
- ie. someone choking
Haldane effect
In lungs, oxygenation of Hb promotes dissociation of H+ from Hb. This shifts equilibrium toward CO2 formation; therefore, CO2 is released from RBCs.
-protons attached to Hb help stabilize the taut form *which is why low pH (lots of H) causes right shift.
Bohr Effect
In peripheral tissue, H+ from tissue metabolism shifts curve to right, unloading O2.
Reponse to high alt
- dec PaO2, dec PaCO2 (hypervent)
- inc. EPO, inc 2,3-DPG
- inc. mitochondria
- inc. renal excretion of bicarb (comp for resp alk)
- chronic hypoxia => pulm vasoconstrict => RVH
*can augment loss of bicarb w/acetazolamide.
Blood gas changes during exercise
- No change in Pao2 and Paco2
- inc. venous CO2 content
- dec. venous O2 content.
*your tissues extracting more O2 and producing more CO2.
rhinosinusitis
-most common causes?
- Most common acute cause is viral URI
- may cause superimposed bacterial infection
- S. pneumoniae
- H. influenzae
- M. catarrhalis.
DVT:
- Virchow triad:
- Homan sign:
- triad = stasis, hypercoag, endothelial damage.
- sign = dorsiflexion of foot = pain.
thrombophilia means what
inc. susceptibility to forming thrombi.
Fat emboli
- common causes:
- classic triad:
- long bone fxs, liposuction
- hypoxemia, neurologic abnormalities, and petechial rash.
- Pre-capillary AV-shunts will open up due to inc. pulm pressure. This is how fat emboli get thru and land in the CNS.
- fat molecules get coated by platelets which leads to thrombocytopenia and then petechiae.