To review for exam Flashcards
IP at apex of lung
-10cm H20
IP at base of lung
-2.5cm H20
Pleural pressure before inspiration
-3-(-5) cm H20
Lung compliance unit and def
mL/cmH20 : change in volume due to a 1cm H20 change in distending pressure
Unit of diffusion
mL/min
What is diffusion capacity DL?
measurement of the rate of transfer of gas from the alveolus to Hgb within a capillary
6 layers of respiratory membrane
- Surfactant
- H20
- Alveolar epithelium (type 1 and 2)
- Interstitial space
- Basement membrane of endothelium
- Endothelium
Graham’s law for gas diffusion
diffusion is inversely proportional to the square root of the molecular weight and directly proportional to the solubility coefficient
Total blood volume of pulmonary circulation
500mL (10% of circulating blood volume)
How much of the CO is the bronchial circulation?
About 1%
Which veins drain the lungs to the heart?
Either true bronchial veins or bronchopulmonary veins
What type of system is the pulmonary circulation?
Low pressure / low resistance system
What is the ventilation / perfusion ratio?
ratio of ventilation to blood flow (Va/Q)
Examples of perfusion limited gases
O2, N20
Examples of diffusion limited gases
CO, or an abnormal O2
VA/Q at the apex and base of the lungs
- Apex : 3.0
- Base : 0.6
Average VA/Q in the lungs
0.8
Which law states that the amount of gas dissolved in a liquid is proportional to the partial pressure above that liquid?
Henry’s law
What is the primary transport mechanism of O2?
oxyhemoglobin
What’s different about fetal hemoglobin?
higher affinity to O2 bc gamma SU doesn’t bind 2,3 BPG
How long do RBC usually spend in capillaries?
0.75 seconds
What does the O2 dissociation curve illustrate?
sigmoidal relationship bw pO2 in blood and number of O2 molecules bound to Hgb
What is the usual P50 of O2 dissociation?
27mmHg
What is the haldane effect on O2/CO2/Hgb?
oxygenation of blood displaces CO2 from Hgb : reduces affinity of Hgb to CO2
What are the 4 types of hypoxia?
- Hypoxic hypoxia
- Anemic hypoxia
- Circulatory hypoxia
- Histotoxic hypoxia
How long does it take for our body to use up all the stored O2 in heavy exercise?
1 minute
How much is the alactacid oxygen debt?
3.5 liters
How much is the lactic acid oxygen debt?
8 liters
Max O2 consumption during exercise
5100 mL/min
Pulmonary ventilation during max exercise
110L/min
Max breathing capacity
160L/min
CO during max exercise
30L/min
What is the safe range of tissue pO2?
20-60mmHg
H20 vapor pressure in the alveoli
47mmHg
3 centres in brainstem that control breathing and their location
- Medullary center (reticular formation)
- Apneustic center
- Pneumotaxic center (upper pons)
Other name for the inspiratory center
pre-bottzinger complex
Where can we find breathing mechanoreceptors? (4)
- Lung tissue
- Joints
- Muscles
- Alveolar wall (J receptors)
Where is the inspiratory center located?
DRG
Typical anion gap
8-16 mEq/L
Henderson Hasselbach equation
pH = pK + log10 (base / acid)
- Base : actual HCO3-
- Acid : alpha * PCO2
Which acids do the kidneys get rid of?
Non-volatile acids in the urine
Normal range for PaCO2
38-42mmHg
Buffer base definition
amount of strong acid that needs to be added to 1L of oxygenated blood in order to restore it to normal condition
Example of non volatile acid
H2CO3
Determinants of Net Acid secretion
NAE = titrable acidity + NH4+ excretion - HCO3- excretion
Which cells sense arterial pH in PCR?
type 1 glomus cells
Which drugs could cause respiratory acidosis?
opioids
What buffers H+ intracellularly?
intracellular proteins, organic phosphates
Which drugs could cause respiratory alkalosis?
aspirin
Marker substances for dilution method
- D20 Deuterium oxide (heavy water) for total fluid
- Inulin for ECF
- Evans blue (protein dye) for plasma
3 subdivisions of ECF
- Intravascular fluid (plasma)
- Interstitial fluid
- Transcellular fluid
Special property of membrane lipids
Amphipathic : hydrophilic heads and hydrophobic tails
Membrane proteins classification (basic)
integral / peripheral
3 classifications for ion channels
- By gating mechanism
- By type of ion
- By cellular localization
Another name for ligand gated ion channels
ionotropic receptors
Types of calcium channels
L, P, N, R, T
Localization of P and R type VDCC
cerebellar neurons
Localization of T-type VDCC (3)
neurons, osteocytes, cells with pacemaker activity
What type of receptor is Ryr?
Ion channel, activated by increase in cytoplasmic Ca2+ (releases Ca2+ INTO the cell)
Which equation can be used to calculate the equilibrium potential?
Nernst equation (neglects mb permeability for an ion)
Equilibrium potential of Cl- in the striated muscle
-88mV
Which equation can we use to calculate the membrane potential?
The Golden Hodgkin Quatz equation
Which enzyme inactivates cAMP?
phosphodiesterase (cAMP to 5’AMP)
2 examples of receptors that activate Gs
- Beta adrenergic receptors
- ACTH receptor
What does PLA2 form?
arachidonic acid
What does arachidonic acid activate? (3)
- Epoxygenase (HETE, ETE)
- COX (prostac, prostag, thromboxin)
- Lipoxigenase
What is the visual receptor and its protein?
Rhodopsin, coupled to transducin
3 proteins involved in regulation of cholesterol synthesis
- insig
- SCAP
- SREBP (2)
Which neurons get information for osmoregulation?
magnocellular neurons of the supraoptic and paraventricular nuclei of the hypothalamus
What is Ca2+ bound to in the ER?
Calsequestrin and calreticulin
What are the intermediate filaments in the smooth muscle?
vimentin + desmin
Which cells produce the slow waves in SM?
interstitial cells of Cajal
Which molecule inhibits the actin / tropomyosin in SM?
calponin
Which molecule inhibits the myosin in SM?
caldesmin
Which molecule does Ca2+ bind to in the cytosol?
Calmodulin
Which enzyme can inactivate SM contraction?
MLC phosphatase
4 processes stimulated by ATII
- Aldosterone synthesis
- Na/H exchange in PT
- ADH secretion
- Vasoconstriction in arterioles via Gq, increase TPR
What effect does aldosterone have on BP?
It affects bp by increasing ENaC expression on principal cells of the distal tubule / collecting duct
What is the main transporter that maintains osmotic gradient?
Na+/K+ ATPase
Where can we also find osmoreceptor cells?
mouth, stomach, intestine, liver
What can enhance ADH secretion?
decreased effective circulating volume
Which cells alter blood volume by detecting changes in NaCl?
Macula densa cells (JGA)
Where can we find the adenosine A1 receptor in autoregulation of GFR?
on the extra glomerular mesengial cells
NaCl filtered per day
1500g
What does parathormone inhibit in the kidney?
phosphate reabsorption in the proximal tubule via Gs
What inhibits carbonic anhydrase and thus Na+/HCO3- reabsorption in the kidney?
acetazolamide
What drug inhibits Na/K/2Cl co transporter?
furosemide (loop diuretic)
Which drug inhibits the Na/cl co transporter in the DCT
thiazide
Which 3 drugs can have an effect on ENaC in connecting, cortical + outer medullary collecting ducts?
Aldosterone : enhance via expression regulation
Amiloride : K sparing; inhibits
ANP : decrease via inhibition
2 cell types in the collecting duct
Principal cells (for reabsorption) Intercalated cells (alpha and beta) for H+ and HCO2-
Which protein anchors thick filaments to the Z disk?
titin for thick filament (also stabilizes)
Which proteins anchor the thin filament to the Z line?
CapZ protein and alpha actinin
What are the 3 prevertebral ganglion of sympathetic system?
- Celiac 2. superior mesenteric 3. Inferior mesenteric
