All Chapters Flashcards
Calcitriol MOA
acts on intestines, bone, kidney, and parathyroid gland
In intestines - enhances the absorption of Ca and Phosphate at the level of the enterocyte
In bone - promotes bone formation and mineralization by regulation of proteins produced by osteoblasts
Parathyroid gland - inhibits synthesis of PTH
calcitriol acts w/ PTH to increase Ca
Diastolic heart failure is due to….
primary impairments of ventricular relaxation, filling, or compliance or secondary to diseases of the pericardium
(ie HCM)
What happens in response to hypoxemia if there weren’t any carotid body receptors?
Hypoxemia would depress respiration
Equation to calculate corrected Na
= Na(measured) + 1.6 ( [measured glucose - normal glucose] / 100)
for every measured 100 mg/dl increase in BG, the measured serum sodium increase by 1.6 if < 400
If BG > 400 use correction factor of 2.4
List mediators that cause vasodilation
Prostacyclin
NO
In CHF, how do positive inotropes affect the frank-starling curve
Shifts it upwards (improves cardiac output)
What is the free water deficit?
= 0.6 * BW * ([ current Na patient / normal Na patient] -1)
Describe the renin-angiotensin-aldosterone system
Decreased blood flow and BP to the kidney results in activation of the renin-angiotension-aldosterone system
Renin is release from the juxtaglomerular cells in response to decreased baroreceptor activity, sympathetic activity, or decreased tubular chloride as sensed by the macula dense.
Generation of angiotensin II causes vasoconstriction (direct by triggering vascular smooth muscle contraction) and indirect (stimulation of sympathetic activity and release of vasopressin)
Antiogensin II promotes Na and water rendition in the proximal tubule and alters glomerular filtration through preferential constriction of the efferent arteriole.
Aldosterone release results in K excretion and Na retention in the cortical collection duct
How does sudden correction of arterial hpoxemia cause further hypercapnia?
(1) depression of formerly hypoxic-driven peripheral chemoreceptors
(2) relief of hypoxic pulmonary vasoconstriction in poorly ventilated lung regions that further reduces the ability of these units to eliminate CO2
(3) significant correction of hypoxemia causes better saturation of Hgb so that previously buffered protons on oxyhemoglobin are released w/ subsequent generation of new CO2 from stores (Haldane effect)
Vasopressin receptors?
V1 - vasoconstriction and increase in SVR
V2 - renal collecting duct promotes water retention to help support blood volume and preload
Mechanism of pulmonary edema secondary to HCM
b/c of elevated filling pressure caused by diastolic dysfunction
cats rarely develop systolic dysfunction and positive inotropes are actually contraindicated
Where in the brain are the generation centers for respiration?
Medullary respiratory center
Apneustic center
Pneumotaxic center
How does Cushing’s result in a hyper coagulable state
elevated fVIII and vWF
Elevated PAI-1
Elevated IX, XI, XII
Describe the baroreceptor system
Fall in stretch - identified by carotid sinus and aortic arch, stimulus to the vasomotor center of the medulla is decreased
Result is an increase in sympathetic
Decrease in parasympathetic outflow
leads (via catecholamines) to vasoconstriction (increase in SVR) and increased HR and contractility (and thereby CO)
…all functioning to raise BP back to normal
What is early after depolarization and delayed afterdepolarization and which electrolyte changes induce these?
Triggered activity results from small membrane depolarizations that appear after an are dependent on the upstroke of the action potential.
Early afterdepolarizations - occur during the process of depolarization
- hypokalemia and drug-induced prolongation of the QT segment increases the risk of EADs
Delayed after depolarizations - occur after full depolarization
- occur secondary to intracellular calcium overload associated with sustained tachycardia and digoxin toxicity
Describe the MOA of ADH
Stimulus for ADH release = low circulating volume and elevated plasma osmolality
(baroreceptors sense low stretch w/ decreased ECV and send impulses to the pituitary gland that simulate ADH release)
in the absence of ADH - renal tubular cells cannot reabsorb water –> ADH is responsible for activating the V2 receptor on the renal collecting tubular cell (aquaporin-2 molecules are inserted into the cell’s luminal membrane)
Define the ATT scoring system
Six categories
- Perfusion
- Cardiac
- Eye/muscle/integument
- Nervous
- Skeletal
- Respiratory
Scoring 0-3 w/ 3=severe injury
What type of immune reaction is a reaction to a RBC transfusion and why won’t Benadryl be of help?
Type II - antibody mediated
diphenhydramine results in decreased histamine and histamine plays a role in a type II hypersensitivity reaction
How do ammonia and glutamine cause seizures in HE?
Glutamine and ammonia result in overstimulation of the NMDA receptor by glutamate and ammonia
..in part b/c of free radical formation
What serves as a counterregulatory process to RAAS and SNS
natriuretic peptide system (ANP, BNP)
Circulating ANP and BNP is increased in dogs/cats with heart disease, roughly in proportion to disease severity
Define PaCo2 by using minute ventilation and VCO2
PaCO2 ~ VCO2 / VA
what is the definition of diffusion impairment?
Thickened respiratory membrane
ie ARDS, oxygen toxicity
Calculate the dosing for albumin replacement
Albumin deficit (grams) = 10 * (desired albumin - patient albumin) * weight * 0.3
HSA is a 25% solution (25 grams in 100 mls = 2.5 g/ml)
There are 3 characteristic shapes of ventilator waveforms - name them and include what they mean
Square - indicated that a given parameter changes abruptly but is then held constant for a period of time
Ramp - indicate that a parameter is changing gradually over time
Sine - patient efforts such as seen w/ spontaneous breaths in CPAP or SIMV
Effect of diuretics on the frank-stalling heart curve
Reduce preload, shift to the left
What is the main site for Mg resorption
Loop of henle
What are the three characteristic shapes of ventilator waveforms?
Square
Ramp
Sine
Fxn of endothelin
Postent vasoconstrictor produced by vascular endothelial cells in response to sheer stress, angiotensin II, and other various cytokines
Directly alters normal calcium cycling within muscle cells and is directly toxic to myocardiocytes
