exam 1 Flashcards
t/f Inflammatory pathways promote thrombosis, which is responsible for myocardial infarction and most strokes
true
What is released from the endothelial wall, that promotes vasodilatation and limits platelet extension?
prostacyclin (PGI2)
Released from the platelet that promotes vasoconstriction and potentiates platelet degranulation?
Thromboxane A2
Which of the following is effective at dissolving blood clots
Plasmin – dissolves clots (from plasminogen)- only clot buster we talked about
name an anticoagulant we spoke about
Heparin; others include chelators, and dicumarol
What is the key step in blood coagulation?
the conversion of fibrinogen to fibrin -(necessity for this conversion - Thrombin)
What is the key step merging of the intrinsic/extrinsic pathways
the activation of factors X and V
the release of platelet granule contents…
are potentiated by Thromboxane A2, not essential for the process to occur
Fibrinogen and prothrombin along with factors VII, IX, X are produced by which organ?
liver (nothing on other organs related to clotting factors
Concerning Ca++ role in blood clotting, which of the following statements is true?
required at all steps except the 1st two intrinsic steps
At a normal resting membrane potential of -85 mV, which of the following ions is closest to its Nernst equilibrium potential?
K+
during resting potential Fast Na, Slow Ca/Na are closed, K+ are open, therefore K+ ions free to move when they reach their Nernst equilibrium potential
A 2-3 X elevation in extracellular fluid of what ion can cause flaccidity and weakness of cardiac muscle in part by decreasing the resting membrane potential?
K+
What is the effect of elevated Ca++ ?
Spastic contraction
If end diastolic volume = 160 ml and end systolic volume = 120 ml; what is the ejection
fraction?
25%
160-120= 40 40/160 = .25
What percentage of blood from the atrial to the ventricle is actively pumped?
25-30%
Norepinephrine binds to which cardiac receptors?
Beta
muscarinic receptors are blocked by…
atropine (S72)
At rest, if you block both divisions of the autonomic nervous system, which of the following changes would occur?
HR will increase and strength of contraction will decrease
At rest, if you block the sympathetic nervous system, which of the following changes would occur?
both HR and strength of contraction will decrease
At rest, if you block the parasympathetic nervous system, which of the following changes would occur?
both HR and strength of contraction will increase
if you stimulate both divisions of the autonomic nervous system, which of the following changes would occur?
HR will decrease and strength of contraction will increase
what dominates inhibitory influence on HR, SNS – stimulatory influence on contraction
parasympathetic nervous system
What allows the action potential to spread from one cardiac cell to an adjacent cardiac cell, and therefore allows the heart to behave as a syncytium (many acting as one)?
intercalated discs
What delays the wave of depolarization from entering the ventricle, and allows atria to contract slightly ahead of the ventricles
AV node
what creates only a diastolic murmur?
mitral stenosis -Diastolic
what creates only a systolic murmur?
aortic stenosis
pulmonic stenosis
what creates a diastolic and systolic murmur? (combined valvular defect)
patent ductus arteriosis
what causes a diastolic insufficiency
aortic and pulmonary insufficiency
what causes systolic insufficiency
mitral and tricuspid insufficiency
systolic problems
A+P Stenosis, M+ Tri Insufficiency, its reversed for diastolic.
Reperfusion injury following infarction is primarily associated with which of the following?
free radical production
overdrive suppression
drive a self-excitatory cell at a rate faster than its own inherent rate, you will suppress the cell’s own automaticity
sympathetic activity
+ HR, +Strength of contraction, +Conduction velocity
If the left atrial pressure is 7 mmHg., the left ventricular pressure is 100 mmHg., and the aortic blood pressure is 106 mmHg., what is the status of the valves on that side of the heart
mitral and aortic valves closed
rememeber the heart is all pressure gradients
Increased stretch on the ventricular fibers during filling, have what effect on calcium influx into the ventricular cells?
increase
“More Ca++ influx into cell associated with increased stretch, and increased venous return”
Which of the following has a positive inotropic effect on the ventricle.
thyroxine – Thyroid hormones have a +Inotropic (inc strength) & +Chronotropic (Inc HR) & Inc CO by Inc BMR
A wave of repolarization moving toward the positive recording electrode would create what type of deflection?
negative deflection
Depole Towards (+) & Repole Toward ( - )
positive
Depole Towards (-) & Repole Toward ( + )
negative
When does myocardial blood flow peak in the left ventricle?
at the onset of diastole
Which of the following statements regarding a prolonged QT interval (increased incidence of sudden cardiac death) is true?
males are more susceptible than females
Prolonged QT also associated with Left Stellate Ganglion stimulation, higher propensity to develop ventricular fibrillation
If the sympathetic nerves to the heart are cut, and then the SNS is stimulated, heart rate will
still increase, why?
circulating norepinephrine/epinephrine from the adrenal medulla
Under resting conditions, what percentage of oxygen is extracted by the myocardium from the perfusing coronary blood flow?
70%
The preferred energy substrate of ventricular cardiac cells is which of the following?
fatty acids - 70%
others include: glucose, glycerol, lactate, pyruvate, amino acids
At a constant operating pressure what happens to the wall tension as the radius of that chamber decreases?
decreases
No consistent relationship of P waves to QRS complexes describes which of the following?
3rd o AV block
1st degree
Depolarization wave from atria to ventricle is delayed excessively (But it still happens)
2nd degree
Some depolarization waves pass, others blocked
3rd degree
All depolarization waves from atria to ventricles are blocked
As heart rate increases, cycle length decreases, which of the following statements is true?
diastole shortens more than systole
at resting HR: systole
Most of the energy consumed by the heart for work is utilized for which of the following
pressurization of blood by the ventricles >99%
An inverted T wave is associated with which of the following?
ischemia
An elevated ST segment is associated with which of the following?
infarction
A PR interval greater than .20 sec. is associated with which of the following?
first degree AV block
A prolonged QRS complex (>.12 sec) is associated with which of the following?
left ventricular hypertrophy
A PR interval less than .1 sec. is associated with which of the following?
inadequate delay, possible accessory conduction pathway from atria to ventricle
What is the major function of the AV node?
delays the wave of depolarization from the atria to the ventricle
What is the major function of the SA node?
normal pacemaker of the heart
What is the major function of intercalated discs?
allows the ventricle to depolarize as a unit
Which of the following changes in ion flux will slow the heart rate?
increased K+ efflux
Which of the following changes in ion flux will increase stretch of the heart
increase in Ca++ influx
A traumatized vessel will constrict; most of the constriction is due to which of the following?
local myogenic spasm
induced constriction from pain
SNS reflex contraction
