Flashcards in Cardiology Deck (25)
What are three functions of the pericardium?
"It is the layer on the outside of the heart
1. Provides support 'sports bra to the heart'
2. Allows the heart to not overfill.
3. Limits the filling of the heart in diastole"
What are the four components of a cardiac cycle?
1. Isovolumic contraction - no change in volume - all valves shut
3. Isovolumic relaxation - semilumar valves fill up, all vavles are shut again.
4. Diastole - filling of the heart
What are the three phases of diastole?
1. Rapid filling (blood has been waiting)
3. Atrial contraction (depolarization, pushes the last residual blood)
accumulates blood -> the contraction of the chambers of the heart (especially the ventricles) to drive blood into the aorta and pulmonary artery
What does the left aortic sinus gives rise to?
What does the right aortic sinus gives rise to?
The left coronary artery
The right coronary artery
rate of contraction/min, increased by sympathetic, decreased by parasympathetic
pertaining to cardiac contractile force.
the ability of the heart to fill; another word for myocardial relaxation
pertaining to the speed of impulse transmission.
List 5 factors to increase the myocardial oxygen demand/consumption
Conduction velocity (Dromotropy)
(the opposite decreases myocardial oxygen demand/consumption)
List at least 4 ways to enhance contractility (inotropy)
1. Increase affinity of Troponin C for calcium
2. Increase extracellular concentration of calcium ions (IV Ca)
3. β adrenergic receptor agonist (increases cAMP)
4. Stimulate the sympathetic nervous system (catecholamines)
5. Stimulate the RAAS (renin-angiotensin-aldosterone system)
6. phosphodiesterase inhibitors
7. Blockade of the Na/K ATPase pump
What structures undergo dilation in a PDA?
- Pulmonary artery (post PDA)
- Pulmonary capillaries
- Pulmonary vein
- Left atrium and ventricle
- beginning of aorta
List the steps that increase contractility after beta receptor activation of a myocardial cell
List 3 arterial receptors that mediate vasoconstriction
Alpha 1 adrenergic receptor
Angiotensin II receptor
What cardiac events are associated with S1?
What cardiac events are associated with S2?
What cardiac events are associated with S3?
What cardiac events are associated with S4?
Associated with closure of the A/V valves
Associated with closure of the semilunar valves
Associated with filling
(Normal in horse & cow)
Associated with atrial contraction
(Normal in horse & cow)
How do starling's forces promote edema?
Starling's forces effect the direction of fluid movement controlled by balance between blood pressure and osmotic pressure.
If blood pressure is too high or osmotic pressure is too low, edema will form.
What happens with premature beats?
- cause Tachyarrhythmias --> a heart rythym with premature beats causing the heart rate to speed up
--> increase in oxygen demand, decrease in filling time, decrease in time for coronary blood flow
They represent cells that are normally non-automatic that have acquired automaticity
(usually due to disease causing myocardial dilation)
How does tachycardia affect myocardial performance?
Part of myocardial performance is the amount of O2 required for contraction
- this is effected by wall stress, contractility and heart rate. If heart rate increases, more O2 is required.
Factors that promote venous dilation
ANS (M3 receptor/G-alpha-i)
Endothelium derived relaxation factor
Prostacyclin (activates G-alpha-s)
Bosantin (Endothelin receptor blocker)
Cause of heart murmurs
- Leaky valves
- Stenotic valves
- abnormal communications (shunts, A/V)
Cardiac ouput x Arterial resistance
Stroke volume x heart rate
Arterial resistance is proportional to...
Arterial tone (vasocontrition/vasodilation)
Compliance/stiffness of the arterial tree
Factors that promote venous constriction
- Renin/angiotensin system
- Arganine vasopressin
a peptide produced and secreted by endothelial cells that induces vasoconstriction
energy storage molecule used by most organisms (vasodilator)