Cardiovascular System Flashcards
Norepinephrine is a _______ that acts on ___ receptors.
- Neurotransmitter
2. B1 (beta 1 receptors)
What do phase 0 and 3 of the action potential graph stand for?
Phase 0 = action potential
Phase 3 = repolarization
Phases of the cardiac action potential.
Phase 0: Phase 1: Phase 2: Phase 3: Phase 4:
Phase 0: upstroke, action potential, Na+ conductance
Phase 1: initial brief repolarization
Phase 2: Plateau, transient Ca2+ conductance leads to inward Ca2+ current, both inward and outward current are the same
Phase 3: repolarization, Ca2+ conductance decreases and K+ conductance increases, K+ outward (Ik1) conductance increases leading to repolarization
Phase 4: resting membrane potential. Inward and outward currents of K+ are equal.
Plateaus occur when charge fluxes balance each other out.
Sinoatrial Cardiac Cycle
Phase 0: Phase 1: Phase 2: Phase 3: Phase 4:
Phase 0: upstroke, action potential, Ca2+ conductance
Phase 1: does not exist here
Phase 2: Does not exist here
Phase 3: repolarization, Increase K+ conductance increases, K+ outward conductance increases leading to repolarization
Phase 4: slow depolarization
This is related to the right atrial pressure and is called the END DIASTOLIC VOLUME (EDV):
Perload
Note: An increase in venous return leads to an increase in EDV
An increase in preload refers to:
An increase in end diastolic volume (EDV) and an increase in venous return
The slope on the venous return curve of the cardiac vascular function curve is determined by
The resistance of arterioles.
BRS physiology, pg. 79, 5th Ed
Stroke volume =
EDV - ESV
EDV= end diastolic volume
ESV = end systolic volume
Cardiac output =
Stroke volume x heart rate
Ejection fraction =
Stroke volume / EDV
(EDV - ESV)/ EDV
Related to ventricular contractility and a normal value is 55%
Stroke work =
Pressure x Volume
Aortic Pressure x Stroke Volume
Cardiac Output =
Oxygen consumption / (O2 pulmonary vein - O2 pulmonary artery)
What is the S4 heart sound represent?
Filling of the ventricles by atrial systole.
What describes
1) activation of atria
2) precedes or come before the P wave
3) causes the S4 heart sound
4) a wave of venous pulse
atrial systole
what describes:
1) begins at onset of the QRS wave, which represents activation of ventricles
2) S1 heart sound occurs
3) AV valve closes, ventricular pressure > atrial pressure and corresponds to the first heart sound
4) Splitting in first heart sound may be because the mitral valve closes before the tricuspid
Isovolumetric Ventricular Contraction
What describes:
1) ventricular pressure reaches its maximum
2) aortic valve opens, ventricular pressure > aortic pressure
3) stroke volume is ejected during this phase
4) onset of the T wave occurs (ventricle contract and rapid ejection)
Rapid Ventricular Ejection
What describes :
1) decreasing ventricular ejection and decreasing atrial pressure
2) atrial filling continues
Reduced Ventricular Ejection
What describes:
1) end of the T wave
2) during this phase, closure of the aortic valve and then pulmonary valve occurs
3) S2 heart sound occurs
4) Mitral valve opens, when the atrial pressure > ventricular pressure
Isovolumetric Ventricular Relaxation
What describes:
1) Mitral valve opens and ventricular filling from atrium begins
2) S3 heart sound occurs (Normal in children, abnormal in adults)
Rapid Ventricular Filling
What describes:
1) Longest phase of the cardiac cycle
2) Ventricular filling continues but at a slower rate
Reduced Ventricular Filling (diastasis)
Heart sound S1 occur in
Isovolumetric contraction and systole. It is the loudest heart sound.
Heart sound S2 occur in
Isovolumetric relaxation; aortic and pulmonary valve closure; during diastole.
Heart sound S3 occur in
Only heard in children and pregnant women; abnormal in healthy adults.
Diseased adults have CHF, mitral regurgitation and associated with increased filling pressures.
Heart sound S4 occur in
Known as the “Atrial kick”
Occurs in late diastole. S4 heart sound is associated with ventricular hypertrophy.
Nitric Oxide
NO is an endothelial derived relaxing factor (EDRF). EDRFs cause relaxation of vascular smooth muscles.
What organ/ circulatory system is describe to:
1) use 5% cardiac output
2) local metabolite control
3) vasoactive metabolite = adenosine
4) metabolite causes compression during systole
Coronary Circulation
What organ/ circulatory system is describe to:
1) use 15% cardiac output
2) local metabolite control
3) vasoactive metabolite = CO2 and H+
4) increase in intracranial pressure causes a decrease in cerebral blood flow
Cerebral Circulation
What organ/ circulatory system is describe to:
1) use 20% cardiac output
2) local metabolite control
3) vasoactive metabolite = lactate, K+, and adenosine
4) sympathetic control is very important here (a1 receptors cause vasoconstriction; b2 receptors cause vasodilation)
5) muscular activity cause temporary decrease in blood flow
Muscle Circulation
What organ/ circulatory system is describe to:
1) use 5% cardiac output
2) local metabolite control is its least important mechanism of control
3) vasoactive metabolite = not important in this case
4) sympathetic control is its most important mechanism
Skin Circulation
What organ/ circulatory system is describe to:
1) use 100% cardiac output
2) most important local metabolite control is hypoxia
3) vasoactive metabolite = hypoxia
4) hypoxia causes vasoconstriction (eliminates) non-functioning components
Pulmonary Circulation
Name vasodilator metabolites:
1) CO2
2) H+
3) K+
4) Lactate
5) Adenosine
All are release because the tissue supply of O2 is matched to the tissue demand for O2, become out of balance. They lead to 1) increased arteriolar vasodilation, 2) increased blood flow 3) increased oxygen delivery
An increase in blood flow to an organ occurs after period of occlusion is called:
Reactive hyperemia
An increase in blood flow due to increase in skeletal muscle activity is called:
Active hyperemia
Histamine causes:
1) arteriolar dilation and
2) venous constriction
The combined effect of both arteriole dilation and venous constriction causes increased Pc of the Starling equation which leads to increased filtration resulting in edema. Tissue trauma causes release of histamine.
Bradykinin causes:
1) arteriolar dilation and
2) venous constriction
The combined effect of both arteriole dilation and venous constriction causes increased Pc of the Starling equation which leads to increased filtration resulting in edema. Similar to histamine.
Serotonin (5-hydroxytryptamine) causes:
1) arteriolar constriction
Serotonin is release when blood vessels are damaged and leads vasoconstriction to prevent blood loss.
Prostaglandins cause:
Name 4 types of prostaglandins:
1) Prostacyclin: vasodilator in several vascular bed
2) E-series prostaglandins: vasodilateeerrrs
3) F-series prostaglandins: vasoconstrictors
4) Thromboxane A2: vasoconstrictor
Most important local vasodilator for cerebral circulation:
CO2
Sympathetic innervation is primary regulator of blood flow to the skeletal muscle:
at rest.
Arterioles are densely innervated densely sympathetically fibers; veins are innervated less densely.
Sympathetic innervation of a1 (alpha 1) receptors cause:
Vasoconstriction
Sympathetic innervation of b2 (beta 2) receptors cause:
Vasodilation
Low cerebral pressure causes
Fainting
A. Initial responses to standing:
B. Compensatory mechanisms:
A. Arterial blood pressure - decrease; cardiac output - decrease; stroke volume - decrease; Central venous pressure - decrease;
heart rate - no change; TPR - no change
B. Compensatory Mechanism: ALL INCrease Arterial blood pressure heart rate cardiac output stroke volume TPR Central venous pressure
No P wave means the pacemaker is in the:
AV (atrioventricular) node.
What are the two isolectric regions of action potential?
PR and ST intervals
P wave (involves atria) ST wave (involves ventricles)
Fetal pulmonary blood flow volume.
Pulmonary fetal blood flow is nearly zero.
What receptor mediates constriction of arteriolar smooth muscle?
a1 receptors (alpha-1)
Diaphoresis means
Excessive sweating
