Cardiovascular Physiology Flashcards
Which of the following is not true of the SA Node:
1. Its cell membrane is naturally leaky to sodium ions
2. It has increase potassium leakage and decrease sodium conductance
3.It is capable of self excitation
4. It has the highest rhythmic excitation among the specialised excitatory and conducting system of the heart
5. its depolarization is secondary to calcium influx
- It has increase potassium leakage and decrease sodium conductance
DECREASE K+ Leakage and INCREASE Na+ conductance
What part of the cardiac cycle is when atrial pressure is greater than ventricular pressure
Rapid Filling
True or False
One of the factors in Blood flow to any organ is blood vessel length
True
Blood flow is impeded by friction between blood and the vessel wall. As the length of a vessel increases, the surface area in contact with blood also increases. This leads to greater frictional resistance, ultimately hindering blood flow.
True or False
ECG can show the strength of myocardial contraction
False
The ECG measures the electrical activity of the heart muscle as it depolarizes and repolarizes. While electrical activity precedes contraction, the ECG itself cannot directly assess the force or strength of the contraction.
True or False
The P wave is preceded by the systole
False
The P wave represents depolarization of the atria and is followed by atrial contraction (systole).
True or False
Presence of H+ brings about vasodilation
False
True or False
The heart’s ventricular muscle is directly stimulated by Purkinje fibers
False
While Purkinje fibers are essential for ventricular function, they act as conductors, not direct stimulators.
True or False
Increased cardiac contractility will cause a decrease in end systolic volume (ESV)
True
This stronger contraction allows the ventricles to squeeze more blood out during systole (contraction phase), leaving less blood behind in the ventricle at the end of systole.
True or False
Intraventricular pressure is increasing during Isovolumic contraction
False
The key characteristic of isovolumic contraction is the increase in pressure without a change in volume. This pressurization prepares the ventricles for forceful ejection of blood in the subsequent phase of systole.
It is the fastest specialized excitatory and conducting system of the heart
Purkinje Fibers
Central Venous Pressure is increased by:
Decreasing Heart Rate
True or False
Decreasing peripheral resistance can increase stroke volume
True
Decreasing peripheral resistance can be a contributing factor to an increase in stroke volume, particularly due to the enhanced venous return and the Frank-Starling mechanism.
In which area of the cardiovascular system where blood flow velocity is least?
Capillaries
In which area of the cardiovascular system where blood flow velocity is greatest?
Arteries closest to the heart, specifically the aorta and large arteries branching from it.
The first heart sound is best heard at the
5th ICS LMCL
The flow of impulses in the heart conduction system
SA Node–Internodal Tracts–AV Node–AV bundle–Bundle Branches–Purkinje Fibers
The heart murmur that is heard in systole is
Mitral Regurgitation
True or False
There is increased reabsorption of sodium and water in Acute Hypotension
False
The _________ has the slowest conduction velocity
AV Node
It mediates impulse conduction
between the atria and the ventricles
AV node
The SA node is the pacemaker of the heart because
It has the greatest intrinsic impulse
generation
Which of the following will increase cardiac output?
a. Increase afterload
b. Increase ESV
c. Increase venous return
d. Vasodilation
e. None of the above
C. Increase Venous Return
When more blood returns to the heart from the veins (increased venous return), the ventricles have more blood to fill during diastole (relaxation phase). This increased filling stretches the cardiac muscle fibers, leading to a stronger contraction in the subsequent systole (contraction phase) according to the Frank-Starling mechanism. This stronger contraction translates to a larger volume of blood being ejected with each beat, thus increasing stroke volume (SV) and consequently, cardiac output (CO).
Which part of the ECG preceeds isovolumic relxation
T wave
The T wave marks the end of ventricular repolarization, which signifies the end of electrical activity associated with ventricular contraction and the beginning of electrical recovery for the next cycle. Isovolumic relaxation follows ventricular repolarization and coincides with the descending limb of the T wave on the ECG.
It represents ventricular muscle depolarization
QRS complex
It is prolonged in the presence of bundle branch blockade
QRS complex
It is normally less than 40msec in duration
T wave
. Period where ventricular pressure is greatest
Ejection phase
Period where atrial pressure is greatest
Atrial systole
. Period where the semilunar valves are open
Ejection phase
In which part of the cardiac cycle will the aortic pressure be lower than the atrioventricular
Ejection Phase
An important ECG Finding in Acute MI is
ST Elevation
Which of the following ECG
waveforms is influenced by the
conduction velocity through the AV
node?
PR interval
The PR interval is influenced by the
conduction velocity through the AV
node.
Which of the blood vessels
provide the highest resistance in the
cardiovascular system
Arterioles
Contains the highest proportion of
blood in the CV system
Veins
It dilates Afferent Arterioles
Prostaglandin
It constricts efferent arterioles
angiotensin II
