cvs mcq Flashcards
Stretching a myocardial cell
E- allows more Ca2+ to enter and increases the force of a contraction
If blood pressure doubled at the same time that the peripheral resistance doubled, the blood flow through a vessel would be
E- unchanged
Manganese ions block the calcium channels in the cardiac muscle membrane. How would the presence of manganese in the extracellular fluid affect the contraction of the heart muscle?
C- the heart would beat less forcefully
Sympathetic stimulation increases the heart rate by
A- just increasing ion influx, this increasing the rate of depolarization
Joey develops a medical condition that decreases his blood viscosity. Assuming no other change (ex: no compensatory reflex), which happens to his blood pressure?
B- decreased
______ are also known as the pressure reservoir of the cardiovascular system
E- Arteries
Smooth muscle is present in the walls of
D- all vessel types except capillaries and venues
The values obtained when measuring blood pressure, such as 120/80
B- reflect the pressure in the major arteries during ventricular systole and diastole
Blood flow to a tissue will increase if the
B- level of carbon dioxide at the tissue increases
If cardiac output increases and resistance in arterioles does NOT change, what happens to the arterial blood pressure?
A- increases
In order to cause vasodilation of most vascular smooth muscle,
E- sympathetic stimulation is removed
Blood pressure and flow to the brain are monitored by receptors located in the wall of the
D- cerebral arteries
Which of the following is greater?
A- blood pressure when sympathetic stimulation to the heart increases
Capillaries are best described as
A- microscopic vessels in which blood exchanges material with the interstitial fluid
The purpose of having valves in the cardiovascular system is to
B- ensure that blood flows in one direction
The driving force for blood flow is a ______ gradient
C- pressure
Each of the following changes will result in increase blood flow to a tissue except one. Identify the exception.
B- decreased vessel diameter
The flattening of the action potentials of myocardial contractile cells, called the plateau phase, is due to a combination of ______ K+ permeability and _______ Ca2+ permeability
D- decreasing, increasing
The importance of the plateau phase of the action potential of myocardial cells is in
C- preventing tetanus
The AV node is important because it
B- delays the transmission of the electrical impluses to the ventricles in order for the atria to finish contracting
In order for the blood to enter the heart,
D- the atria must not only be at rest but the atrial pressure must be lower than the veins
Epinephrine and norepinephrine increase ion flow through ____ channels
E- If and Ca2+
Place these structures in the order that blood returning to the heart from the body would pass through them. 1. right ventricle 2. left atrium 3. right atrium 4. pulmonary artery 5. left atrium 6. pulmonary vein C- 3,1,4,6,2,5
Ivabrandine selectively blocks If channels in the heart. Which statement would be true concerning a patient who is taking this drug?
A- the drug would slow down this individuals heart rate
If the connection between the AV node and the bundle branches becomes blocked
B- the ventricles will beat more slowly
In which of the following situations would the end-systolic volume (ESV) be the greatest?
B- when parasympathetic stimulation of the heart is increased
If the EDV is 140 mL, which other values are most likely to occur in a healthy, normal person?
C- The ESV could be 50 mL and the SV could be 90mL
Acetylcholine slows the heart rate by
E- increasing the permeability to K+ and decreasing the permeability to Ca2+
Drugs known as calcium channel blockers can be used to
A- decrease the force of cardiac contraction
When blood pressure receptors sense a loss of blood pressure, they ________ their firing rate
A- increase
A certain drug decreases heart rate by producing hyperpolarization in the pacemaker cells of the heart. This drug probably binds to
B- muscarinic receptors
In the condition know as complete heart block, what happens?
B- electrical signals from the SA node never reach the ventricles, so the contraction of the atria is not coordinated with the contraction of the ventricles
ECGs
C- show the summer electrical potentials generated by all cells of the heart
During the isovolumic phase of the ventricular systole
B- the atrioventricular valves and semilunar valves are closed
If the membranes of the cardiac muscle cells in the SA node become more permeable to potassium ions
B- the heart rate will decrease
If there is a blockage between the AV node and the AV bundle, how will this affect the appearance of the electrocardiograph?
C- there will be more p waves than QRS complex
If a myocardial infarction results in the formation of scar tissue along the pathway of the left bundle branch
A- cardiac arrhythmia may occur
The rising phase of the action potential is a result of ______ for skeletal muscle, _______ for contractile myocardium and _______ for autorhythmic myocardium
B- Na+ entry, Na+ entry, calcium entry
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