What happens when ventricular pressure falls below atrial pressure?
The atrioventricular valves open. - These valves separate the atria and ventricles
... [Show More] and open when ventricular pressure falls low enough.
Stroke volume is:
The amount of blood that flows from the ventricle during contraction. - Stroke volume x heart rate gives the value for cardiac output.
In the image above representing the cardiac cycle, label A represents
Atrial and ventricular diastole - Both the atria and ventricles are relaxed (no valves open).
Ventricular ejection is indicated by which label in the image of the cardiac cycle above?
D - During ventricular ejection, the aortic valve is open.
Referring to the image of the cardiac cycle above, in order to move from B to C, which of the following must be true?
Ventricular pressure becomes higher than atrial pressure - When this occurs the atrioventricular valves close.
Referring to the image of the cardiac cycle above, the point at which ventricular pressure falls below aortic pressure occurs between which two steps?
D and A - During this step, ventricular pressure falls below aortic pressure, causing the aortic valve to close.
Automaticity of the heart refers to its ability to:
Initiate its own contractions.
While the electrical signal is passing through the cells of the AV node:
The atria are contracting. - The electrical signals pass slowly through the AV node in order to provide enough time for the atria to fully contract.
Pressure in the venules is:
Lower than the pressure in the capillaries. - Blood flows from the capillaries into the venules, so pressure in the capillaries must be higher than that in the venules.
If you have your blood pressure measured at the doctor's office as 110 over 70, this means that:
Your pulse pressure is 40. - Pulse pressure is the difference between the systolic pressure and the diastolic pressure.
Choose the statement that best describes cardiac output.
The amount of blood, in L/min that leaves the left ventricle each minute.- Cardiac output is the amount of blood being delivered to the tissues each minute.
Refer to the graph above. How does the pressure at the distal end of the arterioles compare with that at the proximal end of the arterioles?
It is approximately 45 mmHg less. - Proximal pressure is approximately 80 mmHg and distal pressure is approximately 35 mmHg for a difference of 45 mmHg.
In the graph above, label 3 is:
Diastolic pressure. - Diastolic pressure is the low point of each pulse pressure.
Which structure(s) of the heart is/are most responsible for maintaining the one way flow of blood through the heart?
Heart valves. - Heart valves only open in one direction, keeping blood flow directed.
The heart helps maintain flow through the circulation by _________.
increasing the pressure of the blood as it moves out of the heart - Blood enters the ventricles at very low pressure (often near 0 mmHg). As the ventricles contract, they increase the pressure of the blood, propelling it through the circulation.
Preload would best be describe as:
End-diastolic volume - Preload is the amount of blood in the ventricle before it contracts, which is represented as end-diastolic volume.
A change in contractility represents:
A change in stroke volume. - A contractility change represents a change in stroke volume at a given preload.
If arterioles constrict, blood pressure ________________.
increases - Constriction of arterioles represents an increase in vascular resistance, which increases blood pressure.
If vascular resistance stays the same, how do decreases in cardiac output affect blood pressure?
Blood pressure decreases - As cardiac output decreases, blood pressure decreases.
Which of the following statements is true regarding the transport of oxygen and carbon dioxide on hemoglobin?
Nearly all oxygen is transported bound to hemoglobin, but only a small fraction of carbon dioxide is transported this way. - Most carbon dioxide is transported as bicarbonate.
Training at altitude can benefit aerobic athletes because:
They increase their hemoglobin levels. - Their red cell numbers increase, which also means their hemoglobin levels increase. [Show Less]