Questions and Answers
Which of the following would increase cardiac output? (Select all that apply)
Increasing end-diastolic and end-systolic volume will increase stroke volume.
False
What best describes afterload?
Afterload refers to the back pressure exerted by arterial blood.
Norepinephrine acts on the heart by ________.
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What is the formula for stroke volume?
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The pulse pressure is ________.
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What pressure is responsible for reabsorption and for pulling fluids into the venous end of capillaries?
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Which of the following would NOT move by diffusion across a capillary endothelium?
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Why is it important that blood pressure drop to lower levels as it reaches the capillary beds?
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A muscle that is being regularly contracted during exercise will attract blood flow by dilating arterioles. Which of these factors would contribute to the effect?
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Which of the following blood pressure readings would be indicative of hypertension?
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A patient with essential hypertension might have pressures of 200/120 mm Hg. This hypertensive state could result in all of the following changes except ________.
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The baroreceptors in the carotid sinus and aortic arch are sensitive to which of the following?
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As pressure in the aorta rises due to atherosclerosis, more ventricular pressure is required to open the aortic valve.
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Study Notes
Cardiac Output and Its Influencers
- Cardiac output can be increased by stimulating epinephrine release, which elevates heart rate and contractility.
- High blood pressure and decreased calcium during contraction do not contribute positively to increased cardiac output.
Stroke Volume and Volume Relationships
- End-diastolic volume (EDV) increases stroke volume (SV), while increased end-systolic volume (ESV) decreases it.
- The stroke volume can be calculated using the formula: SV = EDV - ESV.
Afterload Explained
- Afterload represents the back pressure from arterial blood that ventricles must overcome to eject blood.
- It indicates the tension needed to open the aortic valve.
Norepinephrine's Role
- Norepinephrine enhances heart function by accelerating the depolarization of pacemaker cells.
- It does not block calcium action or reduce stroke volume or contractility.
Pulse Pressure Definition
- Pulse pressure is defined as the difference between systolic and diastolic blood pressure.
Fluid Dynamics in Capillaries
- Osmotic pressure in capillaries (OPc) is critical for reabsorbing fluids into the bloodstream, particularly at the venous end.
- High dissolved material concentration in the blood attracts water, facilitating fluid movement.
Diffusion Limitations Across Capillaries
- Proteins cannot diffuse through capillary endothelium due to their size and typically exit via active transport mechanisms.
- Lipid-soluble substances, carbon dioxide, and oxygen can diffuse freely.
Capillary Pressure Significance
- Low pressure in capillaries prevents damage since they are delicate structures.
- Lower pressure still facilitates the movement of solute-containing fluids into interstitial spaces due to permeability.
Factors Affecting Muscle Blood Flow
- Increased carbon dioxide levels promote arteriolar dilation, enhancing blood flow to muscles during exercise.
Hypertension Indicators
- A blood pressure reading of 170/96 mm Hg signifies hypertension, in contrast to normal readings like 120/80 or 110/60.
Effects of Essential Hypertension
- Essential hypertension, with pressures of 200/120 mm Hg, leads to increased heart muscle size rather than a decrease.
Baroreceptor Sensitivity
- Baroreceptors located in the carotid sinus and aortic arch respond to changes in arterial pressure, influencing cardiovascular regulation.
Atherosclerosis and Aortic Pressure
- Rising aortic pressure due to atherosclerosis requires more ventricular pressure to open the aortic valve, highlighting increased workload on the heart.
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Description
Test your knowledge on cardiovascular physiology and the factors that influence cardiac output. This quiz includes questions on hormonal effects and neural stimulation related to heart function. Perfect for students preparing for the ANPS20 exam.
