Exam II Questions Flashcards
You are placing leads on a patient in order to measure EKG. In order to get the highest level of EKG activity, how should the leads be placed?
Parallel to the control lead.
During pathological tachycardia, body temperature and sympathetic stimulation are increased. What feature of the heart DECREASES during pathological tachycardia?
Pumping ability.
During endogenous tachycardia, stoke volume does not fall even though filling time is reduced. Why does this occur?
There is sympathetic stimulation, which increases the strength of contractions.
Stokes-Adam syndrome is a disease that occurs from which type of heart abnormality?
complete AV block.
The velocity of blood flow through the capillaries is relatively low. What feature of capillaries causes such a low velocity?
Capillaries have a large cross-sectional area; (V = F/A).
In artherosclerosis, resistance is greatly increased due to a blockage in blood vessels. What property of blood vessels will be directly affected?
Capacitance; it is inversely proportional to resistance.
A vessel with high capacitance will have a low ____.
Elastance.
True or false: rate of blood flow is not controlled by local tissue needs.
False.
What is the total resistance in blood vessels?
1 PRU.
When conducting a cardiac experiment, you note that veins have a relatively high compliance. Based on this observation, do the veins have a low or high amount of elastic fibers?
low
You take a pulse pressure reading from a 15 year old patient. They have a high pulse pressure. What does this tell you about the compliance of their arteries?
They are highly compliant (PP = SV/AC)
You are studying arterial pressure in dogs and wish to calculate the mean arterial pressure. What equation would be useful for doing so?
Mean arterial pressure = diastolic + 1/3PP.
What is the most important determinant of resistance in a vessel?
Radius
After a large amount of angiotensin has been released into the blood stream, how will autoregulation affect blood pressure?
sympathetic innervation will cause an increase in pressure, but blood flow does not necessarily increase by as much.
What is the most important factor in vasomotion?
the concentration of oxygen in tissues.
What is the definition of compliance?
The ease with which a hollow viscus may be distended.
What is the definition of elastance?
The ease with which a hollow viscus may be recoiled.
After a long day, you decide to lie down. How wil lying down affect venous return?
It will increase (increased volume and pressure).
Aortic valve stenosis involves a decrease the diameter of a vessel. How does this affect pulse pressure?
Pulse pressure decreases.
Patent ductus arteriosus is what kind of shunt?
left-to-right shunt. It decreases pulse pressure.
How does autoregulation affect pulse pressure?
It decreases pulse pressure.
According to the vasodilator theory, an increase in metabolism results in what?
decreased oxygen in the tissues, which causes vasodilation.
According to the metabolic theory, an increase in oxygen to the tissues results in what?
inactivation of vasoregulatiors.
How does the brain attempt to autoregulate blood flow?
By dilating blood vessels, which washes out carbon dioxide.
You encounter a patient who has decreased nitric oxide levels. How will this affect vessel constriction/dilation?
The vessels will not be able to dilate as well because nitric oxide is responsible for dilating blood vessels.
Damaged blood vessels release what protein, and what does the protein do?
Endothelin; it causes vasoconstriction.
You encounter a patient in the ER that is suffering a heart attack. What are some factors that would increase vasodilation in the patient’s blood vessels?
Adenosine, bradykinins, histamine, potassium, prostacyclin/prostagalandins.
You are hiking and see a bear, which subsequently tries to attack you. What hormones will you most likely release, and how will they affect your vessels?
Epinephrine/norepinephine; they will cause vasoconstriction.
Does continual firing of nervous signals result in vasoconstriction or vasodilation?
vasoconstriction.
What is a term for the partial contraction of blood vessels?
vasomotor tone.
In a cardiac experiment, Herring’s nerve is abnormal in a cat that you are studying. What region of the brain will be affected?
Sensory area (medulla); constriction and vasodilation will be affected.