Karteikarten
A & P Test Four - 7.12
Karten in diesem Stapel (35)
- 1How can venous system increase cardiac output when needed?When veins are constricted, large quantities of blood are transferred to the heart, thereby increasing cardiac output.
- 2Venous tone equalsvenous distensibility
- 3What is distensibility?The ability of a blood vessel to stretch. This allows the veins to accommodate pulsatile flow from the heart. Provides flow even through the smallest vessels.
- 4What is vascular compliance?The total quantity of blood that can be stored in a given portion of the circulation for each mmHg of pressure. It is the ability of vessel to stretch and hold volume.
- 5How do you calculate compliance?Distensibility X Volume = Compliance
The compliance of veins is 24 times that of arteries. - 6How do distensibility and compliance differ?Distensibility describes the characteristics of the veins. The compliance is a measurement of the quantity of blood that can be stored in the circulation. Compliance considers volume as well as distensibility.
- 7How do you calculate pulse pressure?Systolic pressure - Diastolic pressure
- 8What's another name for an incisura? What is an incisura?The dicrotic notch. Produced when the aortic valve closes.
- 9How does stroke volume affect pulse pressure?When stroke volume increases, this increases pulse pressure. If stroke volume decreases, this decreases pulse pressure.
- 10How does pulse pressure affect arterial compliance?Decrease in compliance results in an increase in pulse pressure. An increase in compliance decreases pulse pressure.
- 11What is the mean arterial blood pressure?The driving force for the blood flow in the arteries.
- 12What is mean arterial pressure more influenced by? Diastolic or systolic pressure?Diastolic pressure
- 13What are the most distensible vessels? How much more distensible are they?Veins. They are eight time more distensible.
- 14What is vascular tone?Vascular smooth muscle is normally in a semi-contracted state.
- 15Describe the nature of driving pressure in a rigid tube.A rigid tube has a linear relationship between driving pressure and flow.
- 16Describe the nature of driving pressure in a distensible tube.The relationship is non=linear. As pressure inside the tube increases, the size (radius) of the tube also increases, thus meaning the walls are distended.
- 17What is the relationship of resistance and flow in a distensible tube?Resistance decreases with an increase in flow. Small, distensible vessels exposed to high pressures will exhibit less resistance to flow than at normal pressures.
- 18What is the Law of LaPlace?Tension is a measurement of pressure. Wall tension is proportional to radius. Tension is the internal force generated by a structure. The formula is T = P X R. T is wall tension, P is pressure of the fluid within the cylinder and R is the radius of the tube.
- 19What are the consequences of LaPlace's Law with respect to the diameter of cylinders.To withstand the same internal pressure, a large-diameter cylinder must have thicker walls than a small-diameter cylinder
- 20What types of vessels are most likely to rupture?Larger-radius vessels are more likely to rupture because they have higher wall tension. Examples include an abdominal aortic aneurysm.
- 21How does the Law of LaPlace apply to the filing pressure of the left ventricle?The tension in the ventricular wall increases as filling increases
- 22Is MAP lower downstream or upstream?It is lower downstream. Systolic pressure is higher in larger arteries than in aorta.
- 23Damping and loss of pulse pressure is directly proportional to what?Resistance and compliance. The greater the resistance, the more difficult it is to transmit pulse pressure. The greater the compliance, the greater the damping of the pulse pressure.
- 24Describe how arteriosclerosis affects pulse pressure.Arteriosclerosis
Vessels become less compliant
Pulse pressure increases to nearly twice normal - 25How does aortic stenosis affect pulse pressure?Aortic Stenosis
Aortic valve opening decreased
There is diminished blood flow thru the valve
So the pulse pressure is significantly decreased - 26How does a patent ductus arterioles affect pulse pressure contours?Patent ductus arteriosus
Major portion of blood pumped into aorta from left ventricle flows backward thru the open ductus arteriosus into pulmonary artery and lung circulation
Diastolic pressure falls very low before the next heartbeat - 27How does aortic regurgitation affect pulse pressure?Aortic Regurgitation
Aortic valve incompetent —does not close completely or may be absent
Blood pumped from left ventricle flows immediately back into left ventricle
Aortic pressure can fall all way to zero between heartbeats
No dicrotic notch either - 28Name the value of widened pulse pressure.Greater than 40 mmHg
- 29What are the causes of widened pulse pressure?Isolated systolic hypertension –
Aortic regurgitation
– Thyrotoxicosis
– PDA
– Aortic coarctation –
anemia - 30What is the value for narrowed pulse pressure?Less than 30 mmHg
- 31What are some causes of narrowed pulse pressure?– Tachycardia
– Severe aortic stenosis –
Constrictive pericarditis –
Pericardial effusion
– ascites - 32How do you calculate MAP? What are the normal values for MAP?MAP – [(2 x diastolic) + systolic] / 3
• Diastole counts twice as much as systole because 2/3 of the cardiac cycle is spent in diastole
• MAP of ~ 60 mmHg required to perfuse coronary arteries, brain, kidneys
• Usual range is 70 to 110 mmHg - 33What is another name for central venous pressure?Right atrium pressure
- 34What factors increase Right Atrial Pressure?• Factors that increase RAP: -
increased blood volume -
increased venous tone
- dilation of arterioles -
decreased cardiac function - 35How are the veins inside the skull affected in regards to central venous pressure?• veins on inside of skull are negative pressure b/c they are in noncollapsible chamber
• Problem occurs during craniotomy and opening of sagittal sinus
• Can suck in air leading to a venous air embolus (VAE)
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- Karteikarten am A & P Test Four - 7.12, erstellt von Rachel Nall am 03/07/2016.
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- Rachel Nall
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