Hemodynamics

Question 1

Define hydrostatic pressure in relation to the circulatory system

Answer 1

• pressure exerted by fluid blood against the walls of the blood vessels
• the force exerted by blood against the walls of blood vessels, driving blood flow throughout the CVS to deliver oxygen and nutrients to the tissues.

Question 2

What is Mean Arterial Pressure (MAP), and why is it important?

Answer 2

• MAP is the average arterial pressure during one cardiac cycle
• MAP is used for tissue perfusion and homeostatis

Question 3

How does a drop in Mean Arterial Pressure (MAP) at the level of the aorta affect the body’s ability to perfuse tissues?

Answer 3

• no tissue perfusion or homeostatis
• the aorta cannot maintain proper blood flow to the tissues throughout the body and cannot regulate homeostatis

Question 4

What factors can cause a drop in Mean Arterial Pressure (MAP)?

Answer 4

• gravity and body orientation
• resistance
• cardiac output

Question 5

What is Systolic Blood Pressure, how is it different from Diastolic Blood Pressure

Answer 5

• SBP: pressure in the arterties when the heart contracts
• DPB: pressure in the arterties when the heart rests between beats and refills with blood

Question 6

Why must the heart generate sufficient pressure, and how do the left and right ventricles contribute to this function?

Answer 6

• Effective Circulation
• Left Ventricle: pumps oxygenated blood to the aorta and to the, high blood pressure to overcome resistance
• The Right Ventricle: pumps deoxygenated blood into the pulmonary arteries and lungs, low blood pressure compared the left ventricle because it overcomes a lower resistance in the pulmonary circulation

Question 7

How does hydrostatic pressure vary throughout the circulatory system and with changes in the upright down body orientation?

Answer 7

• hydrostatic pressure increases in the lower parts of the body (legs and feet) due to the downward gravitional pull of blood
• aortic pressure increase to overcome the resistance created by the gravitational pull, especially when travelling upwards to the brain or circulating in the lower body
• the right atrial pressure remains lower to aid in the return of blood flow from the veins back to the heart.
• gravity aids venous blood flow to the head and heart
• blood flow from feet to heart work against gravity

Question 8

How does hydrostatic pressure vary throughout the circulatory system and with changes in the lying down body orientation?

Answer 8

• Hydrostatic pressure is more balanced because the gravitational impact is minimal.
• Aortic and right atrial pressure equalize, there is no significant resistance to overcome from gravity to circulate from blood from head to foot or heart to brain.

Question 9

How does resistance to blood flow affect blood pressure and tissue perfusion?

Answer 9

• if there isnt enough blood pressure to overcome resistance then there will be inadequate tissue perfusion

Question 10

Blood Flow

What is blood flow, and what factors are necessary for it to occur?

Answer 10

• movement of blood through vessels
• pressure gradient and resistance

Question 11

Blood Flow

What does the Basic Flow Equation (Ohm’s Law) describe about blood flow?

Answer 11

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Question 12

What are the components that affect resistance in a blood vessel, as described by Poiseuille’s Law?

Question 13

How do changes in vessel radius affect resistance and blood flow?

Question 14

What role do arterioles play in regulating blood flow and resistance?