Questions and Answers
What physiological conditions can lead to functional murmurs?
Which of the following changes would have the most significant effect on total resistance (RT)?
If the total resistance (RT) is 100 and the resistance of the artery (RA) is increased to 4, what effect does this have on the total resistance?
Which statement correctly describes the relationship between the resistance of large arteries and total resistance (RT)?
Signup and view all the answers
In a scenario where Ra is increased to 280, how does this affect RT?
Signup and view all the answers
Which of the following scenarios is likely to produce a physiologic murmur?
Signup and view all the answers
How does the total resistance change when both RA and Ra are increased simultaneously?
Signup and view all the answers
What is the likely outcome when small arteries and arterioles regulate blood flow?
Signup and view all the answers
What resistance value is typically assigned to the capillaries (Rc) in the provided model?
Signup and view all the answers
What percentage decrease in the radius of a large distributing artery is necessary to significantly affect organ blood flow?
Signup and view all the answers
Which equation correctly represents the concept of compliance in blood vessels?
Signup and view all the answers
How does the compliance of combined veins compare to that of combined arteries?
Signup and view all the answers
What primarily determines diastolic pressure?
Signup and view all the answers
What effect does low compliance in the ventricle have on pressure changes?
Signup and view all the answers
What does shear stress depend on according to the given information?
Signup and view all the answers
Which factors are important in determining systolic pressure?
Signup and view all the answers
What anatomical feature could result in differential shear stress within an arterial segment?
Signup and view all the answers
How does increased preload affect cardiac output in a ventricle with low compliance?
Signup and view all the answers
Which factor leads to greater shear rates in blood flow?
Signup and view all the answers
Study Notes
Functional Murmurs
- Functional murmurs, or physiologic murmurs, occur without valvular disease.
- Aortic systolic ejection murmurs can arise from high cardiac output, leading to turbulent flow.
- Conditions causing high flow include exercise in trained athletes, anemia, and pregnancy.
- Increased blood flow can result in physiologic ejection murmurs especially during pregnancy.
Structure of Microcirculation
- Total resistance (RT) in microcirculation can be calculated as RT = RA + Ra + Rc + Rv + RV.
- Resistance values for each segment: RA = 1, Ra = 70, Rc = 20, Rv = 8, RV = 1.
- This results in RT = 100 for the given values.
- A four-fold increase in RA (to 4) leads to RT = 1.03(RT), causing only a 3% total resistance increase.
- A four-fold increase in Ra (to 280) raises RT to 310, resulting in a 210% increase.
- Small arteries and arterioles greatly influence total resistance compared to large arteries.
Blood Flow Regulation
- Changes in resistance in small arteries or arterioles have more impact on regulating organ blood flow than changes in large arteries.
- Significant reduction (over 60%-70%) in the radius of large arteries is necessary to affect organ blood flow.
Shear Stress and Viscosity
- Shear stress is calculated using the equation: Shear Stress = viscosity × Shear rate (velocity ratio of fluid layers).
- Shear rate distribution is greater at the edges of the lumen in blood vessels.
- Blood viscosity varies with shear rate, affecting blood flow dynamics.
Compliance of Blood Vessels
- Compliance indicates the ability of blood vessels to distend with volume changes, defined as C = ΔV / ΔP.
- Vascular compliance in veins is approximately 19 times greater than in arteries.
- Systolic pressure is influenced by stroke volume, preload, contractility, and compliance.
- Diastolic pressure is affected by heart rate, arteriolar resistance, and venous run-off.
- Low myocardial compliance leads to large pressure changes with small volume alterations, impairing cardiac output under increased preload.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge of cardiovascular physiology with this quiz focused on functional murmurs, microcirculation structures, and blood flow regulation. Explore concepts like total resistance in microcirculation and factors affecting physiologic murmurs. This quiz is perfect for students studying human physiology and related topics.
