1. 12 November 2010 Cardiovascular Physiology
Today’s lecture: MAP and TPR
Blood Vessels
Lab next week: Human Electrocardiography and Blood Pressure

2. 1QQ # 27 for 8:30 am
During isovolumetric contraction of the left ventricle
a) the mitral valve is open b) the aortic valve is closed
c) pressure in the left ventricle is greater than in the left atrium
d) pressure in the left ventricle is greater than in the aorta
e) the pressure is rising very rapidly in the left ventricle.
Acting via beta-adrenergic receptors, EPI will
Increase heart rate
Increase stroke volume
Increase ejection fraction
Increase the rate of tension development in cardiac myofibers
Increase twitch duration in cardiac myofibers.

3. 1QQ # 27 for 9:30 am
During isovolumetric relaxation of the left ventricle
a) the mitral valve is open b) the aortic valve is closed
c) pressure in the left ventricle is greater than in the left atrium
d) pressure in the left ventricle is greater than in the aorta
e) the pressure is rising very rapidly in the left ventricle.
Acting via muscarinic AChRs, acetylcholine will
Decrease heart rate
Increase stroke volume
Increase ejection fraction
Increase the rate of tension development in cardiac myofibers
Increase twitch duration in cardiac myofibers.

4. CO = HR x SV 5L/min = 72 beat/min x 70 ml/beat 35L/min =. beat/min x
CO = HR x SV 5L/min = 72 beat/min x 70 ml/beat 35L/min = ? beat/min x ? ml/beat
S 1
So far, we’ve dealt with the factors that control Cardiac Output by changing heart rate and stroke volume.

5. Summary of Factors that Regulate Cardiac Output
Fig
Even persons with heart transplants can adjust CO in the absence of innervation of heart.
12.28.jpg
Notice: No Parasymp innervation of Cardiac Myofibers, Parasymp to Conducting Cells only.

6. Heart is pump that generates pressure gradient.
Blood flows through vessels, which have resistance.
Arterioles have greatest resistance and create “backpressure” in the arteries and aorta.
Mean Arterial Pressure = diastolic +1/3(systolic – diastolic)
= /3(120-70) =
= 87 mm Hg

7. Mean Arterial Pressure = Cardiac Output x Total Peripheral Resistance
MAP = CO x TPR
MAP = (HR x SV) x TPR

8. Properties of Blood Vessels
All vessels and heart chambers lined with ENDOTHELIAL cells (simple squamous)
Arteries
Arterioles
Capillaries
Venules
Veins
Elastic, low compliance, large diameter, low resistance vessels
Resistance vessels
Exchange
Wall = simple squamous endothelium
Capacitance vessels, high compliance, low pressure, valves for unidirectional flow

9. Fig. 12.29 S 6 Aorta Brachial or Femoral artery
Damage to artery vs vein
Pusatile flow
12.29.jpg

10. 6
S 7
Fig b
Analogy: river width and flow
12.39b.jpg

11. S 8
Fig
Elastic recoil of stretched arterial walls during ventricular systole maintains arterial pressure during diastole as blood drains into arterioles.
Atherosclerosis
12.30.jpg
Point of Confusion: Smooth muscles in arterial walls DO NOT rhythmically contract!

12. Arteries and Arterial Pressure Mean Arterial Pressure
Arteriole
Arterioles have two main functions: 1) regulate flow to tissues and organs and 2) responsible for Total Peripheral Resistance which influences Blood Pressure.
MAP = CO x TPR
Poiseulle’s Equation

13. S 10
Fig
12.50.jpg

14. S 11
Receptors for other ligands
Alpha receptors more common except in skeletal muscle arterioles which have more B2 receptors