The Heart: Regulation of Heart Rate Increased heart rate 1. Sympathetic nervous system Crisis Low blood pressure 2. Hormones Epinephrine Thyroxine 3. Exercise 4. Decreased blood volume Slide 11.21 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

The Heart: Regulation of Heart Rate Decreased heart rate 1. Parasympathetic nervous system 2. High blood pressure or blood volume 3. Decreased venous return Slide 11.22 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Major Arteries of Systemic Circulation Figure 11.11 Slide 11.30 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Major Veins of Systemic Circulation Figure 11.12 Slide 11.31 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Arterial Supply of the Brain Figure 11.13 Slide 11.32 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Hepatic Portal Circulation Figure 11.14 Slide 11.33 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Circulation to the Fetus Figure 11.15 Slide 11.34 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Blood Pressure Measurements by health professionals are made on the pressure in large arteries Systolic – pressure at the peak of ventricular contraction Diastolic – pressure when ventricles relax Pressure in blood vessels decreases as the distance away from the heart increases Slide 11.36 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Measuring Arterial Blood Pressure Figure 11.18 Slide 11.37 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Comparison of Blood Pressures in Different Vessels Figure 11.17 Slide 11.38 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Blood Pressure: Effects of Factors 1. Neural factors Autonomic nervous system adjustments (sympathetic division) 2. Renal factors Regulation by altering blood volume Renin – hormonal control Slide 11.39a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Blood Pressure: Effects of Factors 3. Temperature Heat has a vasodilation effect Cold has a vasoconstricting effect 4. Chemicals Various substances can cause increases or decreases 5. Diet Slide 11.39b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Variations in Blood Pressure Human normal range is variable Normal 120 mm Hg systolic 80 mm Hg diastolic Hypotension Low systolic (below 110 mm HG) Often associated with illness Hypertension High systolic (above 140 mm HG) Can be dangerous if it is chronic Slide 11.41 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Developmental Aspects of the Cardiovascular System A simple “tube heart” develops in the embryo and pumps by the fourth week The heart becomes a four-chambered organ by the end of seven weeks Few structural changes occur after the seventh week Slide 11.44 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings