1. BIOLOGY CONCEPTS & CONNECTIONS Fourth Edition Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Neil A. Campbell Jane B. Reece Lawrence G. Mitchell Martha R. Taylor From PowerPoint ® Lectures for Biology: Concepts & Connections CHAPTER 23 Circulation Modules 23.1 – 23.3

2. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings As with all land animals, the giraffe and the corn snake are constantly subject to the force of gravity How Does Gravity Affect Blood Circulation?

3. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The circulatory system keeps blood pumping despite gravity’s pull –Muscle contractions help blood travel uphill in the veins of a giraffe’s long legs –The wriggling of the corn snake squeezes its veins and increases circulation

4. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Most animals have a circulatory system –It transports O 2 and nutrients to cells –It takes away CO 2 and other wastes

5. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Capillaries are microscopic blood vessels –They form an intricate network among the tissue cells 23.1 The circulatory system associates intimately with all body tissues Figure 23.1A Red blood cell Capillary

6. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –No substance has to diffuse far to enter or leave a cell Figure 23.1B Capillary INTERSTITIAL FLUID Tissue cell Diffusion of molecules

7. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings In cnidarians and flatworms, the gastrovascular cavity functions in both –digestion –internal transport 23.2 Several types of internal transport have evolved in animals MECHANISMS OF INTERNAL TRANSPORT Figure 23.2A Mouth Circular canal

8. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Most animals have a separate circulatory system, either open or closed Open systems –A heart pumps blood through open-ended vessels into spaces between cells Figure 23.2B Pores Tubular heart

9. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Closed systems –A heart pumps blood through arteries and capillary beds –The blood returns to the heart via veins Figure 23.2C Artery (O 2 -rich blood) Arteriole Capillary beds Venule Vein Atrium Ventricle Heart Artery (O 2 -poor blood) Gill capillaries

10. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings A fish has a single circuit of blood flow 23.3 Vertebrate cardiovascular systems reflect evolution Figure 23.3A Gill capillaries Heart: Ventricle (V) Atrium (A) Systemic capillaries

11. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The cardiovascular system of land vertebrates has two circuits The pulmonary circuit –conveys blood between the heart and gas- exchange tissues The systemic circuit –carries blood between the heart and the rest of the body Figure 23.3B PULMONARY CIRCUIT A Systemic capillaries Lung capillaries V Right SYSTEMIC CIRCUIT A V Left