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 23.4 – 23.12

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The mammalian heart has two thin-walled atria that pump blood into the ventricles –The thick-walled ventricles pump blood to all other body organs 23.4 The human heart and cardiovascular system typify those of mammals THE MAMMALIAN CARDIOVACULAR SYSTEM

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 23.4A Pulmonary artery Superior vena cava RIGHT ATRIUM Pulmonary veins Semilunar valve Atrioventricular valve Inferior vena cava Aorta Pulmonary artery LEFT ATRIUM Pulmonary veins Semilunar valve Atrioventricular valve RIGHT VENTRICLE LEFT VENTRICLE

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 23.4B RIGHT VENTRICLE Capillaries of right lung 3 Capillaries of left lung 4 LEFT ATRIUM 5 LEFT VENTRICLE 6 Aorta 7 Capillaries of Head and arms 8 Capillaries of abdominal organs and legs 9 Superior vena cava 10 Inferior vena cava 11 RIGHT ATRIUM Pulmonary vein Aorta Pulmonary vein Pulmonary artery

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings A single layer of epithelial cells forms capillary walls Arteries and veins have smooth muscle and connective tissue –Valves in veins prevent the backflow of blood 23.5 The structure of blood vessels fits their functions

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 23.5 Epithelium Smooth muscle Connective tissue ARTERY ARTERIOLE CAPILLARY EpitheliumBasement membrane Epithelium Smooth muscle Connective tissue Valve VEIN VENULE

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Diastole –Blood flows from the veins into the heart chambers 23.6 The heart contracts and relaxes rhythmically Figure 23.6 Heart is relaxed. AV valves are open Atria contract. Ventricles contract. Semilunar valves are open. SYSTOLE DIASTOLE 0.4 sec 0.1 sec 0.3 sec Systole –The atria briefly contract and fill the ventricles with blood –Then the ventricles contract and propel blood out

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Heart valves prevent backflow Cardiac output –The amount of blood pumped into the aorta by the left ventricle per minute

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The SA node (pacemaker) generates electrical signals that trigger the contraction of the atria The AV node then relays these signals to the ventricles 23.7 The pacemaker sets the tempo of the heartbeat Figure 23.7 Pacemaker (SA node) 1234 Right atrium Right ventricle AV node Specialized muscle fibers ECG

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings An electrocardiogram (ECG) is a recording of electrical changes in the skin resulting from the electrical signals in the heart –Control centers in the brain adjust heart rate to body needs

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings A heart attack is damage that occurs when a coronary feeding the heart is blocked 23.8 Connection: What is a heart attack? Figure 23.8A Right coronary artery Aorta Left coronary artery Blockage Dead muscle tissue

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Blood vessel blockage is usually due to blood clots Figure 23.8B Connective tissue Smooth muscle EpitheliumPlaque

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Blood pressure depends on –cardiac output –resistance of vessels 23.9 Blood exerts pressure on vessel walls

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Pressure is highest in the arteries –It drops to zero by the time the blood reaches the veins Figure 23.9A Diastolic pressure Systolic pressure Relative sizes and numbers of blood vessels

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Three factors keep blood moving back to the heart –muscle contractions –breathing –one-way valves Figure 23.9B Direction of blood flow in vein Valve (closed) Skeletal muscle Valve (open)

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Blood pressure is measured as systolic and diastolic pressures Connection: Measuring blood pressure can reveal cardiovascular problems Figure Blood pressure 120 systolic 80 diastolic (to be measured) Rubber cuff inflated with air Pressure in cuff below 120 Pressure in cuff below 80 Artery Pressure in cuff above 120 Sounds audible in stethoscope Sounds stop Artery closed

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Hypertension is persistent systolic pressure higher than 140 mm Hg and/or diastolic pressure higher than 90 mm Hg –It is a serious cardiovascular problem

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Muscular constriction of arterioles and precapillary sphincters controls the flow through capillaries Smooth muscle controls the distribution of blood Figure Sphincters relaxed 2 Sphincters contracted Precapillary sphinctersThoroughfare channel Capillaries ArterioleVenuleArteriole Venule Thoroughfare channel

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Capillaries allow the transfer of substances through their walls Figure 23.12A

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The transfer of materials between the blood and interstitial fluid can occur by –leakage through clefts in the capillary walls –diffusion through the wall –blood pressure –osmotic pressure

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 23.12B Arterial end of capillary Tissue cells Osmotic pressure INTERSTITIAL FLUID NET PRESSURE OUT Blood pressure Osmotic pressure Venous end of capillary NET PRESSURE IN