Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings PowerPoint Lectures for Biology: Concepts and Connections, Fifth Edition – Campbell, Reece, Taylor, and Simon Lectures by Chris Romero Chapter 23 Circulation

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings How Does Gravity Affect Blood Circulation? Few animals seem less alike than the giraffe and the corn snake Despite their differences –They have many features in common

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Most animals have a circulatory system –That transports O 2 and nutrients to cells and takes away CO 2 and other wastes The circulatory system of land animals –Must deal with the problem of gravity

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 23.1 The circulatory system connects with all body tissues In many animals, microscopic blood vessels called capillaries –Form an intricate network among the tissue Capillary Nuclei of smooth muscle cells Red blood cell LM 700  Figure 23.1A

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Capillaries –Are the sites of exchange between blood and interstitial fluid Capillary Interstitial fluid Tissue cell Diffusion of molecules Figure 23.1B

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings MECHANISMS OF INTERNAL TRANSPORT 23.2 Several types of internal transport have evolved in animals In cnidarians and flatworms –The gastrovascular cavity functions in both digestion and internal transport Figure 23.2A Mouth Circular canal

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings In the open circulatory systems of arthropods and many molluscs –A heart pumps blood through open-ended vessels to bathe tissue cells directly Figure 23.2B Pores Tubular heart

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings In closed circulatory systems –A heart pumps blood through arteries to capillaries –Veins return blood to the heart Artery (O 2 -rich blood) Arteriole Capillary beds Venule Vein Atrium Ventricle Heart Artery (O 2 -poor blood) Gill capillaries Figure 23.2C

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 23.3 Vertebrate cardiovascular systems reflect evolution The two-chambered heart of a fish pumps blood in a single circuit –From gill capillaries to systemic capillaries and back to the heart Figure 23.3A Systemic capillaries Gill capillaries Heart: Ventricle (V) Atrium (A)

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Land vertebrates have double circulation –With separate pulmonary and systemic circuits

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Amphibians and reptiles –Have three-chambered hearts Figure 23.3B Pulmocutaneous circuit Systemic circuit RightLeft AA V Lung and skin capillaries Systemic capillaries

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Birds and mammals –Have four-chambered hearts Pulmonary circuit Systemic circuit Right Left AA V Lung capillaries Systemic capillaries V Figure 23.3C

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings THE MAMMALIAN CARDIOVACULAR SYSTEM 23.4 The human heart and cardiovascular system are typical of mammals The mammalian heart –Has two thin-walled atria that pump blood into the ventricles –Has thick-walled ventricles that pump blood to all other body organs Right atrium Left atrium Semilunar valve Semilunar valve Atrioventricular (AV) valve Atrioventricular (AV) valve Right ventricle Left ventricle Figure 23.4A

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Blood flow through the human cardiovascular system Figure 23.4B Superior vena cava Capillaries of head, chest, and arms Pulmonary artery Capillaries of left lung Pulmonary vein Aorta Left atrium Left ventricle Aorta Capillaries of abdominal region and legs Inferior vena cava Right ventricle Right atrium Pulmonary vein Capillaries of right lung Pulmonary artery

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 23.5 The structure of blood vessels fits their functions A single layer of epithelial cells –Forms the walls capillaries Arteries and veins –Have smooth muscle and connective tissue Figure 23.5 Capillary Epithelium Basement membrane Valve Epithelium Smooth muscle Connective tissue Vein Venule Arteriole Artery Connective tissue Smooth muscle Epithelium

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 23.6 The heart contracts and relaxes rhythmically During diastole –Blood flows from the veins into the heart chambers During systole –Contractions of the atria push blood into the ventricles –Stronger contractions of the ventricles propel blood into the large arteries

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings A cardiac cycle Figure 23.6 Heart is relaxed. AV valves are open. 1 2 Atria contract. Systole Diastole 0.4 sec 0.1sec 0.3 sec 3 Ventricles contract. Semilunar valves are open.

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Cardiac output –Is the amount of blood/minute pumped into the systemic circuit Heart valves –Prevent the backflow of blood

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 23.7 The pacemaker sets the tempo of the heartbeat The pacemaker (SA node) generates electrical signals –That trigger contraction of the atria The AV node –Relays these signals to the ventricles Figure Pacemaker (SA node) AV node Specialized muscle fibers Apex Right ventricle Right atrium ECG

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings An electrocardiogram (ECG) –Records the electrical changes in the heart Heart rate –Adjusts to body needs

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings CONNECTION 23.8 What is a heart attack? A heart attack is damage to cardiac muscle –Usually resulting from a blocked coronary artery Aorta Superior Vena cava Pulmonary artery Left coronary artery Right coronary artery Blockage Dead muscle tissue Figure 23.8A

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings In atherosclerosis –Plaques develop in the inner walls of arteries and can block blood flow Connective tissue Smooth muscle Epithelium LM 160  LM 60  Plaque Figure 23.8B

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 23.9 Blood exerts pressure on vessel walls Blood pressure –Is the force blood exerts on vessel walls –Depends on cardiac output and the resistance of vessels

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Pressure is highest in the arteries –And lowest in the veins Pressure is highest in the arteries –And lowest in the veins Figure 23.9A Pressure (mm Hg) Systolic pressure Diastolic pressure Relative sizes and numbers of blood vessels Velocity (cm/sec) Aorta Arteries Arterioles Capillaries Venules Venae cavae Vains

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Muscle contractions and one-way valves –Keep blood moving through the veins to the heart Skeletal muscle Direction of blood flow in vein Valve (open) Valve (closed) Figure 23.9B

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings CONNECTION Measuring blood pressure can reveal cardiovascular problems Blood pressure –Is measured as systolic and diastolic pressures Blood pressure 110 systolic 70 diastolic (to be measured) Rubber cuff inflated with air Artery Artery closed Pressure in cuff above Pressure in cuff at Pressure in cuff at Sounds stop Sounds audible in stethoscope Figure 23.10

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Hypertension –Is a serious cardiovascular problem

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Smooth muscle controls the distribution of blood Constriction of arterioles and precapillary sphincters –Controls blood flow through capillary beds Figure Sphincters relaxed Sphincters contracted VenuleArteriole Venule Arteriole Precapillary sphincters Thoroughfare channel Capillaries Thoroughfare channel

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Capillaries allow the transfer of substances through their walls TEM 5,000  Muscle cell Cleft between two epithelial cells of the capillary wall Nucleus of epithelial cell Capillary wall Iumen Interstitial fluid Figure 23.12A

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings The transfer of materials between the blood and interstitial fluid occurs –By diffusion –By pressure flow through clefts between epithelial cells Tissue cells Osmotic pressure Arterial end of capillary Interstitial fluid Net fluid Movement out Net fluid Movement in Blood pressure Blood pressure Osmotic pressure Venous end of capillary Figure 23.12B

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Blood pressure forces fluid out of the capillary at the arterial end –And osmotic pressure draws fluid at the venous end

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings STRUCTURE AND FUNCTION OF BLOOD Blood consists of red and white blood cells suspended in plasma Plasma is about 90% water –And contains various inorganic ions, proteins, nutrients, wastes, gases, and hormones Plasma (55%) Constituent Major functions Water Solvent for carrying other substances Salts (ions) Sodium Potassium Calcium Magnesium Chloride Bicarbonate Osmotic balance, pH buffering, and nerve and muscle function Plasma proteins Fibrinogen Immunoglobulins (antibodies) Osmotic balance and pH buffering Immunity Clotting Substances transported by blood Nutrients (e.g., glucose, fatty acids,vitamins) Waste products of metabolism Respiratory gases (O 2 and CO 2 ) Hormones Centrifuged blood sample Figure (left part)

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Red blood cells (erythrocytes) –Transport O 2 bound to hemoglobin White blood cells (leukocytes) –Function both inside and outside the circulatory system to fight infections and cancer Centrifuged blood sample Cellular elements (45%) Cell type Number per  L (mm 3 ) of blood Functions Erythrocytes (red blood cells) 5–6 million Transport of oxygen (and carbon dioxide) Leukocytes (white blood cells) 5,000–10,000 Defense and immunity Basophil Eosinophil Lymphocyte Monocyte Blood clotting250,000– 400,000 Platelets Neutrophil Figure (right part)

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings CONNECTION Too few or too many red blood cells can be unhealthy Anemia –Is an abnormally low amount of hemoglobin or red blood cells Colorized SEM 3,400  Figure 23.14

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings The hormone erythropoietin –Regulates red blood cell production Some athletes –Artificially increase their red blood cell production, a dangerous practice

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Blood clots plug leaks when blood vessels are injured When a blood vessel is damaged –Platelets help trigger the conversion of fibrinogen to fibrin, forming a clot that plugs the leak Colorized SEM 3,400  Figure 23.15B

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings The blood-clotting process Epithelium 1 Platelets adhere to exposed connective tissue Connective tissue Platelet Platelet plug 2 Platelet plug forms 3 Fibrin clot traps blood cells Figure 23.15A

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Stem cells offer a potential cure for blood cell diseases Stem cells divide in bone marrow –To produce all blood cells –And may be used to treat some blood disorders Figure 23.15B CONNECTION Stem cells Erythrocytes Basophils Eosinophils NeutrophilsMonocytes Lymphocytes Platelets