New Spotlight Figure 13-7 Peripheral Distribution of Spinal Nerves Chapter 19: Blood New Figure 13-14 Neural Circuits: The Organization of Added information on aspirin as an anticoagulant Neuronal pools New Spotlight Figure 19-1 The Composition of Whole Blood New Figure 13-16 The Classification of Reflexes Figure 19-5 Recycling of Red Blood Cell Components revised Figure 13-21 The Babinski Reflex revised Figure 19-7 Blood Types and Cross-Reactions revised Clinical Note: Spinal Anesthesia revised Figure 19-8 Blood Type Testing revised New Spotlight Figure 19-9 Hemolytic Disease of the Newborn Chapter 14: The Brain and Cranial Nerves New Table 14-1 Development of the brain Figure 19-11 The Origins and Differentiation of Formed Elements revised Figure 14-5 The Diencephalon and Brain Stem revised New Figure 19-12 The Vascular, Platelet, and Coagulation Phases New Figure 14-7 The Cerebellum of hemostasis and lot retraction New Figure 14-12 The Brain in Lateral View Figure 14-16 Hemispheric Lateralization revised New Figure 14-17 Brain Wav Clinical Note: Epidural and Subdural Hemorrhages revised Chapter 20: The Heart Clinical Note: Aphasia and Dyslexia revised Figure 20-4 The Heart Wall revised Chapter 15: Neural Integration I: Sensory Pathways and the Somatic Figure 20-8 Valves of the Heart revised Nervous System Reorganized Section 15-4 Separate pathways carry somata Figure 20-12 Impulse Conduction through the Heart revised Figure 20-13 An Electrocardiogram revised sensory and visceral sensory information Figure 15-1 An Overview of Neural Integration revised New Spotlight Figure 20-14 Cardiac Arrhythmias Figure 20-15 The Action Potential in Skeletal and Cardiac Muscle Clinical note assessment of tactile sensitivities revised New Figure 20-16 Phases of the Cardiac Cycl New Figure 20-19 A Simple Model of Stroke Volume Chapter 16: Neural Integration Il: The Autonomic Nervous System and New Figure 20-20 Factors Affecting Cardiac Output Higher-Order Functions Figure 20-21 Autonomic Innervation of the Heart revised Enhanced Section 16-9 Neurotransmitters influence brain chemistry and behavior diac Output Figure 16-10 The Autonomic Plexuses and Ganglia revised Figure 16-12 A Comparison of Somatic and Autonomic Function Chapter 21: Blood Vessels and Circulation revised New Figure 16-14 Levels of Sleep New Figure 16-16 System Integrator Clinical Note: Amnesia revised New Figure 21-6 Valves in the Venous System Clinical Note: Alzheimer,s Disease revised New Figure 21-9 Factors Affecting Friction and Vascular Resistance Figure 21-10 Relationships among Vessel Diameter, Cross- Chapter 17: The Special Senses Sectional Area, Blood Pressure, and Blood Velocity revised Figure 17-1 The Olfactory Organs revised New Figure 21-14 Short-Term and Long-Term Cardiovascular New Spotlight Figure 17-2 Olfactory and Gustatory Receptors Figure 17-6 The Pupillary Muscles revised New Figure 21-15 Baroreceptor Reflexes of the Carotid and Figure 17-11 Accommodation revised Aortic Sinuses New Spotlight Figure 17-13 Accommodation Problems New Figure 21-16 The Chemoreceptor Reflexes New Spotlight Figure 17-17 Photoreception New Figure 21-17 Hormonal Regulation of Blood Pressure and New Figure 17-18 Bleaching and Regeneration of Visual Pigments Blood volume Figure 17-20 The Visual Pathways revised New Figure 21-18 Cardiovascular Responses to Hemorrhaging Figure 17-21 The Anatomy of the Ear revised and Blood loss Figure 17-30 Sound and Hearing revised Figure 21-19 A Schematic Overview of the Pattern of Circulation New Figure 17-32 Pathways for Auditory Sensations revised Clinical Note: Glaucoma revised New Figure 21-24 Arteries of the Brain Clinical Note: Motion Sickness revised Figure 21-25 Major Arteries of the Trunk revised Figure 21-26 Arteries Supplying the Abdominopelvic Organs Chapter 18: The Endocrine System revised New Spotlight Figure 18-2 Structural Classification of Hormones Figure 21-33 The Hepatic Portal System revised and brain Figure 18-1 Organs and Tissues of the Endocrine System revised New Figure 21-29 Major Veins of the Head, Figure 18-3 G Proteins and Hormone Activity revised New Spotlight Figure 21-35 Congenital Heart Problems Figure 18-13 The Homeostatic Regulation of Calcium lon New Figure 21-36 System Integrator Concentrations revised New Figure 18-15 The Pineal Gland Chapter 22: The Lymphatic System and Immunity Figure 18-17 The Regulation of Blood Glucose Concentrations New Figure 22-1 An Overview of the Lymphatic System: The Lymphatic Vessels, Lymphoid Tissues, and Lymphoid Organs New Spotlight Figure 18-18 Diabetes Mellitus New Figure 22-5 Classes of Lymphocytes Figure 18-19 Endocrine Functions of the Kidneys revised Figure 22-11 Innate Defenses revised New Spotlight Figure 18-20 The General Adaptation Syndrome Figure 22-12 How Natural Killer Cells Kill Cellular Targets revised New Figure 18-21 System Integrator New Figure 22-13 Interferons Clinical Note. Hormones and Athletic Performance revised New Figure 22-14 Pathways of Complement Activation
• New Spotlight Figure 13–7 Peripheral Distribution of Spinal Nerves • New Figure 13–14 Neural Circuits: The Organization of Neuronal Pools • New Figure 13–16 The Classification of Reflexes • Figure 13–21 The Babinski Reflex revised • Clinical Note: Spinal Anesthesia revised Chapter 14: The Brain and Cranial Nerves • New Table 14–1 Development of the Brain • Figure 14–5 The Diencephalon and Brain Stem revised • New Figure 14–7 The Cerebellum • New Figure 14–12 The Brain in Lateral View • Figure 14–16 Hemispheric Lateralization revised • New Figure 14–17 Brain Waves • Clinical Note: Epidural and Subdural Hemorrhages revised • Clinical Note: Aphasia and Dyslexia revised Chapter 15: Neural Integration I: Sensory Pathways and the Somatic Nervous System • Reorganized Section 15–4 Separate pathways carry somatic sensory and visceral sensory information • Figure 15–1 An Overview of Neural Integration revised • Figure 15–3 Tactile Receptors in the Skin revised • New Spotlight Figure 15–5 Somatic Sensory Pathways • Clinical Note: Assessment of Tactile Sensitivities revised Chapter 16: Neural Integration II: The Autonomic Nervous System and Higher-Order Functions • Enhanced Section 16–9 Neurotransmitters influence brain chemistry and behavior • Figure 16–10 The Autonomic Plexuses and Ganglia revised • Figure 16–12 A Comparison of Somatic and Autonomic Function revised • New Figure 16–14 Levels of Sleep • New Figure 16–16 System Integrator • Clinical Note: Amnesia revised • Clinical Note: Alzheimer’s Disease revised Chapter 17: The Special Senses • Figure 17–1 The Olfactory Organs revised • New Spotlight Figure 17–2 Olfactory and Gustatory Receptors • Figure 17–6 The Pupillary Muscles revised • Figure 17–11 Accommodation revised • New Spotlight Figure 17–13 Accommodation Problems • New Spotlight Figure 17–17 Photoreception • New Figure 17–18 Bleaching and Regeneration of Visual Pigments • Figure 17–20 The Visual Pathways revised • Figure 17–21 The Anatomy of the Ear revised • Figure 17–30 Sound and Hearing revised • New Figure 17–32 Pathways for Auditory Sensations • Clinical Note: Glaucoma revised • Clinical Note: Motion Sickness revised Chapter 18: The Endocrine System • Figure 18–1 Organs and Tissues of the Endocrine System revised • New Spotlight Figure 18–2 Structural Classification of Hormones • Figure 18–3 G Proteins and Hormone Activity revised • Figure 18–13 The Homeostatic Regulation of Calcium Ion Concentrations revised • New Figure 18–15 The Pineal Gland • Figure 18–17 The Regulation of Blood Glucose Concentrations revised • New Spotlight Figure 18–18 Diabetes Mellitus • Figure 18–19 Endocrine Functions of the Kidneys revised • New Spotlight Figure 18–20 The General Adaptation Syndrome • New Figure 18–21 System Integrator • Clinical Note: Hormones and Athletic Performance revised Chapter 19: Blood • Added information on aspirin as an anticoagulant • New Spotlight Figure 19–1 The Composition of Whole Blood • Figure 19–5 Recycling of Red Blood Cell Components revised • Figure 19–7 Blood Types and Cross-Reactions revised • Figure 19–8 Blood Type Testing revised • New Spotlight Figure 19–9 Hemolytic Disease of the Newborn • Figure 19–11 The Origins and Differentiation of Formed Elements revised • New Figure 19–12 The Vascular, Platelet, and Coagulation Phases of Hemostasis and Clot Retraction • Clinical Note: Plasma Expanders revised • Clinical Note: Abnormal Hemoglobin revised Chapter 20: The Heart • Figure 20–4 The Heart Wall revised • Figure 20–8 Valves of the Heart revised • New Spotlight Figure 20–10 Heart Disease and Heart Attacks • Figure 20–12 Impulse Conduction through the Heart revised • Figure 20–13 An Electrocardiogram revised • New Spotlight Figure 20–14 Cardiac Arrhythmias • Figure 20–15 The Action Potential in Skeletal and Cardiac Muscle revised • New Figure 20–16 Phases of the Cardiac Cycle • New Figure 20–19 A Simple Model of Stroke Volume • New Figure 20–20 Factors Affecting Cardiac Output • Figure 20–21 Autonomic Innervation of the Heart revised • New Figure 20–23 Factors Affecting Stroke Volume • Figure 20–24 A Summary of the Factors Affecting Cardiac Output revised Chapter 21: Blood Vessels and Circulation • Figure 21–2 Histological Structure of Blood Vessels revised • New Figure 21–4 Capillary Structure • New Figure 21–6 Valves in the Venous System • New Figure 21–9 Factors Affecting Friction and Vascular Resistance • Figure 21–10 Relationships among Vessel Diameter, CrossSectional Area, Blood Pressure, and Blood Velocity revised • New Figure 21–14 Short-Term and Long-Term Cardiovascular Responses • New Figure 21–15 Baroreceptor Reflexes of the Carotid and Aortic Sinuses • New Figure 21–16 The Chemoreceptor Reflexes • New Figure 21–17 Hormonal Regulation of Blood Pressure and Blood Volume • New Figure 21–18 Cardiovascular Responses to Hemorrhaging and Blood Loss • Figure 21–19 A Schematic Overview of the Pattern of Circulation revised • New Figure 21–24 Arteries of the Brain • Figure 21–25 Major Arteries of the Trunk revised • Figure 21–26 Arteries Supplying the Abdominopelvic Organs revised • New Figure 21–29 Major Veins of the Head, Neck, and Brain • Figure 21–33 The Hepatic Portal System revised • New Spotlight Figure 21–35 Congenital Heart Problems • New Figure 21–36 System Integrator Chapter 22: The Lymphatic System and Immunity • New Figure 22–1 An Overview of the Lymphatic System: The Lymphatic Vessels, Lymphoid Tissues, and Lymphoid Organs • New Figure 22–5 Classes of Lymphocytes • Figure 22–11 Innate Defenses revised • Figure 22–12 How Natural Killer Cells Kill Cellular Targets revised • New Figure 22–13 Interferons • New Figure 22–14 Pathways of Complement Activation viii Preface
Preface ix New Figure 22-15 Inflammation and the Steps in Tissue Repair New Figure 26-9 An Overview of urine Formation Figure 22-16 Forms of Immunity revised New Figure 26-10 Glomerular Filtration New Figure 22-17 An Overview of the Immune Response New Figure 26-11 The Response to a Reduction in the gFr New Figure 22-18 Antigens and MHC Proteins Figure 26-14 Tubular Secretion and Solute Reabsorption at the New Figure 22-19 Antigen Recognition by and Activation of DCT revised Cytotoxic T Cells New Figure 26-15 The Effects of ADH on the DCt and collecting Antigen Recognition and Activation of Help TCells New Spotlight Figure 26-16 Summary of Renal Function Figure 22-22 The Sensitization and Activation of B Cells New Figure 26-20 The Micturition Reflex New Figure 22-26 An Integrated Summary of the Immune Response New Figure 26-21 System Integrator New Spotlight Figure 22-28 Cytokines of the Immune System New Figure 22-30 System Integrator Chapter 27: Fluid, Electrolyte, and Acid-Base Balance New Figure 27-4 Fluid Shifts between the ICF and ECF Chapter 23: The Respiratory System New Figure 27-5 The Homeostatic Regulation of Normal Included information on spirometry Sodium lon Concentrations in Body Fluids Figure 23-7 The Gross Anatomy of the Lungs revised New Figure 27-6 The Integration of Fluid Volume Regulation New Figure 23-12 An Overview of the Key Steps in External and Sodium lon Concentrations in Body fluids Respiration New Figure 27-7 Major Factors Involved in Disturbances of Figure 23-13 Gas Pressure and Volume Relationshi Potassium balance Figure 23-16 The Respiratory Muscles revised New Figure 27-8 Three Classes of Acids that Can Threaten pH Figure 23-17 Pulmonary Volumes and Capacities revised Balance Figure 23-18 Henry's Law and the Relationship between New Figure 27-9 The Basic Relationship between Poo, and Solubility and Pressure revised Plasma pH Figure 23-23 Carbon Dioxide Transport in Blood revised New Figure 27-10 Buffer Systems in Body Fluids Figure 23-34 A Summary of the Primary Gas Transport New Figure 27-12 The Carbonic Acid-Bicarbonate Buffer System Mechanisms revised New Figure 27-13 Kidney Tubules and pH Regulation Figure 23-25 Basic Regulatory Patterns of Respiration revised New Figure 27-14 Interactions among the Carbonic Acid-Bicarbonate Buffer System and Compensatory Mechanisms New Figure 23-27 The Chemoreceptor Response to Changes in Pco, in the Regulation of Plasma pH New Figure 27-15 Respiratory Acid-Base Regulation New Figure 27-16 Responses to Metabolic Acidosis Chapter 24: The Digestive System New Figure 27-17 Metabolic Alkalosis Reorganized the section Control of Digestive Functions igure 27-18 A Diagnostic Chart for Suspected Acid-Base New Figure 24-1 The Components of the Digestive System Figure 24-4 Peristalsis revised Chapter 28: The Reproductive System New Figure 24-5 The Regulation of Digestive Activities Added information on straight tubules igure 24-8 Teeth revised Figure 28-7 Spermatogenesis revised Figure 24-11 The Swallowing Process revised New Spotlight Figure 28-12 Regulation of Male Reproduction Figure 24-13 The Stomach Lining revised Figure 28-15 Oogenesis revised New Figure 24-14 The Secretion of Hydrochloric Acid Figure 28-16 The Ovarian Cycle revised New Spotlight Figure 24-15 Regulation of Gastric Activity New Figure 28-21 The Histology of the Vagin igure 28-22 The Female Extemal Genitalia revised to include vestibular bulb and vestibular gland Gallbladder and Bile ducts Figure 28-24 Pathways of Steroid Hormone Synthesis in Males New Figure 24-22 Major Duodenal Hormones and Females revised New Figure 24-23 The Activities of Major Digestive Tract Hormones New Spotlight Figure 28-25 Regulation of Female Reproduction New Figure 24-26 The Defecation Reflex New F1 New Spotlight Figure 24-27 Chemical Events in Digestion New Figure 24-28 Digestive Secretion and Absorption of Water Chapter 29: Development and Inheritance New Figure 24-29 System Integrator Added information on Apgar score Figure 29-1 Fertilization revised Chapter 25: Metabolism and Energetics New Figure 29-4 The Inner Cell Mass and Gastrulation Included information on exercise as a mechanism for lowering Figure 29-5 Extraembryonic Membranes and Placenta Formation revised New Figure 25-2 Nutrient Use in Cellular Metabolism New Figure 29-10 Factors Involved in the Initiation of Labor and New Figure 25-8 Beta-Oxidation Delivery New Figure 25-9 Lipid Transport and utilization New Figure 29-12 The Milk Let-Down Refle New Figure 25-10 Amino Acid Catabolism and Synthesis New Figure 29-13 Growth and Changes in Body Form and New Spotlight Figure 25-11 Absorptive and Postabsorptive States Proportion New Figure 25-13 Caloric Expenditures for Various Activities New Figure 25-14 Mechanisms of Heat Transfer Punnett Squares Chapter 26: The Urinary Syster Figure 29-17 Crossing Over and Translocation revised Included information on the myogenic mechanism New Figure 29-18 Inheritance of an X-Linked Trait Figure 26-2 The Position of the Kidneys revised
• New Figure 22–15 Inflammation and the Steps in Tissue Repair • Figure 22–16 Forms of Immunity revised • New Figure 22–17 An Overview of the Immune Response • New Figure 22–18 Antigens and MHC Proteins • New Figure 22–19 Antigen Recognition by and Activation of Cytotoxic T Cells • New Figure 22–20 Antigen Recognition and Activation of Helper T Cells • Figure 22–22 The Sensitization and Activation of B Cells • New Figure 22–26 An Integrated Summary of the Immune Response • New Spotlight Figure 22–28 Cytokines of the Immune System • New Figure 22–30 System Integrator Chapter 23: The Respiratory System • Included information on spirometry • Figure 23–7 The Gross Anatomy of the Lungs revised • New Figure 23–12 An Overview of the Key Steps in External Respiration • Figure 23–13 Gas Pressure and Volume Relationships revised • Figure 23–16 The Respiratory Muscles revised • Figure 23–17 Pulmonary Volumes and Capacities revised • Figure 23–18 Henry’s Law and the Relationship between Solubility and Pressure revised • Figure 23–23 Carbon Dioxide Transport in Blood revised • Figure 23–34 A Summary of the Primary Gas Transport Mechanisms revised • Figure 23–25 Basic Regulatory Patterns of Respiration revised • New Spotlight Figure 23–26 Control of Respiration • New Figure 23–27 The Chemoreceptor Response to Changes in PCO2 • New Figure 23–29 System Integrator Chapter 24: The Digestive System • Included information on vomiting • Reorganized the section Control of Digestive Functions • New Figure 24–1 The Components of the Digestive System • Figure 24–4 Peristalsis revised • New Figure 24–5 The Regulation of Digestive Activities • Figure 24–8 Teeth revised • Figure 24–11 The Swallowing Process revised • Figure 24–13 The Stomach Lining revised • New Figure 24–14 The Secretion of Hydrochloric Acid • New Spotlight Figure 24–15 Regulation of Gastric Activity • Figure 24–16 Segments of the Intestine revised • New Figure 24–21 The Anatomy and Physiology of the Gallbladder and Bile Ducts • New Figure 24–22 Major Duodenal Hormones • New Figure 24–23 The Activities of Major Digestive Tract Hormones • New Figure 24–26 The Defecation Reflex • New Spotlight Figure 24–27 Chemical Events in Digestion • New Figure 24–28 Digestive Secretion and Absorption of Water • New Figure 24–29 System Integrator Chapter 25: Metabolism and Energetics • Included information on exercise as a mechanism for lowering cholesterol • New Figure 25–2 Nutrient Use in Cellular Metabolism • New Figure 25–8 Beta-Oxidation • New Figure 25–9 Lipid Transport and Utilization • New Figure 25–10 Amino Acid Catabolism and Synthesis • New Spotlight Figure 25–11 Absorptive and Postabsorptive States • New Figure 25–13 Caloric Expenditures for Various Activities • New Figure 25–14 Mechanisms of Heat Transfer Chapter 26: The Urinary System • Included information on the myogenic mechanism • Figure 26–2 The Position of the Kidneys revised • New Figure 26–9 An Overview of Urine Formation • New Figure 26–10 Glomerular Filtration • New Figure 26–11 The Response to a Reduction in the GFR • Figure 26–14 Tubular Secretion and Solute Reabsorption at the DCT revised • New Figure 26–15 The Effects of ADH on the DCT and Collecting Duct • New Spotlight Figure 26–16 Summary of Renal Function • New Figure 26–20 The Micturition Reflex • New Figure 26–21 System Integrator Chapter 27: Fluid, Electrolyte, and Acid–Base Balance • New Figure 27–4 Fluid Shifts between the ICF and ECF • New Figure 27–5 The Homeostatic Regulation of Normal Sodium Ion Concentrations in Body Fluids • New Figure 27–6 The Integration of Fluid Volume Regulation and Sodium Ion Concentrations in Body Fluids • New Figure 27–7 Major Factors Involved in Disturbances of Potassium Balance • New Figure 27–8 Three Classes of Acids that Can Threaten pH Balance • New Figure 27–9 The Basic Relationship between PCO2 and Plasma pH • New Figure 27–10 Buffer Systems in Body Fluids • New Figure 27–12 The Carbonic Acid–Bicarbonate Buffer System • New Figure 27–13 Kidney Tubules and pH Regulation • New Figure 27–14 Interactions among the Carbonic Acid–Bicarbonate Buffer System and Compensatory Mechanisms in the Regulation of Plasma pH • New Figure 27–15 Respiratory Acid–Base Regulation • New Figure 27–16 Responses to Metabolic Acidosis • New Figure 27–17 Metabolic Alkalosis • Figure 27–18 A Diagnostic Chart for Suspected Acid–Base Disorders revised Chapter 28: The Reproductive System • Added information on straight tubules • Figure 28–7 Spermatogenesis revised • New Spotlight Figure 28–12 Regulation of Male Reproduction • Figure 28–15 Oogenesis revised • Figure 28–16 The Ovarian Cycle revised • New Figure 28–21 The Histology of the Vagina • Figure 28–22 The Female External Genitalia revised to include vestibular bulb and vestibular gland • Figure 28–24 Pathways of Steroid Hormone Synthesis in Males and Females revised • New Spotlight Figure 28–25 Regulation of Female Reproduction • New Figure 28–26 System Integrator Chapter 29: Development and Inheritance • Added information on Apgar score • Figure 29–1 Fertilization revised • New Figure 29–4 The Inner Cell Mass and Gastrulation • Figure 29–5 Extraembryonic Membranes and Placenta Formation revised • New Figure 29–10 Factors Involved in the Initiation of Labor and Delivery • New Figure 29–12 The Milk Let-Down Reflex • New Figure 29–13 Growth and Changes in Body Form and Proportion • Figure 29–15 Major Patterns of Inheritance revised • New Figure 29–16 Predicting Phenotypic Characters by Using Punnett Squares • Figure 29–17 Crossing Over and Translocation revised • New Figure 29–18 Inheritance of an X-Linked Trait Preface ix
SPOTLIGHT ON Text-art integration botlikh Figure 10-11 DNEW Skeletal Muscle Innervation Spotlight figures are one- A single axon may branch has only one neurous or two-page presentations that combine text and art to communicate the neuron lies near the motor end plate of the muscle fiber physiological, organizational, or clinical information in a visually effective format. The cytoplasm of length of the ax CLear steps- combining text and art- s of the enzyme guide students through which breaks down Ach complex processes. More examples of text-art integration 三雅昏 The Contraction Cycle Synovial Joints Chapter 10, pages 294-295 Chapter 9, page 263
292 UNIT 1 Levels of Organization Neuromuscular junction Path of electrical impulse (action potential) Motor neuron Axon Synaptic terminal A single axon may branch to control more than one skeletal muscle fiber, but each muscle fiber has only one neuromuscular junction (NMJ). At the NMJ, the synaptic terminal of the neuron lies near the motor end plate of the muscle fiber. The synaptic cleft, a narrow space, separates the synaptic terminal of the neuron from the opposing motor end plate. The cytoplasm of the synaptic terminal contains vesicles filled with molecules of acetylcholine, or ACh. Acetylcholine is a neurotransmitter, a chemical released by a neuron to change the permeability or other properties of another cell’s plasma membrane. The synaptic cleft and the motor end plate contain molecules of the enzyme acetylcholinesterase (AChE), which breaks down ACh. The stimulus for ACh release is the arrival of an electrical impulse, or action potential, at the synaptic terminal. An action potential is a sudden change in the transmembrane potential that travels along the length of the axon. Junctional AChE fold of motor end plate Vesicles ACh Arriving action potential Myofibril SEE BELOW Sarcoplasmic reticulum Motor end plate Motor end plate 1 2 Figure 10–11 Spotlight Skeletal Muscle Innervation x Text-art integration SPOTLIGHT ON More examples of text-art integration: 1 2 3 4 5 6 Myosin Reactivation Myosin reactivation occurs when the free myosin head splits ATP into ADP and P. The energy released is used to recock the myosin head. Cross-Bridge Detachment When another ATP binds to the myosin head, the link between the myosin head and the active site on the actin molecule is broken. The active site is now exposed and able to form another cross-bridge. Cross-Bridge Formation Once the active sites are exposed, the energized myosin heads bind to them, forming cross-bridges. Active-Site Exposure Calcium ions bind to troponin, weakening the bond between actin and the troponin–tropomyosin complex. The troponin molecule then changes position, rolling the tropomyosin molecule away from the active sites on actin and allowing interaction with the energized myosin heads. Contraction Cycle Begins Myosin Head Pivoting The contraction cycle, which involves a series of interrelated steps, begins with the arrival of calcium ions within the zone of overlap. After cross-bridge formation, the energy that was stored in the resting state is released as the myosin head pivots toward the M line. This action is called the power stroke; when it occurs, the bound ADP and phosphate group are released. The entire cycle is repeated several times each second, as long as Ca2+ concentrations remain elevated and ATP reserves are sufficient. Calcium ion levels will remain elevated only as long as action potentials continue to pass along the T tubules and stimulate the terminal cisternae. Once that stimulus is removed, the calcium channels in the SR close and calcium ion pumps pull Ca2+ from the sarcoplasm and store it within the terminal cisternae. Troponin molecules then shift position, swinging the tropomyosin strands over the active sites and preventing further cross-bridge formation. Resting Sarcomere Contracted Sarcomere In the resting sarcomere, each myosin head is already “energized”—charged with the energy that will be used to power a contraction. Each myosin head points away from the M line. In this position, the myosin head is “cocked” like the spring in a mousetrap. Cocking the myosin head requires energy, which is obtained by breaking down ATP; in doing so, the myosin head functions as ATPase, an enzyme that breaks down ATP. At the start of the contraction cycle, the breakdown products, ADP and phosphate (often represented as P), remain bound to the myosin head. + + Myosin head Troponin Tropomyosin Actin Ca2+ ADP P ADP P Ca2+ ADP P + ADP P + ADP P + ADP P + Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Sarcoplasm Active site ADP P + ADP P + ADP + P ADP + P ATP ATP Zone of Overlap (shown in sequence above) 294 295 Figure 10–12 Spotlight The Contraction Cycle III II Manubrium Clavicle Ulna Humerus Movement: slight nonaxial or multiaxial Examples: • Acromioclavicular and claviculosternal joints • Intercarpal and intertarsal joints • Vertebrocostal joints • Sacro-iliac joints Movement: monaxial Examples: • Elbow joint • Knee joint • Ankle joint • Interphalangeal joint Synovial joints are described as gliding, hinge, pivot, condylar, saddle, or ball-and-socket on the basis of the shapes of the articulating surfaces. Each type permits a different range and type of motion. Gliding joint Hinge joint Atlas Axis Pivot joint Movement: monaxial (rotation) Examples: • Atlanto-axial joint • Proximal radio-ulnar joint Condylar joint Scaphoid bone Radius Ulna Movement: biaxial Examples: • Radiocarpal joint • Metacarpophalangeal joints 2–5 • Metatarsophalangeal joints Saddle joint Ball-and-socket joint Movement: biaxial Examples: • First carpometacarpal joint Movement: triaxial Examples: • Shoulder joint • Hip joint Trapezium Metacarpal bone of thumb Scapula Humerus 263 Figure 9–6 Spotlight Synovial Joints The Contraction Cycle Chapter 10, pages 294–295 Synovial Joints Chapter 9, page 263 NEW Spotlight figures are oneor two-page presentations that combine text and art to communicate physiological, organizational, or clinical information in a visually effective format. Clear steps— combining text and art— guide students through complex processes
DThe explanation is built rec tly into the illustration for efficient and effective ettects are arn a●a acts upon the motor end plate un hen the action potential ity changes in the membrane trigger th cytosis occurs synaptic cleft, thus inactivating e cell is very low, sodium ions DThe all-in-one-place presentation means no flipping back and forth the Diabetes Mellitus Generation of an Action potential Chapter 18, page 623 Chapter 12, pages 396-397
Muscle Fiber Na+ Na+ Na+ ACh receptor site AChE Motor end plate When the action potential reaches the neuron's synaptic terminal, permeability changes in the membrane trigger the exocytosis of ACh into the synaptic cleft. Exocytosis occurs as vesicles fuse with the neuron's plasma membrane. ACh molecules diffuse across the synaptic cleft and bind to ACh receptors on the surface of the motor end plate. ACh binding alters the membrane’s permeability to sodium ions. Because the extracellular fluid contains a high concentration of sodium ions, and sodium ion concentration inside the cell is very low, sodium ions rush into the sarcoplasm. The sudden inrush of sodium ions results in the generation of an action potential in the sarcolemma. AChE quickly breaks down the ACh on the motor end plate and in the synaptic cleft, thus inactivating the ACh receptor sites. Action potential The action potential generated at the motor end plate now sweeps across the entire membrane surface. The effects are almost immediate because an action potential is an electrical event that flashes like a spark across the sarcolemmal surface. The effects are brief because the ACh has been removed, and no further stimulus acts upon the motor end plate until another action potential arrives at the synaptic terminal. 3 4 5 xi The explanation is built directly into the illustration for efficient and effective learning. The all-in-one-place presentation means no flipping back and forth between narrative and illustration to get the full story. 2 3 4 – – + + + + + + + + + + + + – – – – – – – + + + + + + + + + + + + + + + + + + – – – – – – – – – + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + – – – – – – – + + + + + + + + + + + + + 1 2 3 4 1 + – – – – + + + + + + – + + + + + + + + Axon hillock Initial segment During the absolute refractory period, the membrane cannot respond to further stimulation. Activation of Sodium Channels and Rapid Depolarization When the sodium channel activation gates open, the plasma membrane becomes much more permeable to Na+. Driven by the large electrochemical gradient, sodium ions rush into the cytoplasm, and rapid depolarization occurs. The inner membrane surface now contains more positive ions than negative ones, and the transmembrane potential has changed from –60 mV to a positive value. The axolemma contains both voltagegated sodium channels and voltage-gated potassium channels that are closed when the membrane is at the resting potential. During the relative refractory period, the membrane can respond only to a largerthan-normal stimulus. DEPOLARIZATION REPOLARIZATION Threshold Transmembrane potential (mV) Resting potential Time (msec) Potassium channels close, and both sodium and potassium channels return to their normal states. Sodium channels close, voltagegated potassium channels open, and potassium ions move out of the cell. Repolarization begins. Each neuron receives information in the form of graded potentials on its dendrites and cell body, and graded potentials at the synaptic terminals trigger the release of neurotransmitters. However, the two ends of the neuron may be a meter apart, and even the largest graded potentials affect only a tiny area. Such relatively long-range communication requires a different mechanism—the action potential. Action potentials are propagated changes in the transmembrane potential that, once initiated, affect an entire excitable membrane. Whereas the resting potential depends on leak channels and the graded potential we considered depends on chemically gated channels, action potentials depend on voltage-gated channels. Steps in the formation of an action potential at the initial segment of an axon. The first step is a graded depolarizaton caused by the opening of chemically gated sodium ion channels, usually at the axon hillock. Note that when illustrating action potentials, we can ignore both the leak channels and the chemically gated channels, because their properties do not change. A graded depolarization brings an area of excitable membrane to threshold (–60 mV). Changes in the transmembrane potential at one location during the generation of an action potential. The circled numbers in the graph correspond to the steps illustrated below. Closing of Potassium Channels The voltage-gated sodium channels remain inactivated until the membrane has repolarized to near threshold levels. At this time, they regain their normal status: closed but capable of opening. The voltage-gated potassium channels begin closing as the membrane reaches the normal resting potential (about –70 mV). Until all of these potassium channels have closed, potassium ions continue to leave the cell. This produces a brief hyperpolarization. Inactivation of Sodium Channels and Activation of Potassium Channels As the transmembrane potential approaches +30 mV, the inactivation gates of the voltage-gated sodium channels close. This step is known as sodium channel inactivation, and it coincides with the opening of voltage-gated potassium channels. Positively charged potassium ions move out of the cytosol, shifting the transmembrane potential back toward resting levels. Repolarization now begins. As the voltage-gated potassium channels close, the transmembrane potential returns to normal resting levels. The action potential is now over, and the membrane is once again at the resting potential. +30 –60 –40 –70 0 Voltage-gated sodium channels open and sodium ions move into the cell. The transmembrane potential rises to +30 mV. ABSOLUTE REFRACTORY PERIOD RELATIVE REFRACTORY PERIOD –70 mV +10 mV KEY = Sodium ion = Potassium ion –90 mV +30 mV –70 mV 0 1 2 –60 mV Local current Depolarization to Threshold The stimulus that initiates an action potential is a graded depolarization large enough to open voltage-gated sodium channels. The opening of the channels occurs at a transmembrane potential known as the threshold. Resting Potential Resting Potential 396 397 Figure 12-14 Spotlight Generation of an Action Potential Diabetes Mellitus Chapter 18, page 623 Generation of an Action Potential Chapter 12, pages 396–397
SPOTLIGHT ON Easy Readability )Topic headings are full sentences so students can learn 10-2 A skeletal muscle contains something about new topics just by muscle tissue, connective tissues, reading the headings. blood vessels, and nerves Figure 10-1 illustrates the organization of a representative skeletal muscle. Here we consider how connective tissues are organized in skeletal muscle, and how skeletal musdes are sup. DTopic headings correlate by number plied with blood vessels and nerves. In the next section we ex- ne skeletal muscle tissue in detail with HAPS-based Learning Outcomes on the Organization of Connective Tissues hapter-opening page for easy assessment. The Learning As you can see in Figure 10-1, each muscle has three layers of Outcomes are derived from those recommended by the Human connective tissue: (1)an epimysium,(2)a perimysium,and Anatomy and Physiology Society(HAPS). The Learning (3)an endomysium Outcomes are also tied directly to assessment in MasteringA&P The epimysium(ep-i-MIZ-e-um; epi-, on mys, muscle)is (www.masteringaandp.comandtheTestBank a dense layer of collagen fibers that surrounds the entire mus- cle. It separates the muscle from nearby tissues and organs. It is connected to the deep fascia, a dense connective tissue layer. The perimysium(per-i-MIZ-e-um; peri-, around) divides the skeletal muscle into a series of compartments. Each com- partment contains a bundle of muscle fibers called a fascicle MOre visual Clinical Note normal Bone development Clinical notes draw Giants and dwarfs -it all comes Q students'attention to clinical down to bones and distinction, the characteristic body p information they will need cartilage in their future careers (Flgure G-l4al, inadequate production of growth hormone Figure 6-14 Examples of Abnormal Bone Development leads to reduced epiphyseal cartilage Other examples of easy-to-read features System Integrators Easy-to-read tables Chapter 21, page 759 Chapter 4, page 131
xii Other examples of easy-to-read features: The CARDIOVASCULAR System Delivers immune system cells to injury sites; clotting response seals breaks in skin surface; carries away toxins from sites of infection; provides heat Transports calcium and phosphate for bone deposition; delivers EPO to red bone marrow, parathyroid hormone, and calcitonin to osteoblasts and osteoclasts Delivers oxygen and nutrients, removes carbon dioxide, lactic acid, and heat during skeletal muscle activity Endothelial cells maintain blood–brain barrier; helps generate CSF Distributes hormones throughout the body; heart secretes ANP and BNP Stimulation of mast cells produces localized changes in blood flow and capillary permeability Provides calcium needed for normal cardiac muscle contraction; protects blood cells developing in red bone marrow Skeletal muscle contractions assist in moving blood through veins; protects superficial blood vessels, especially in neck and limbs Controls patterns of circulation in peripheral tissues; modifies heart rate and regulates blood pressure; releases ADH Erythropoietin regulates production of RBCs; several hormones elevate blood pressure; epinephrine stimulates cardiac muscle, elevating heart rate and contractile force The section on vessel distribution demonstrated the extent of the anatomical connections between the cardiovascular system and other organ systems. This figure summarizes some of the physiological relationships involved. The most extensive communication occurs between the cardiovascular and lymphatic systems. Not only are the two systems physically interconnected, but cells of the lymphatic system also move from one part of the body to another within the vessels of the cardiovascular system. We examine the lymphatic system in detail, including its role in Muscular Integumentary Skeletal Nervous Endocrine Integumentary Page 000 Skeletal Page 000 Muscular Page 000 Nervous Page 000 Endocrine Page 000 Lymphatic Page 000 Respiratory Page 000 Digestive Page 000 Urinary Page 000 Reproductive Page 000 SYSTEM INTEGRATOR Body System Cardiovascular System Cardiovascular System Body System Figure 21–36 diagrams the functional relationships between the cardiovascular system and the other body systems we have studied so far. System Integrators Chapter 21, page 759 Easy Readability Topic headings correlate by number with HAPS-based Learning Outcomes on the chapter-opening page for easy assessment. The Learning Outcomes are derived from those recommended by the Human Anatomy and Physiology Society (HAPS). The Learning Outcomes are also tied directly to assessment in MasteringA&P (www.masteringaandp.com) and the Test Bank. More visual Clinical Notes draw students’ attention to clinical information they will need in their future careers. Easy-to-read tables Chapter 4, page 131 SPOTLIGHT ON Topic headings are full sentences so students can learn something about new topics just by reading the headings. Giants and dwarfs —it all comes down to bones and cartilage A variety of endocrine or metabolic problems can result in characteristic skeletal changes. In pituitary dwarfism (Figure 6–14a), inadequate production of growth hormone leads to reduced epiphyseal cartilage activity and abnormally short bones. This condition is becoming increasingly rare in the United States, because children can be treated with synthetic human growth hormone. Gigantism results from an overproduction of growth hormone before puberty. (The world record for height is 272 cm, or 8 ft, 11 in., reached by Robert Wadlow, of Alton, Illinois, who died at age 22 in 1940. Wadlow weighed 216 kg, or 475 lb.) If growth hormone levels rise abnormally after epiphyseal cartilages close, the skeleton does not grow longer, but bones get thicker, especially those in the face, jaw, and hands. Cartilage growth and alterations in soft-tissue structure lead to changes in physical features, such as the contours of the face. These physical changes occur in the disorder called acromegaly. Several inherited metabolic conditions that affect many systems influence the growth and development of the skeletal system. These conditions produce characteristic variations in body proportions. For example, many individuals with Marfan’s syndrome are very tall and have long, slender limbs (Figure 6–14b), due to excessive cartilage formation at the epiphyseal cartilages. Although this is an obvious physical distinction, the characteristic body proportions are not in themselves dangerous. However, the underlying mutation, which affects the structure of connective tissue throughout the body, commonly causes life-threatening cardiovascular problems. Clinical Note Abnormal Bone Development a Pituitary dwarfism b Marfan’s syndrome Figure 6–14 Examples of Abnormal Bone Development. 10-2 ◗ A skeletal muscle contains muscle tissue, connective tissues, blood vessels, and nerves Figure 10–1 illustrates the organization of a representative skeletal muscle. Here we consider how connective tissues are organized in skeletal muscle, and how skeletal muscles are supplied with blood vessels and nerves. In the next section we examine skeletal muscle tissue in detail. Organization of Connective Tissues As you can see in Figure 10–1, each muscle has three layers of connective tissue: (1) an epimysium, (2) a perimysium, and (3) an endomysium. The epimysium ( ; epi-, on mys, muscle) is a dense layer of collagen fibers that surrounds the entire muscle. It separates the muscle from nearby tissues and organs. It is connected to the deep fascia, a dense connective tissue layer. The perimysium ( ; peri-, around) divides the skeletal muscle into a series of compartments. Each compartment contains a bundle of muscle fibers called a fascicle per-i-MIZ-e -um ep-i-MIZ-e -um