Martini’s Essentials of Anatomy and Physiology 8e brings a legacy of superb illustration and text–art integration with a suite of new digital tools The New Eighth edition takes the most popular features from the book and builds them out into effective interactives within the eText and Mastering A&P™ MARTINI / BARTHOLOMEW ESSENTIALS OF Anatomy & Physiology EIGHTH EDITION A01_MART3804_08_SE_WALK.indd 1 07/11/2018 09:28 Spotlight Figures Visually Summarize Difficult Physiological Processes, Making Them Easier to Understand These highly visual one- and two-page presentations of tough topics provide a bridge between readings and related figures and photos to communicate information in a student-friendly, visually effective format. Figure 8-9 SPOTLIGHT PROPAGATION OF AN ACTION POTENTIAL a a bb ContinuousContinuous Propagation Propagation AxonAxon hillock hillock SaltatorySaltatory Propagation Propagation 21 21 3 3 alongalong an an Unmyelinated Unmyelinated Axon Axon InitialInitial segment segment alongalong a a Myelinated Myelinated Axon Axon InIn an an unmyelinated unmyelinated axon, axon, an an action action potential potential moves moves BecauseBecause myelin myelin limits limits the the movement movement of of ions ions 11 22 33 alongalong by by continuous continuous propagation. propagation. The The action action acrossacross the the axon axon membrane, membrane, the the action action potentialpotential spreads spreads by by depolarizing depolarizing the the adjacent adjacent region region potentialpotential must must “jump” “jump” from from node node to to node node ofof the the axon axon membrane. membrane. This This process process continues continues to to duringduring propagation. propagation. This This results results in in much much spreadspread as as a achain chain reaction reaction down down the the axon. axon. fasterfaster propagation propagation along along the the axon. axon. KEYKEY ExtracellularExtracellular Fluid Fluid 11 ExtracellularExtracellular Fluid Fluid 11 ++ ++ AsAs an an action action potential potential develops develops ActionAction RestingResting membrane membrane AnAn action action potential potential +30+30 mV mV ++ ++ ++ –70–70 mV mV ++ ++ –70–70 mV mV ++ potentialpotential ++ ++ ++ ++ ++ atat the the initial initial segment segment 1 1, the, the +30+30 mV mV ++ –70–70 mV mV ++ –70–70 mV mV potentialpotential developsdevelops at at the the ++ ++ ++ ++ ++ ++ ++ ++ membranemembrane potential potential at at this this site site + + ++ ++ GradedGraded ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ NaNa ++ initialinitial segment segment 1 1 . + + ++ ++ depolarizationdepolarization ++ NaNa ++ depolarizesdepolarizes to to +30 +30 mV. mV. ++ ++ ++ ++ + + + + MyelinatedMyelinated ++ MyelinatedMyelinated ++ MyelinatedMyelinated RapidRapid 11 22 33 1 1 internodeinternode 2 2 internodeinternode 3 3 internodeinternode ––– ––– ––– ––– –––– – – depolarizationdepolarization ++ ++ ++ ++ ++ –– –––– – ––– –––– –––––– ––– ––– ––––– ––––– ++ ++ ++ CellCell membrane membrane CytosolCytosol RepolarizationRepolarization ++ ++ ++ ++++ ++ PlasmaPlasma membrane membrane CytosolCytosol GradedGraded depolarization depolarization 22 22 ++ ++ ++ AsAs the the sodium sodium ions ions entering entering at at AA local local current current ++ ++ –60–60 mV mV ++ –70–70 mV mV –60–60 mV mV –70–70 mV mV ++ ++ ++ ++ ++ ++ 1 1 spread spread away away from from the the open open ++ ++ ++ ++ ++ ++ producesproduces a a ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ voltage-gatedvoltage-gated channels, channels, a agraded graded gradedgraded ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ + + ++ ++ depolarizationdepolarization quickly quickly brings brings the the depolarizationdepolarization ++ ++ 11 22 33 ++ membranemembrane in in segment segment 2 2 to to –– –– –– ––– ––– –––– – – thatthat brings brings the the 1 1 2 2 3 3 ++ ++++ ++ ++ threshold.threshold. ++ axonaxon membrane membrane ++ ++ ++ ++LocalLocal––––––––––––––––––––––––––––––––++ –– –– ++ ++LoLo ++ ++ cacla cl ucrurerrnetnt atat the the next next node node ++ ++ ++ currentcurrent ++ toto threshold. threshold. RepolarizationRepolarization 33 33 ++ ++ ++ AnAn action action potential potential now now occurs occurs in in AnAn action action potential potential (refractory)(refractory) ++ ++ ++ RepolarizationRepolarization +30+30 mV mV ++ ++ –70–70 mV mV ++ ++ segmentsegment 2 2 while while segment segment 1 1 ++ ++ ++ ++ ++ (refractory)(refractory) +30+30 mV mV ++ –70–70 mV mV developsdevelops at at ++ ++ ++ ++ ++ ++ ++ ++ ++ beginsbegins repolarization. repolarization. ++ + + ++ nodenode 2 2. ++ ++ ++ ++ ++ ++ NaNa ++ NaNa+ + ++ ++ ++ ++ ++ ++ ++ ++ ++ 11 22 33 1 1 2 2 3 3 –– –– –– –––– – – –– –––– ++ ++++ ++++ –––––––––– ++ ++ –––––––––––––––––––––––– ++ ++ ++ ++ ++++++ ++ ++ ++ ++ ++++++++ 44 44 ++ ++ ++ ++ ++ AsAs the the sodium sodium ions ions entering entering at at AA local local current current ++ ++ –60–60 mV mV –60–60 mV mV ++ ++ ++ ++ ++ segmentsegment 2 2 spread spread laterally, laterally, a a producesproduces a agraded graded ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ gradedgraded depolarization depolarization quickly quickly ++ ++ ++ depolarizationdepolarization that that ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ ++ bringsbrings the the membrane membrane in in segment segment ++ bringsbrings the the axon axon ++ ++ ++ ++ 11 22 33 3 3 to to threshold, threshold, and and the the cycle cycle is is –––– –– membranemembrane at at node node 1 1 2 2 3 3 –– ++ L L++ –– ++ –––– – – repeated.repeated. ++ ocoaclal enetnt –––––––––––––––– ++ LocalLocal ++ –––––––––––––––– ++ ++++ ++ c ucrurrr 3 3 to to threshold. threshold. ++ ++ ++++ ++ ++ ++ ++ ++ ++currentcurrent ++ 256 257 M08_MART3804_08_SE_C08.indd 256 24/10/2018 21:06 M08_MART3804_08_SE_C08.indd 257 24/10/2018 21:06 A01_MART3804_08_SE_WALK.indd 2 07/11/2018 09:28 NEW Spotlight Figure Videos Bring This Effective Text Feature to Life NEW! 10 Spotlight Videos bring the popular in-text feature to life, with narrated, annotated guidance that walks students through some of toughest topics in A&P. Spotlight Video topics include: Inflammation and Regeneration, Synovial Joints, The Contraction Cycle, Refractive Problems, The Composition of Whole Blood, The Heart: Internal Anatomy and Blood Flow, Pulmonary Ventilation, Chemical Events in Digestion, A Summary of Kidney Function, and Regulation of Female Reproduction. SmartArt Video: Endochondral Ossication Watch the SmartArt Video for chapter 6, and then complete the question at right. Part A A hard ossied bone in an adult actually begins within the embryo as a miniature version composed of ____________. elastic cartilage hyaline cartilage dense regular connective tissue dense irregular connective tissue brocartilage Submit Request Answer Coaching Activities in Mastering A&P™ allow instructors to assign the videos to ensure students view them. A01_MART3804_08_SE_WALK.indd 3 07/12/18 2:31 PM Build Your Knowledge Integration Figures Emphasize That the Body Systems Work Together, Not in Isolation Build Your Knowledge Integration features show students how body systems affect each other and work together to maintain homeostasis. 636 URINARY SYSTEM Build Your Knowledge How the URINARY SYSTEM integrates with the other body systems presented so far Integumentary System Nervous System • The Integumentary System prevents • The Nervous System adjusts renal blood excessive fluid loss through skin surface; pressure; monitors distension of urinary produces vitamin D3, important for the bladder and controls urination renal production of calcitriol; sweat glands assist in elimination of water and solutes • The urinary system eliminates nitrogenous wastes; maintains fluid, electrolyte, and • The urinary system eliminates nitrogenous acid-base balance of blood, which is critical wastes; maintains fluid, electrolyte, and for neural function acid-base balance of blood that nourishes the skin Endocrine System Respiratory System • The Endocrine System produces aldosterone and ADH, which adjust rates of fluid and • The Respiratory System assists in the electrolyte reabsorption by kidneys regulation of pH by eliminating carbon dioxide • The urinary system releases renin when local blood pressure drops and erythropoietin • The urinary system assists in the elimination (EPO) when renal oxygen levels fall of carbon dioxide; provides bicarbonate buffers that assist in pH regulation Lymphatic System Cardiovascular System • The Lymphatic System provides adaptive (specific) defense against urinary tract • The Cardiovascular System delivers blood to infections glomerular capillaries, where filtration occurs; accepts fluids and solutes • The urinary system eliminates toxins and reabsorbed during urine production wastes generated by cellular activities; acid pH of urine provides innate (nonspecific) • The urinary system releases renin defense against urinary tract infections to elevate blood pressure and erythropoietin (EPO) to accelerate red blood cell production Digestive System Skeletal System • The Digestive System absorbs water needed to excrete wastes at kidneys; absorbs ions • The Skeletal System provides some needed to maintain normal body fluid protection for kidneys and ureters with its concentrations; liver removes bilirubin axial divison; pelvis protects urinary bladder and proximal portion of urethra • The urinary system excretes toxins absorbed by the digestive epithelium; excretes • The urinary system conserves calcium and bilirubin and nitrogenous wastes from the phosphate needed for bone growth liver; calcitriol production