othersmk_brs physiology 5th

1、457565837PPhy4s5756i58o37qlq.coomgyLinda S. Costanzo,Ph.D.Professor of Physiology and Biophysics Medical College of VirginiaVirginia Commonwealth University Richmond, VirginiaAcquisitions Editor: Crystal Taylor Product Manager: Stacey L. Sebring Designer:

2、 Holly Reid McLaughlinCompositor: MPS Limited, A Macmillan CompanyCopyright 2011 Lippincott Williams & WilkinsTwo Commerce Square 2001 Market StreetPhiladelphia, PA 19103Allrightsreserved. This bookisprotected bycopyright. Nopart of this book may bereproduced in any form or by any means, includingph

3、otocopying, orutilized by any information storage and retrieval system without written permission from the copyright owner.The publisher is not res4po5n7s5ib6le5(8as3a7matqteqr .ocfopmroduct liability, negligence, or otherwise) for anyinjury resulting from any material contained herein. This publica

4、tion contains information relating to general principles of medical care that should not be construed as specific instructions for individualpatients. Manufacturers product information and package inserts should be reviewed for current infor- mation, including contraindications, dosages, and precaut

5、ions.Printed in ChinaFirst Edition, 1995Second Edition, 1998Third Edition, 2003Fourth Edition, 2007Library of Congress Cataloging-in-Publication DataCostanzo, Linda S., 1947- Physiology/Linda S. Costanzo. 5th ed.p. ; cm. (Board review series)Includes bibliographical references and index. ISBN 978-0-

6、7817-9876-1 (alk. paper)1. Human physiologyExaminations, questions, etc. I. Title. II. Series: Board review series. DNLM: 1. Physiological PhenomenaExamination Questions. 2. PhysiologyExamination Questions. QT 18.2 C838p2011QP40.C67 2011 612.0076dc222010018984The publishers have madeeveryefforttotra

7、ce the copyright holders forborrowedmaterial. Ifthey have inadvertently overlooked any, they will be pleased to make the necessary arrangements at the first opportunity.Topurchase additional copies of this book, call our customer service department at (800) 638-3030or fax orders to (301) 223-2320. I

8、nternational customers should call (301) 223-2300.Visit Lippincott Williams & Wilkins on the Internet: http:/www.LWW.com. Lippincott Williams & Wilkins customer service representatives are available from 8:30 am to 6:00 pm, EST.1 2 3 4 5 6 7 8 9 10For RichardAndfor Dan and R4575

9、65837The subject matterof physiology is the foundation ofthe practice ofmedicine, and a firm grasp ofits principles is essential for the physician. This book is intended to aidthe student preparing for the United States Medical Licensing Examination (USMLE) Step 1. It is a conc4i5se75re6v5ie8w

10、37of kqeqy.pcohymsiologic principles and is intended to help thestudent recall material taught during the first and second years of medical school. It is not intended to substitute for comprehensive textbooks or for course syllabi, although the student may find it a useful adjunct to physiology and

11、pathophysiology courses.The material is organized by organ system into seven chapters. The first chapter reviews general principles of cellular physiology. The remaining six chapters review the major organ systemsneurophysiology, cardiovascular, respiratory, renal and acidbase, gastrointestinal, and

12、 endocrine physiology.Difficult concepts are explained stepwise, concisely, and clearly, with appropriate illustrative examples and sample problems. Numerous clinical correlations are included so that the student can understand physiology in relation to medicine. An integrative approach is used, whe

13、n possible, to demonstrate how the organ systems work together to maintain homeostasis. More than 130 full-color illustrations and flow diagrams and more than 50 tables help the student visualize the material quickly and aid in long-term retention. The inside front cover contains “Key Physiology Top

14、ics for USMLE Step 1.” The inside back cover contains “Key Physiology Equations for USMLE Step 1.”Questionsreflecting the contentand formatofUSMLEStep 1 are included atthe end of each chapter and in a Comprehensive Examination at the end of the book. These questions, many with clinical relevance, re

15、quire problem-solving skills rather than straight recall. Clear, concise explanations accompany the questions and guide the student through the correct steps of reasoning. The questions can be used as a pretest to identify areas of weakness or as a post test to determine mastery. Special attention s

16、hould be given to the Comprehensive Examination, because its questions integrate several areas of physiology and related concepts of pathophysiology and pharmacology.New to this edition: Addition of new full-color figures Updated organization and text Expanded coverage of cellular, respiratory, rena

17、l, gastrointestinal, and endocrine physiology Increased emphasis on pathophysiologyBest of luck in your preparation for USMLE Step 1!Linda S. Costanzo, Ph.D.viiPrefaceIthas been apleasureto be a partof the BoardReviewSeries and to workwiththe staff at Lippincott Williams & Wilkins. Crystal Taylorand

18、 Stacey Sebring provided expert edi- torial assistance. Matthew Chansky again served as illustrator, revising and colorizing existing figures and creating new ones.My sincere thanks to students in the School of Medicine at Virginia Commonwealth University/Medical College of Virginia, who have provid

19、ed so many helpful suggestions for BRS Physiology. Thanks also to the many students from other medical schools who have taken the time to write to me about their experiences with this book.Linda S. Costanzo, Ph.D.ixAcknowledgmentsPreface vii Acknowledgments ix1.CELL PHYSIOLOGY1Cell Membranes 1 Trans

20、portAcross CellMembranes 2 Osmosis 5Diffusion Potential, Resting Membrane Potential, and Action Potential 7Neuromuscular and Synaptic Transmission 12 Skeletal Muscle 16Smooth Muscle 20Comparison of Skeletal Muscle, Smooth Muscle, and Cardiac Muscle 22I.II. III. IV.V.VI. VII. VIII.Review Test 232.NEU

21、ROPHYSIOLOGY31I. Autonomic Nervous System 31II. Sensory Systems 35III. Motor Systems 47IV. Higher Functions of the Cerebral Cortex 53V. BloodBrain Barrier and Cerebrospinal Fluid 54VI. Temperature Regulation 55Review Test 573.CARDIOVASCULAR PHYSIOLOGY64I. Circuitry of the Cardiovascular System 64II.

22、 Hemodynamics 64III. Cardiac Electrophysiology 69IV. Cardiac Muscle and Cardiac Output 74xiContentsContentsxiiCardiac Cycle 83Regulationof Arterial Pressure 85 Microcirculation and Lymph 89 Special Circulations 92Integrative Functions ofthe Cardiovascular System: Gravity, Exercise, and Hemorrhage 95

23、V.VI. VII. VIII. IX.Review Test 1004.RESPIRATORY PHYSIOLOGY113Lung Volumes and Capacities 113 Mechanics of Breathing 115 Gas Exchange 122Oxygen Transport 123CO2 Transport 128Pulmonary Circulation 129V/Q Defects 131Control of Breathing 132Integrated Responses of the Respiratory System 134I.II. III. I

24、V.V.VI. VII. VIII. IX.Review Test 1365.RENAL AND ACIDBASE PHYSIOLOGY144Body Fluids 144Renal Clearance, Renal Blood Flow, and Glomerular Filtration Rate 148 Reabsorption and Secretion 152NaCl Regulation 155K Regulation 159I.II. III. IV.V.VI. VII. VIII. IX.X.XI.Renal Regulation of Urea, Phosphate, Cal

25、cium, and Magnesium Concentration and Dilution of Urine 163Renal Hormones 168AcidBase Balance 168Diuretics 177Integrative Examples 177162Review Test 1806.GASTROINTESTINAL PHYSIOLOGY190I. Structure and Innervation of the Gastrointestinal Tract 190II. Regulatory Substances in the Gastrointestinal Trac

26、t 191III. Gastrointestinal Motility 195IV. Gastrointestinal Secretion 199V. Digestion and Absorption 209VI. Liver Physiology 214Review Test 216Contentsxiii7.ENDOCRINE PHYSIOLOGY222Overview of Hormones 222Cell Mechanisms and Second Messengers 224 Pituitary Gland (Hypophysis) 227Thyroid Gland 232Adren

27、al Cortex and Adrenal Medulla 235 Endocrine PancreasGlucagon and Insulin 242Calcium Metabolism (Parathyroid Hormone, Vitamin D, Calcitonin) 245Sexual Differentiation 249Male Reproduction 250Female Reproduction 253I.II. III. IV.V.VI. VII.VIII.IX.X.Review Test 257Comprehensive Examination 265Index2871

28、Cell PhysiologychapterI. CELL MEMBRANES are composed primarily of phospholipids and proteins.A. Lipid bilayer1. Phospholipids have a glycerol backbone, which is the hydrophilic (water-soluble) head, and two fatty acid tails, which are hydrophobic (water-insoluble). The hydrophobic tails face each ot

29、her and form a bilayer.2. Lipid-soluble substances (e.g., O2, CO2, steroid hormones) cross cell membranes because they can dissolve in the hydrophobic lipid bilayer.3. Water-soluble substances (e.g., Na+, Cl, glucose, H2O) cannot dissolve inthelipid of the membrane, but may cross through water-fille

30、d channels, or pores, or may be transport- ed by carriers.B.Proteins1. Integral proteins are anchored to, and imbedded in, the cell membrane through hydrophobicinteractions. may span the cell membrane. include ion channels, transport proteins, receptors, and guanosine 5-triphosphate (GTP)-binding pr

31、oteins (G proteins).2. Peripheral proteins are not imbedded in the cell membrane. are not covalently bound to membrane components. are loosely attached to the cell membrane by electrostatic interactions.Intercellular connections1. Tight junctions (zonula occludens) are the attachments between cells

32、(often epithelial cells). may be an intercellular pathway for solutes, depending on the size, charge, and char- acteristics of the tight junction. may be “tight” (impermeable), as inthe renal distal tubule, or “leaky” (permeable), as in the renal proximal tubule and gallbladder.2. Gap junctions are

33、the attachments between cells that permit intercellular communication. for example, permit current flow and electrical coupling between myocardial cells.C.12Board Review Series: Physiology t a b l e 1-1Characteristics of Different Typesof TransportNa+ GradientElectrochemical GradientCarrier- Mediate

34、dMetabolic EnergyInhibition of Na+K+ PumpTypeSimple diffusionDownhillNoNoNoInhibits (if Na+ K+ pump)Primary active transportUphillYesYesCountertransportUphill*YesIndirectYes, oppositedirectionInhibits*One or more solutes are transported uphill; Na+ is transported downhill.II. TRANSPORT ACROSS CELL M

35、EMBRANES (TABLE 1.1)A. Simple diffusion1. Characteristics of simple diffusion is the only form of transport that is not carrier-mediated. occurs down an electrochemical gradient (“downhill”). does not require metabolic energy and therefore is passive.2. Diffusion can be measured using the following

36、equation:J PA (C1 C2 )where:J= flux(flow)(mmol/sec) P= permeability (cm/sec) A = area (cm2)C1 = concentration1 (mmol/L) C2 = concentration2 (mmol/L)Sample calculation for diffusion The urea concentration of blood is 10 mg/100 mL. The urea concentration of prox- imal tubular fluid is 20 mg/100 mL. If

37、 the permeability to urea is 1 105 cm/ sec and the surface area is 100 cm2, what are the magnitude and direction of the urea flux?3. 1 10-5cm 20 mg- 10 mg (100 cm)Flux =2100 mL100 mL sec1 1-05 cm= 10 mg (100 cm)2100 mL sec 1 10 cm -5 0.1 mg (100 cm)=2 cm3 sec= 1 10-4 mg/sec from lumen to blood (high

38、 to low concentration)Note: The minus sign preceding the diffusion equation indicates thatthe direction of flux, or flow, isfrom high tolow concentration. It can be ignored ifthe higher concen- tration is called C1 and the lower concentration is called C2.Also note: 1 mL = 1 cm3.CotransportUphill*Ye

39、sIndirectYes,same directionInhibitsFacilitated diffusionDownhillYesNoNo Chapter 1 Cell Physiology34. Permeability is the P in the equation for diffusion. describes the ease with which a solute diffuses through a membrane. depends on the characteristics of the solute and the membrane.a. Factors that

40、increase permeability: Oil/water partition coefficient of the solute increases solubility in the lipid of the membrane. Radius(size) of the solute increasesthe diffusioncoefficientand speed of diffusion. Membrane thickness decreases the diffusion distance.b. Small hydrophobic solutes (e.g., O2) have

41、 the highest permeabilities in lipid membranes.c. Hydrophilic solutes (e.g., Na+) must cross cell membranes through water-filled chan-nels, or pores. Ifthe solute is an ion(is charged), thenitsflux will depend on both the concentration difference and the potential difference across the membrane.B. C

42、arrier-mediated transport includes facilitated diffusion and primary and secondary active transport. The characteristics of carrier-mediated transport are:1. Stereospecificity. For example, D-glucose (the natural isomer) is transported by facilitat- ed diffusion, but the L-isomer is not. Simple diff

43、usion, in contrast, would not distinguish between the two isomers because it does not involve a carrier.2. Saturation. The transport rate increases as the concentration of the solute increases, until the carriers are saturated. The transport maximum (Tm) is analogous to the maximum velocity (Vmax) i

44、n enzyme kinetics.3. Competition. Structurally related solutes compete for transport sites on carrier mole-cules. For example, galactose is a competitive inhibitor of glucose transport in the small intestine.C. Facilitated diffusion1. Characteristics of facilitated diffusion occurs down an electroch

45、emical gradient (“downhill”), similar to simple diffusion. does not require metabolic energy and therefore is passive. is more rapid than simple diffusion. is carrier-mediated and therefore exhibits stereospecificity, saturation, and competition.2. Example of facilitated diffusion Glucose transport

46、in muscle and adipose cells is “downhill,” is carrier-mediated, and is inhibited by sugars such as galactose; therefore, it is categorized as facilitated diffu- sion. In diabetes mellitus, glucose uptake by muscle and adipose cells is impaired because the carriers for facilitated diffusion of glucos

47、e require insulin.D. Primary active transport1. Characteristics of primary active transport occurs against an electrochemical gradient (“uphill”). requiresdirect input of metabolic energy intheformofadenosinetriphosphate(ATP) and therefore is active. is carrier-mediated and therefore exhibits stereo

48、specificity, saturation, and competition.2. Examples of primary active transporta. Na+,K+-ATPase (or Na+K+ pump) in cell membranes transports Na+ from intracellular to extracellular fluid and K+ from extracellular to intracellular fluid; it maintains low intracellular Na+ and high intracellular K+.4

49、Board Review Series: Physiology Both Na+ and K+ are transported against their electrochemical gradients. Energy is provided from the terminal phosphate bond of ATP. The usual stoichiometry is 3 Na+/2 K+. Specific inhibitors of Na+,K+-ATPase are the cardiac glycoside drugs ouabain anddigitalis.Ca2+-A

50、TPase (orpump) in the sarcoplasmic reticulum (SR) or cell membranes transports Ca2+ against an electrochemical gradient. Sarcoplasmic and endoplasmic reticulum Ca2+-ATPase is called SERCA.H+,K+-ATPase (orprotonpump) in gastric parietal cellstransports H+ intothe lumen of the stomach against its elec

51、trochemical gradient. It is inhibited by proton pump inhibitors, such as omeprazole.Ca2+b.c.E.Secondary active transport1.Characteristics of secondary active transportThe transport of two or more solutes is coupled.One ofthe solutes(usuallyNa+)istransported“downhill”andprovidesenergyfor the“uphill”

52、transport of the other solute(s).a.b.Metabolic energy is not provided directly, but indirectly from the Na+ gradient that is maintained across cell membranes. Thus, inhibition of Na+,K+-ATPase will decrease transport of Na+ out of the cell, decrease the transmembrane Na+ gradient, and even- tually i

53、nhibit secondary active transport.If the solutes move in the same direction across the cell membrane, it is called cotrans- port, or symport. Examples are Na+glucose cotransport in the small intestine and Na+K+2Cl cotrans- port in the renal thick ascending limb.If the solutes move in opposite direct

54、ions across the cell membranes, it is called counter- transport, exchange, or antiport. Examples are Na+Ca2+ exchange and Na+H+ exchange.c.d.e.Example of Na+glucose cotransport (Figure 1-1)a. The carrier for Na+glucose cotransport is located in the luminal membrane of intes- tinal mucosal and renal

55、proximal tubule cells.b. Glucose is transported “uphill”; Na+ is transported “downhill.”c. Energy is derived from the “downhill” movement of Na+. The inwardly directed Na+ gradient is maintained by the Na+K+ pump on the basolateral (blood side) mem- brane. Poisoning the Na+K+ pump decreases the tran

56、smembrane Na+ gradient and consequently inhibits Na+glucose cotransport.2.LumenIntestinal or proximal tubule cellBloodNa+K+Na+Na+Na+GlucoseNa+Secondary activePrimary activeFIGURE 1-1 Na+glucose cotransport (symport) in intestinal or proximal tubule epithelial cell. Chapter 1 Cell Physiology5Secondary activeNa+Ca2+Ca2+Ca2+Na+K+Na+Na+Primary activeFIGURE 1-2 Na+Ca+ countertransport (antiport).3. Example of Na+Ca2+ countertrans