A manual of physiology; for students of medicine

Preface

The present volume has been written at the desire on the part of the Publishers that a new elementary treatise on Physiology should be added to the series of admirable students' manuals which they had previously issued.

In carrying this desire into execution I have endeavored to avoid theories which have not borne the test of time, and such details of methods as are unnecessary for junior students. I do not give any history of how our knowledge has grown to its present stand-point ; nor do I mention the names of the authorities upon whose writings my statements depend. I have also omitted the mention of exceptional points, because I find that exceptions are more easily remembered than the main facts from which they differ ; and, since we must often be content with the retention of the one or the other, I have tried to insure that it shall be the more important.

While endeavoring to save the student from doubtful and erroneous doctrines, 1 have taken great care not to omit any important facts that are necessary to his acquirement of as clear an idea as possible of the principles of Physiology.

I have not hesitated to lay unwonted stress upon those points which many years' practical experience as a teacher and vm PREFACE.

an oxainiiier has sliowii inc arc difficult to grasp and are commonly misunderstood ; and 1 have treated such subjects as are useful in ihe practice of medicine or surgery, more fully than those which are essential only to abstract physiological knowledge.

As medical students are generally obliged to commence the study of Physiology without any anatomical knowledge, I believe it to be absolutely necessary that their first physiological book should contain some account of the structure and relationships of the organs, the functions of which they are about to study. I have therefore added a short account of the construction of the various })arts discussed in each chapter; it has, however, been found necessary to curtail this anatomical portion to a mere introductory sketch. Numerous illustrations, with full descriptions attached to each, are introduced to supplement the explanation given in the text.

So far as is consistent with an accurate treatment of the subject, I have avoided technical terms and scientific modes of expression. I know that in attempting to explain physiological truths in every-day language and in a plain common-sense way, I run the risk of appearing to lack the precision that such a subject demands ; but after mature consideration Lhave come to the conclusion that great scientific nicety and a scholastic style of expression have a deterrent effect upon the beginner's industry ; and I think it better that he should acquire the first principles of the science in homely language, than pick up technical odds and ends in learned terms, the meaning of which he does not comprehend.

As many words, strange to the first year's student, have to be used and must be learned, it has been thought advisable to

PREFACE. IX

add a short glossary, containing an explanation of the most ordinary physiological expressions.

Great difficulty is always found in fixing upon a starting point at which to begin the study of Physiology. To begin with the circulation of the blood, which is so essential for the life of every tissue, one should have some knowledge of nerve and muscle. To begin with nerves and muscles the mechanisms and the uses of the blood current should be understood ; and so on throughout the various systems, which are so interdependent that, for the thorough comprehension of any one, a knowledge of all is required.

I have, therefore, adopted the time-honored plan of commencing with the vegetative systems and following the course of the aliments to their destination and final application, as I believe that this arrangement is open to as few objections as any other known to me.

I wish here to express my most cordial thanks to many friends who have aided me with kind assistance and advice. I am deeply indebted to Mr. W. Tyrrell Brooks for the great help he afforded me by compiling the chapters on Development; and I feel I cannot sufficiently thank Mr. E. F. Herroun for his untiring and valuable assistance in the revision of the proof-sheets.

To Mr. G. Hanlon I am indebted for the careful and skilful manner in which he has executed the new woodcuts, most of which he had to copy from my rough drawings.

CHAPTER I. The Objects of Physiology

PAGE

Introductory Definitions, 17

Structural and Physical Properties of Organisms, . . . .20

Chemical Composition, 21

Vital Phenomena, 23

CHAPTER ir.

General View of the Structube of Animal Organisms.

Cells

. 25

Protoplasm, Nucleus. Cell-wall,

. 27

Cell-contents

. 29

Varieties of Cells,

. 30

Modifications of Original Cell-tissues, .

. 32

I. Epithelial Tissues,

. 35

II. Nerve Tissues,

. 39

III. Muscle or Contractile Tissues,

. 42

IV. Connective Tissues,

. 45

CHAPTER III. Chemical Basis op the Body

Elements in the Body 54

Classification of Ingredients found in llie Tissue.s, . . . .56

Plasmata, .56

Albuminous Bodies, .......... 59

Classification of Albumins, ......... 60

.\lbuniinoid8, 63

CONTENTS.

PACE

Products of Tissue Change, 05

Carbohydrates, GO

Fats '71

Inorganic Bodies, . . . . . . . . . . .71

The Mechanism of Digestion.

Mastication, ' 104

Deglutition, 100

Nervous Mechanism of Deglutition, Ill

Vomiting, . 115

Movements of the Intestines, 117

Defecation, 119

Nervous Mechanism of the Intestinal Motion, 121

CHAPTER VII. Mouth Digestion

Salivary and Mucous Glands 125

Characters of Mixed Saliva, 129

CONTEXTS. XUl

PAGE

Nervous Mechanism of Secretion of Saliva, 130

Changes in the Glaud-cells, 137

Functions of the Saliva, . . . . . . . ... 140

CHAPTER VIII. The Stomach Digestion

The Gastric Glands, .143

The Characters of Gastric Juice, 145

Mode of Secretion of Gastric Juice, ....... 147

Action of the Gastric Juice, . 149

CHAPTER IX. Pancreatic Juice

Structure of the Pancreas, 155

Characters and Mode of Secretion of Pancreatic Juice, . . . 156

Changes in the Gland-cells, 158

Action of Pancreatic Juice on Proteids, . . . . . . 160

Action on Fats, 161

Action on Starch, 162

CHAPTER X. Bile

Functions of the Liver, 163

Structure of the Liver, 164

Composition and Method of obtaining Bile, 169

Method of Secretion of Bile, 173

Functions of the Bile, 175

CHAPTER XL

Functions of the Intestinal Mucous Membrane.

Structure of the Small Intestines, Method of obtaining Intestinal Secretion, . Characters and Functions of the Intestinal Juice, Functions of the Large Intestine, Putrefactive Fermentations in the Intestine,

178 180 181 183

• 184

XIV

CONTENTS.

CHAPTER Xri.

Absorption

Interstitial Absorption, The Lymphatic System, Stnicture of Lymphatic Glands, Intestinal Absorption, .

Mechanism of Absorption, Materials Absorbed, Lymph and Chyle, Movement of the Lymph,

PAGE

CHAPTER XIII.

The Constitution of the Blood and the Blood-plasma.

General Characters of the Blood, 210

Amount of Blood in the Body, 211

Physical Construction of the Blood, Blood-plasma, . . . .213

Chemical Composition of Plasma, ....... 216

Preparation and Properties of Fibrin, . . . . . .218

CHAPTER XIV.

Blood-Corpuscles.

Proportion of Red to White. 220

White Blood-cells, 221

Origin of the Colorless Blood-cells, 223

The Red Corpuscles, Sizes and Shapes, 224

Action of Reagents on Red Corpuscles, 227

Method of counting Corpuscles, ; . 230

Chemistry of the Coloring Matter of the Blood, 231

Spectra of Haemoglobin, 234

Haematin, 235

Development of the Red Disks, 237

The Gases of the Blood, 239

CHAPTER XV.

Coagulation of the Blood.

Formation of the Blood-clot, Circumstances influencing Coagulation,

241 244

CONTENTS. XV

PAGE

The Cause of Coagulation, 245

Coagulation in the Vessels, 247

Formation of Fibrin, ...» 248

CHAPTER XVI.

The Heart.

Pulmonary and Systemic Circulations, 251

Method of the Circulation of the Blood, 252

The Heart, 256

Arrangement of Muscle Fibres, 256

Minute Structure of the Heart, 258

Action of the Valves, 260

Movements of the Heart, ....... . 262

Cycle of the Heart-beat, 263

The Heart's Impulse, 266

Heart-sounds, 269

Innervation of the Heart, 271

Local Centres, 272

Inhibitory Nerves, 276

Acceleration Nerves, ........ . 277

Afferent Cardiac Nerves, 278

CHAPTER XVII.

The Bloodvessels.

Structure of the Vessels, 279

The Capillaries, 281

Relative Capacity of tlie Vessels, ....... 283

Physical Forces of the Circulation, ....... 285

The Blood-pressure, .......... 287

Measurement of Blood-pressure, 291

Variations in the Blood-pressure, 295

Influence of Respiration on the Blood-pressure, ..... 297

The Arterial Pulse, 302

Methods of obtaining Pulse-tracings, 304

Variations in the Pulse, . . 307

Velocity of the Blood-current 308

Controlling Mechanisms of the Bloodvessels, 312

XVI CONTENTS.

CHAPTER XVIII.

The Mechanism of Respiration.

PAGE

Gas Interchange, . . . 318

Structure of the Lungs and Air-passages, 321

The Thorax 324

Thoracic Movements, . 326

Inspiratory Muscles, ....;..... 329

Expiration, 332

Function of the Pleura, ......... 334

Pressure Diflerences in tlie Air, ........ 336

The Volume of Air, 337

Nervous Mechanism of Respiration, 339

Modified Respiratory Movements, . 345

CHAPTER XIX.

The Chemistry of Respiration.

Composition of the Atmosphere, 347

Expired Air, 348

Changes the Blood undergoes in the Lungs, ..... 350

Gases in the Blood, 352

Internal Respiration, 355

Respiration of Poisonous Gases, 356

Ventilation, 357

CHAPTER XX.

Blood-Elaborating Glands.

Ductless Glands, 361

Supra-renal Capsule, 362

Thyroid Body, 363

Thymus, 364

Spleen, 364

Functions of the Spleen, 365

Glycogenic Function of tlie Liver, ....... 369

Glycogen 372

CONTENTS. XVU

CHAPTER XXI.

Secretions.

PAGE

Lachrymal Glands, 374

Mucous Glands, 375

Sebaceous Glands, .......... 377

Mammary Glands, 378

Composition of Milk, 380

Sudoriferous Glands, 383

Cutaneous Desquamation, ..... .... 385

CHAPTER XXII.

Urinary Excretion.

Structure of the Kidneys, 388

Bloodvessels of the Kidneys, 389

Urine, 391

Method of Secretion of tiie Urine, ....... 393

Chemical Composition of the Urine, 397

Urea, 398

Uric Acid, 399

Kreatinin, Xanthin, Hippuric Acid, etc., ...... 400

Coloring Matters and Inorganic Salts, 401

Abnormal Constituents, 403

Urinary Calculi, 404

Source of Urea, etc., 405

Nervous Mechanism of the Urinary Secretion, 407

Outflow of Urine, 408

Nervous Mechanism of Micturition, 411

CHAPTER XXIII.

Nutrition.

Tissue Changes during Starvation, 414

Food Requirements, 417

Ultimate Uses of Food-stuffs, 423

CHAPTER XXIV.

Animal, Heat.

Warm- and Cold-blooded Animals, 425

Variations in the Body Temperature, * 426

XV 111 CONTENTS.

PAGE

Mode of Production of Animal Heat, 428

Income and Expenditure of Heat, 429

Maintenance of Uniform Temperature, 432

CHAPTER XXV.

Contractile Tissues.

Histology of Muscle, 439

Properties of Muscle in the Passive State, 442

Electric Phenomena of Muscle, ........ 445

Active State of Muscle, 448

Muscle Stimuli, • . . . . 449

Changes occurring in Muscle on its entering the Active State, . . 452

Muscle Contraction, 457

Graphic Method of recording Contraction, 458

Tetanus, Fatigue, etc., 465

Kigor Mortis, '. . 471

Unstriated Muscle, 473

CHAPTER XXVI.

The Application of Skeletal Muscles.

General Arrangements, 474

Joints, 475

Standing, 478

Walking and Running, 481

CHAPTER XXVII.

Voice and Speech.

Mechanism of Vocalization, . 486

Properties of the Human Voice, 488

Nervous Mechanism of Voice, 491

Speech, 491

CHAPTER XXVIII.

General Physiology of the Neryous System.

Functional Classification, 496

Chemistry and Electric Properties of Nerves, ..... 498

COXiENTS. XIX

PAGE

The Active State of Nerve-fibres, 499

Nerve Stimuli, 499

Velocity of Nerve-impulse, 502

The Electric Changes in Nerves, 504

Irritability of Nerve-fibres, 506

Law of Contraction, 509

Nerve Corpuscles and Terminals, 511

Functions of the Nerve Cells, 513

CHAPTER XXIX.

Special Physiology op Nerves.

Spinal Nerves, 517

The Cranial Nerves, 518

The Trochlear Nerve, 521

Portio Dura, etc., 522

Eflferent and Afferent Fibres, 524

Ganglia of the Fifth Nerve, .526

The Glosso-pharyngeal Nerve, 527

The Vagus Nerve, 528

The Hypoglossal Nerve 531

CHAPTER XXX.

Special Senses.

Skin Sensations, 535

Nerve Endings, 536

Sense of Locality, 539

Sense of Pressure, . . '. 542

Temperature Sense, 543

General Sensations, 545

CHAPTER XXXI.

Taste and Smell.

Sense of Taste, 548

Sense of Smell 551

CONTENTS.

CHAPTER XXXII.

Vision.

The Construction of the Eyebiill,

Dioptric Media of tiie Eyeball,

Structure of the Lens, .

The Dioptrics of the Eye, .

Accoinnioilatioii, .

Defects of Accommodation, .

Defects of Dioptric Apparatus,

The Iris, ....

The Ophthalmoscope, .

Visual Impressions,

The Fnnction of the Ketina,

Color Perceptions,

Mental Operations in Vision,

Movements of the Eyeballs,

IJinocular vision, .

PAGE

CHAPTER XXXIII.

Hearing.

Sound, 594

Conduction of Sound vibrations through the Outer Ear, . . . 598

Conduction through the Tympanum, 601

Conduction through the Labyrinth, 603

Stimulation of the Auditory Nerve, . 607

CHAPTER XXXIV.

Central Nervous Organs.

Nerve Cells, 611

The Spinal Cord as a Conductor, 614

The Spinal Cord as a Collection of Nerve Centres, .... 616

Special Reflex Centres, 625

Automatism, . 626

CHAPTER XXXV.

The Medulla Oblongata.

The Medulla Oblongata as a Conductor, The Respiratory Centre,

628 630

CONTENTS.

XXI

The Yaso-motor Centre, The Cardiac Centre,

PAGE

632 634

CHAPTER XXXVI.

The Brain.

The Mesencephalon and Cerebellum, 637

Crura Cerebri, 640

Basal Ganglia, 641

Cerebral Hemispheres, ......... 644

Localization of the Cerebral Functions, 646

CHAPTER XXXVII.

Eeproduction.

Origin of Male and Female Generative Elements, .... 650

Menstruation and Ovulation, 653

Changes in the Ovum subsequent to Impregnation, .... 656

Formation of the Membranes, 660

The Placenta, 666

CHAPTER XXXVIII.

Development.

Development of the Vertebral Axis, 671

Development of the Central Nervous System,

The Alimentary Canal and its Appendages,

The Genito-urinary Apparatus, .

The Blood-vascular System, . . .

Development of the Eye, ....

Development of the Ear, ....

Development of the Skull and Face, .

Index,

COMPARISON OF JVIEASURES.

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