25,99 €
Mehr erfahren.
- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
- Veröffentlichungsjahr: 2023
The knee-bone's connected to the...what was it again? From complicated Latin names to what can seem like a million-and-one things to memorize, no one's saying anatomy and physiology is easy. But, with a little help from your friends at Dummies, it doesn't have to be impossible! Anatomy & Physiology All-in-One For Dummies is your go-to guide for developing a deep understanding of the parts of the human body and how it works. You'll learn the body's structures and discover how they function with expert help from the book's easy-to-use teaching features. You can even go online to access interactive chapter quizzes to help you absorb the material. With this book, you'll: * Get a grip on key concepts and scientific terminology used to describe the human body * Discover fun physiology facts you can apply to everyday life both inside and outside the classroom * Learn how the body's different systems interact with one another So, if you're looking to ace that next test, improve your overall grade, reduce test anxiety, or just increase your confidence in the subject, grab a copy of Anatomy & Physiology All-in-One For Dummies. It's your one-stop, comprehensive resource for all things A&P!
Sie lesen das E-Book in den Legimi-Apps auf:
Seitenzahl: 757
Ähnliche
Anatomy & Physiology All-in-One For Dummies®
Published by: John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030-5774, www.wiley.com
Copyright © 2023 by John Wiley & Sons, Inc., Hoboken, New Jersey
Published simultaneously in Canada
No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without the prior written permission of the Publisher. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) 748-6011, fax (201) 748-6008, or online at http://www.wiley.com/go/permissions.
Trademarks: Wiley, For Dummies, the Dummies Man logo, Dummies.com, Making Everything Easier, and related trade dress are trademarks or registered trademarks of John Wiley & Sons, Inc. and may not be used without written permission. All other trademarks are the property of their respective owners. John Wiley & Sons, Inc. is not associated with any product or vendor mentioned in this book.
LIMIT OF LIABILITY/DISCLAIMER OF WARRANTY: WHILE THE PUBLISHER AND AUTHORS HAVE USED THEIR BEST EFFORTS IN PREPARING THIS WORK, THEY MAKE NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY OR COMPLETENESS OF THE CONTENTS OF THIS WORK AND SPECIFICALLY DISCLAIM ALL WARRANTIES, INCLUDING WITHOUT LIMITATION ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. NO WARRANTY MAY BE CREATED OR EXTENDED BY SALES REPRESENTATIVES, WRITTEN SALES MATERIALS OR PROMOTIONAL STATEMENTS FOR THIS WORK. THE FACT THAT AN ORGANIZATION, WEBSITE, OR PRODUCT IS REFERRED TO IN THIS WORK AS A CITATION AND/OR POTENTIAL SOURCE OF FURTHER INFORMATION DOES NOT MEAN THAT THE PUBLISHER AND AUTHORS ENDORSE THE INFORMATION OR SERVICES THE ORGANIZATION, WEBSITE, OR PRODUCT MAY PROVIDE OR RECOMMENDATIONS IT MAY MAKE. THIS WORK IS SOLD WITH THE UNDERSTANDING THAT THE PUBLISHER IS NOT ENGAGED IN RENDERING PROFESSIONAL SERVICES. THE ADVICE AND STRATEGIES CONTAINED HEREIN MAY NOT BE SUITABLE FOR YOUR SITUATION. YOU SHOULD CONSULT WITH A SPECIALIST WHERE APPROPRIATE. FURTHER, READERS SHOULD BE AWARE THAT WEBSITES LISTED IN THIS WORK MAY HAVE CHANGED OR DISAPPEARED BETWEEN WHEN THIS WORK WAS WRITTEN AND WHEN IT IS READ. NEITHER THE PUBLISHER NOR AUTHORS SHALL BE LIABLE FOR ANY LOSS OF PROFIT OR ANY OTHER COMMERCIAL DAMAGES, INCLUDING BUT NOT LIMITED TO SPECIAL, INCIDENTAL, CONSEQUENTIAL, OR OTHER DAMAGES.
For general information on our other products and services, please contact our Customer Care Department within the U.S. at 877-762-2974, outside the U.S. at 317-572-3993, or fax 317-572-4002. For technical support, please visit https://hub.wiley.com/community/support/dummies.
Wiley publishes in a variety of print and electronic formats and by print-on-demand. Some material included with standard print versions of this book may not be included in e-books or in print-on-demand. If this book refers to media such as a CD or DVD that is not included in the version you purchased, you may download this material at http://booksupport.wiley.com. For more information about Wiley products, visit www.wiley.com.
Library of Congress Control Number: 2023930263
ISBN 978-1-394-15365-7; ISBN 978-1-394-15366-4 (ebk); ISBN 978-1-394-15367-1 (ebk)
Anatomy and Physiology All-in-One For Dummies®
To view this book's Cheat Sheet, simply go to www.dummies.com and search for “Anatomy and Physiology All-in-One For Dummies Cheat Sheet” in the Search box.
Table of Contents
Cover
Title Page
Copyright
Introduction
About This Book
Foolish Assumptions
Icons Used in This Book
Beyond the Book
Where to Go from Here
Unit 1: Locating Physiology on the Web of Knowledge
Chapter 1: Learning a New Language: How to Speak Fluent A&P
A Word about Jargon
Looking at the Body from the Proper Perspective
Getting Organized
Whaddya Know? Chapter 1 Quiz
Answers to Chapter 1 Quiz
Chapter 2: Better Living through Chemistry
What’s the Matter?
Keep Your Ion the Prize
Building Blocks That Build You
Metabolism: It’s More Than Just Food
Charging Your Batteries
Practice Questions Answers and Explanations
Whaddya Know? Chapter 2 Quiz
Answers to Chapter 2 Quiz
Chapter 3: The Secret Life of Cells
Keeping Same Things the Same: Homeostasis
Division of Labor
Controlling the Ins and Outs
Divide and Conquer
Practice Questions Answers and Explanations
Whaddya Know? Chapter 3 Quiz
Answers to Chapter 3 Quiz
Chapter 4: Joining Forces: Cells Organize into Tissues
Covering Up: Epithelial Tissues
Making a Connection: Connective Tissues
Flexing It: Muscle Tissues
Getting the Signal Across: Nervous Tissue
Whaddya Know? Chapter 4 Quiz
Answers to Chapter 4 Quiz
Unit 2: Weaving It All Together: The Structural Layers
Chapter 5: It’s Just Skin Deep: The Integumentary System
Meet & Greet and Love the Skin You’re In
Digging Deep into Dermatology
No Skin Is Complete without Accessories
Your Sensational Skin
Practice Questions Answers and Explanations
Whaddya Know? Chapter 5 Quiz
Answers to Chapter 5 Quiz
Chapter 6: More than a Scaffold to Build On: The Skeletal System
Meet & Greet Your Body’s Foundation
Boning Up on Bone Structures
Turning Bones into Bone
The Axial Skeleton
The Appendicular Skeleton
Artful Articulations
Practice Questions Answers and Explanations
Whaddya Know? Chapter 6 Quiz
Answers to Chapter 6 Quiz
Chapter 7: Getting in Gear: The Muscles
Meet & Greet Your Mighty Muscles
Structure Matches Function
The Electric Slide
Push, Pull, & Hold
What’s in a Name?
Practice Questions Answers and Explanations
Whaddya Know? Chapter 7 Quiz
Answers to Chapter 7 Quiz
Unit 3: Talking to Yourself
Chapter 8: Your Electric Personality
Meet & Greet the Far-Reaching Nervous System
Integrating the Input with the Output
Feeling Impulsive?
Minding the Central Nervous System
Taking the Side Streets: The Peripheral Nervous System
Sensory Overload
Practice Questions Answers and Explanations
Whaddya Know? Chapter 8 Quiz
Answers to Chapter 8 Quiz
Chapter 9: Raging Hormones: The Endocrine System
Meet & Greet Your Body’s Chemical Messengers
Honing In on Hormones
The Ringmasters
The Cast of Characters
Practice Questions Answers and Explanations
Whaddya Know? Chapter 9 Quiz
Answers to Chapter 9 Quiz
Unit 4: Traveling the World
Chapter 10: The River(s) of Life
Blood Is Thicker than Water
The In-Between
Of Sirens and Lymphs
Whaddya Know? Chapter 10 Quiz
Answers to Chapter 10 Quiz
Chapter 11: Spreading the Love: The Cardiovascular System
Meet & Greet Your Pumping Station
Home Is Where the Heart Is
Your Heart Song
Moving to the Beat of Your Own Drum
Practice Questions Answers and Explanations
Whaddya Know? Chapter 11 Quiz
Answers to Chapter 11 Quiz
Chapter 12: Underground Defenses: The Lymphatic System
Meet & Greet Your Body’s Customs and Border Control
Immunity: A Three-Act Play
Act 1: Innate Immunity
Act 2: Adaptive Immunity
Act 3: Becoming Immune
Practice Questions Answers and Explanations
Whaddya Know? Chapter 12 Quiz
Answers to Chapter 12 Quiz
Unit 5: Supply and Demand
Chapter 13: Oxygenating the Machine: The Respiratory System
Meet & Greet the Old Windbags
A Breath of Fresh Air
Breathe In the Good, Breathe Out the Bad
All in One Breath
Practice Questions Answers and Explanations
Whaddya Know? Chapter 13 Quiz
Answers to Chapter 13 Quiz
Chapter 14: Fueling the Fire: The Digestive System
Meet & Greet the Alimentary School
Nothing to Spit At
The Stomach: More Than a Vat of Acid
Breaking Down Digestive Enzymes
Double Duty: The Small Intestine and the Liver
One Last Look Before Leaving
Practice Questions Answers and Explanations
Whaddya Know? Chapter 14 Quiz
Answers to Chapter 14 Quiz
Chapter 15: Cleaning Up Your Act: The Urinary System
Meet & Greet the Body’s Recycling and Waste Management System
Focus on Filtration
The Yellow River
The Homeostasis Machines
Practice Questions Answers and Explanations
Whaddya Know? Chapter 15 Quiz
Answers to Chapter 15 Quiz
Unit 6: Making a Mini-Me: Behind the Scenes
Chapter 16: Why Ask Y? Gamete Production
Producing Gametes
Meet & Greet the Male Reproductive System
Meet & Greet the Female Reproductive System
Practice Questions Answers and Explanations
Whaddya Know? Chapter 16 Quiz
Answers to Chapter 16 Quiz
Chapter 17: Baking the Bundle of Joy
Fertilization: A Battle for the Ages!
And So It Begins
Finishing Out the Trimesters
The Fun Part: Labor and Delivery
Practice Questions Answers and Explanations
Whaddya Know? Chapter 17 Quiz
Answers to Chapter 17 Quiz
Chapter 18: From Cradle to Grave
Programming Development
Human Life Span
Whaddya Know? Chapter 18 Quiz
Answers to Chapter 18 Quiz
Index
About the Author
Supplemental Images
Connect with Dummies
End User License Agreement
List of Tables
Chapter 1
Table 1-1 Technical Anatomical Word Fragments
Table 1-2 The Body’s Regions
Chapter 6
Table 6-1 Characteristics of Bone Types
Table 6-2 Regions of the Vertebral Column
Chapter 7
Table 7-1 Structures of a Sarcomere
Table 7-2 Characteristics in Muscle Names
Chapter 8
Table 8-1 Glial Cells
Table 8-2 Functions of Lobes within Cerebral Hemispheres
Table 8-3 Sensory Receptor Types
Chapter 9
Table 9-1 Important Hormones: Sources and Primary Functions
Chapter 12
Table 12-1 Cells of the Immune System
Chapter 14
Table 14-1 Pancreatic Enzymes
Chapter 16
Table 16-1 Reproduction Terms to Know
List of Illustrations
Chapter 1
FIGURE 1-1: The standard anatomical position.
FIGURE 1-2: Planes of the body: frontal, sagittal, and transverse.
FIGURE 1-3: The body’s regions: Anterior view.
FIGURE 1-4: The body’s regions: Posterior view.
FIGURE 1-5: Body cavities.
FIGURE 1-6: Abdominal regions.
Chapter 2
FIGURE 2-1: The hydrogen bonding of water molecules.
FIGURE 2-2: Mono- and disaccharides.
FIGURE 2-3: DNA is made up of thousands of nucleotides.
FIGURE 2-4: The structures of ADP and ATP.
FIGURE 2-5: The ATP/ADP cycle.
Chapter 3
FIGURE 3-1: A cutaway view of an animal cell and its organelles.
FIGURE 3-2: The cell membrane.
FIGURE 3-3: Cell structures and changes that make up the stages of the cell cyc...
Chapter 4
FIGURE 4-1: Areolar tissue (a) and dense regular connective tissue (b).
FIGURE 4-2: Muscle tissues: Smooth, cardiac, and skeletal.
FIGURE 4-3: Identify this tissue.
FIGURE 4-4: Identify the tissue type.
FIGURE 4-5: Epithelial tissues.
FIGURE 4-6: Identify this tissue type.
Chapter 5
FIGURE 5-1: The epidermis.
FIGURE 5-2: Layers of epidermis.
FIGURE 5-3: A nail bed.
Chapter 6
FIGURE 6-1: Long bone structure.
FIGURE 6-2: The long bone.
FIGURE 6-3: Compact osseous tissue structure.
FIGURE 6-4: Bone tissue cross section.
FIGURE 6-5: The spinal column, side view.
FIGURE 6-6: A lateral view of the skull.
FIGURE 6-7: Sinus view of the skull.
FIGURE 6-8: Vertebral column.
FIGURE 6-9: The bones of the pelvis.
FIGURE 6-10: The bones of the upper limb and hand.
FIGURE 6-11: The bones of the lower limb and foot.
FIGURE 6-12: A synovial joint.
Chapter 7
FIGURE 7-1: Muscle tissue types.
FIGURE 7-2: Anatomy of a skeletal muscle fiber.
FIGURE 7-3: Anatomy of a myofibril.
FIGURE 7-4: Sarcomere structure and shortening: (a) sarcomere before contractio...
FIGURE 7-5: Sarcomere.
FIGURE 7-6: Organizational structure of a muscle.
FIGURE 7-7: The muscles of the head and neck.
FIGURE 7-8: Anterior muscles of the chest and abdomen.
FIGURE 7-9: Posterior view of the torso and arm muscles.
FIGURE 7-10: Anterior muscles of the lower limb.
FIGURE 7-11: Posterior muscles of the lower limb.
FIGURE 7-12: The neuromuscular junction.
Chapter 8
FIGURE 8-1: The motor neuron on the left and the sensory neuron on the right sh...
FIGURE 8-2: Graphic organizer showing the relationship between nervous system d...
FIGURE 8-3: Impulse transmission: (a) stimulus of dendrite, (b) generation and ...
FIGURE 8-4: Synaptic transmission.
FIGURE 8-5: Cross section of the spinal cord.
FIGURE 8-6: The ventricles of the brain.
FIGURE 8-7: Sagittal view of the brain.
FIGURE 8-8: The sympathetic and parasympathetic nervous systems.
FIGURE 8-9: The internal structures of the eye.
FIGURE 8-10: The anatomy of the ear.
FIGURE 8-11: A reflex arc responding to pain.
FIGURE 8-12: Sagittal view of the brain.
FIGURE 8-13: Basic brain anatomy.
Chapter 9
FIGURE 9-1: The working relationship of the hypothalamus and the pituitary glan...
FIGURE 9-2: The endocrine system.
Chapter 10
FIGURE 10-1: Capillary exchange.
Chapter 11
FIGURE 11-1: The cardiovascular system is a closed double loop.
FIGURE 11-2: A typical healthy heart.
FIGURE 11-3: The heart and major vessels.
FIGURE 11-4: The heart valves.
FIGURE 11-5: The conduction system of the heart.
FIGURE 11-6: A typical EKG.
FIGURE 11-7: The anatomy of an artery.
FIGURE 11-8: The anatomy of an artery.
Chapter 12
FIGURE 12-1: Lymphatic flow.
FIGURE 12-2: A lymph node.
FIGURE 12-3: Cell-mediated immunity.
FIGURE 12-4: Humoral immunity and antibody actions.
Chapter 13
FIGURE 13-1: Front (a) and lateral (b) views of the larynx.
FIGURE 13-2: The respiratory tract.
FIGURE 13-3: The inspiration (inhalation) and expiration (exhalation) process.
FIGURE 13-4: Respiratory gases are exchanged by diffusion across alveolar and c...
FIGURE 13-5: The alveoli.
Chapter 14
FIGURE 14-1: The composition of a tooth.
FIGURE 14-2: Structures of the mouth and throat.
FIGURE 14-3: A closer look at the liver.
FIGURE 14-4: The features of the stomach.
FIGURE 14-5: The organs and glands of the digestive system.
Chapter 15
FIGURE 15-1: Glomerular filtration.
FIGURE 15-2: Nephron action.
FIGURE 15-3: Nephron structures.
Chapter 16
FIGURE 16-1: The process of meiosis.
FIGURE 16-2: The human ovum.
FIGURE 16-3: The human sperm.
FIGURE 16-4: Testis.
FIGURE 16-5: The male reproductive system.
FIGURE 16-6: The human breast.
FIGURE 16-7: An ovary.
FIGURE 16-8: The female reproductive organs.
Chapter 17
FIGURE 17-1: Early prenatal development.
FIGURE 17-2: A fetus late in the third trimester.
FIGURE 17-3: Effacement of the cervix in early labor.
FIGURE 17-4: An overview of delivery.
Guide
Cover
Table of Contents
Title Page
Copyright
Begin Reading
Index
About the Author
Author’s Acknowledgments
Dedication
Pages
i
iii
iv
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
257
258
259
260
261
262
263
264
265
266
267
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
Introduction
Whether your aim is to become a physical therapist or a pharmacist, a doctor or an acupuncturist, a nutritionist or a personal trainer, a registered nurse or a paramedic, a parent or simply a healthy human being, your efforts have to be based on a good understanding of anatomy and physiology. But knowing that the knee bone connects to the thigh bone (or does it?) is just the tip of the iceberg.
The human body is a miraculous biological machine capable of growing, interacting with the world, and even reproducing despite numerous environmental odds stacked against it. Understanding how the body’s interlaced systems accomplish these feats requires a close look at everything from chemistry to structural mechanics.
Early anatomists relied on dissections to study the human body, which is why the Greek word anatomia means “to cut up or dissect.” Anatomical references have been found in Egypt dating back to 1600 BC, but it was the Greeks — Hippocrates in particular — who first dissected bodies for medical study around 420 BC. That’s why more than two millennia later, we still use words based on Greek and Latin roots to identify anatomical structures.
That’s also part of the reason why studying anatomy and physiology feels like learning a foreign language. Truth be told, you are working with a foreign language, but it’s the language of you and the one body you’re ever going to have.
About This Book
Anatomy and Physiology All-In-One For Dummies, 1st Edition, combines the idea of a simplified textbook with the practice opportunities of a workbook. It isn’t meant to replace a proper anatomy and physiology (A&P) textbook, and it’s certainly not meant to replace going to an actual class. It’s designed to be a supplement to your ongoing education and a study aid for prepping for exams. Sometimes, a slightly different presentation of a fact or of the relationship between facts can lead to a small “Aha!” moment; then technical details in your more comprehensive resources become easier to master. Consider reading the relevant chapter before class. That way, when your instructor covers the content, it’ll be more likely to stick.
Your coursework might cover things in a different order from the one I’ve chosen for this book. As an instructor, I’ve had years of trial and error in the order in which I teach topics. I’ve found the flow of this book to be the most successful for my students, and it does differ from the traditional order, particularly when you reach Unit 4, “Traveling the World,” which covers the fluids that circulate in your body. I welcome you to take full advantage of the table of contents and the index to find the material as it’s addressed in your class.
Whatever you do, don’t feel obligated to go through this book in the order I’ve chosen. But please do answer the practice questions and check the answers as you go. They are placed strategically, and in addition to providing the correct answers, I clarify why the right answer is the right answer and why the other answers are incorrect.
The goals of this book are to be informal but not unscientific, brief but not sketchy, and information-rich but accessible to readers at many levels. I’ve tried to present a light but serious survey of human anatomy and physiology that you can enjoy merely for the love of learning.
Foolish Assumptions
In writing this book, I had to make some assumptions about you, the reader — the most important of which is that you’re not actually a dummy! If any of the following applies, this book is for you:
Formal student:
You’re enrolled in an intro A&P course for credit or in a similar course tied to a particular certification or credential. You need to pass an exam or otherwise demonstrate understanding and retention of terminology, identification, and the processes of human anatomy and physiology.
Informal student:
You’re not enrolled in a course, but you’re interested in gaining some background knowledge or are reviewing content on human anatomy and physiology because it’s important to you for personal or professional reasons.
Casual reader:
High five to you for maintaining your love of learning. Your teachers would be so proud! Here you are with a book on your hands and a little time to spend reading it … and it’s all about you! I sincerely hope that you enjoy this book.
Because this book is an all-in-one text, I had to limit the exposition of the topics so that I could include lots of practice questions to keep you guessing. (Believe me, I could go on forever about this A&P stuff!) The final assumption I made is that if you’ve picked up this book to help you perform well in a course, you have access to a formal textbook. Particularly with the labeling of anatomical structures, I cover the main players, but you’ll likely be asked to identify more or to recognize more details about them.
Icons Used in This Book
Throughout this book, you’ll find symbols in the margins that highlight critical ideas and information. Here’s what they mean.
The Tip icon gives you juicy tidbits about how best to remember tricky terms or concepts. It also highlights helpful strategies for memory and understanding.
The Remember icon highlights key material that you should pay extra attention to so you can keep everything straight. It’s often included to cue you to make a connection with content on other body systems.
This icon — otherwise known as the Warning icon — points out areas and topics where common pitfalls can lead you astray.
The Technical Stuff icon flags extra information that takes your understanding of anatomy or physiology to a slightly deeper level, but the text isn’t essential for understanding the organ system under discussion.
This icon draws your attention to the review questions included in particular places to check your understanding. Answers are included before the end of chapter quiz. You should complete all the questions as best you can, from memory (don’t go back and look up the answers); then check and correct your answers after you complete the section. It’s also important that you give yourself a brain break before continuing to the next section.
Beyond the Book
Within this book, you may note that some web addresses break across two lines of text. If you’re reading this book in print and want to visit one of these web pages, simply key in the web address exactly as it’s noted in the text, pretending that the line break doesn’t exist. If you’re reading this book as an e-book, you’ve got it easy: Just click the web address to be taken directly to the web page.
In addition to the material in the print or e-book you’re reading right now, this product comes with some access-anywhere goodies on the web. Although it’s important to study each anatomical system in detail, it’s also helpful to know how to decipher unfamiliar anatomical terms the first time you see them. Check out the free Cheat Sheet by going to www.dummies.com and typing “Anatomy and Physiology All in One Cheat Sheet” in the search box.
You also get access to an online database of questions with even more practice for you. This database contains an interactive quiz for each chapter, allowing you to hone your new knowledge even more!
To gain access to the database, all you have to do is register. Follow these simple steps:
Register your book at
www.dummies.com/go/getaccess
to get your personal identification number (PIN).
Choose your product from the drop-down menu on that page.
Follow the prompts to validate your product.
Check your email for a confirmation message that includes your PIN and instructions for logging in.
If you don’t receive this email within two hours, please check your spam folder before contacting Wiley at https://support.wiley.com or by phone at (877) 762-2974.
Now you’re ready to go! You can come back to the practice material as often as you want. Simply log on with the username and password you created during your initial login; you don’t need to enter the access code a second time. Your registration is good for one year from the day you activate your PIN.
Where to Go from Here
If you purchased this book and are already partway through an A&P class, check the table of contents, and zoom ahead to whichever segment your instructor is covering. When you have a few spare minutes, review the chapters that address topics your class has already covered— an excellent way to prep for a midterm or final exam.
If you haven’t yet started a class, you have the freedom to start wherever you like (although I strongly recommend that you begin with Chapter 1) and then proceed onward and upward through the glorious machine that is the human body!
When you’ve finished, find a nice home on your bookshelf for this book. The unique, hand-drawn color plates alone make it worth the space it takes up. The book will be right there for you when you need a quick refresher, and it’ll be a great reference after a doctor’s appointment or the next time you wonder what the heck they’re talking about in a drug commercial.
Unit 1
Locating Physiology on the Web of Knowledge
In This Unit …
Chapter 1: Learning a New Language: How to Speak Fluent A&P
A Word about Jargon
Looking at the Body from the Proper Perspective
Getting Organized
Whaddya Know? Chapter 1 Quiz
Answers to Chapter 1 Quiz
Chapter 2: Better Living through Chemistry
What’s the Matter?
Keep Your Ion the Prize
Building Blocks That Build You
Metabolism: It’s More Than Just Food
Charging Your Batteries
Practice Questions Answers and Explanations
Whaddya Know? Chapter 2 Quiz
Answers to Chapter 2 Quiz
Chapter 3: The Secret Life of Cells
Keeping Same Things the Same: Homeostasis
Division of Labor
Controlling the Ins and Outs
Divide and Conquer
Practice Questions Answers and Explanations
Whaddya Know? Chapter 3 Quiz
Answers to Chapter 3 Quiz
Chapter 4: Joining Forces: Cells Organize into Tissues
Covering Up: Epithelial Tissues
Making a Connection: Connective Tissues
Flexing It: Muscle Tissues
Getting the Signal Across: Nervous Tissue
Whaddya Know? Chapter 4 Quiz
Answers to Chapter 4 Quiz
Chapter 1
Learning a New Language: How to Speak Fluent A&P
IN THIS CHAPTER
Learning to speak the language
Orienting yourself to the body
Exploring the body’s regions
Human anatomy is the study of our bodies’ structures; physiology is how they work. It makes sense, then, to learn the two in tandem. But before we can dive into the body systems and their intricate structures, you must learn to speak the language of the science.
A Word about Jargon
Why does science have so many funny words? Why can’t scientists just say what they mean, in plain English? Good question! The answer is a great place to start this chapter.
Scientists need to be able to communicate with others in their field, just like in any other career. They develop vocabularies of technical terminology and other forms of jargon so they can better communicate with colleagues. It’s important that both the scientist sending the information and the one receiving it use the same words to refer to the same phenomenon. They say what they mean (most of them, most of the time, to the best of their ability), but what they mean can’t be said in the English language that people use to talk about routine daily matters. As a result, we get jargon. And while it seems like an unnecessary obstacle on your course of learning something new, jargon is a good and needed thing.
Consider this. We’re sitting on a porch, enjoying a cool evening, and I say to you, “Hey! You got any tea?” You would likely offer whatever variety of hot tea you have (or kindly say that you don’t have any). Nothing too confusing there, right? If I were to ask my son (or any teenager, really) the same question, I wouldn’t be getting a refreshing beverage; I’d be getting the latest gossip. You know what I meant because the word tea means the same thing to us. But to my son, it’s like jargon.
To understand anatomy and physiology, you must know and use the same terminology as those in the field. The jargon can be overwhelming at first, but understanding the reason for it and taking the time to learn it before diving into the complicated content will make your learning experience less painful.
A great way to start is to take a moment to look at just how these complicated terms are created. The words sound foreign to us because they’re derived from Greek and Latin. Unlike other languages, those haven’t changed in centuries. Mono has always meant one, but I don’t even know what cool means anymore (except that my son says I’m not it!). In science, anatomy included, things are named by putting the relevant word roots together. Let’s look at the word dermatitis. The root derm- means skin, and -itis means inflammation. Put them together, and you get skin inflammation, commonly referred to as a rash. Table 1-1 gets you going with a list of commonly used word roots in anatomy and physiology, matched up with the body system in which you’ll likely encounter them.
Every time you come across an anatomical or physiological term that’s new to you, see whether you recognize any parts of it. Using this knowledge, go as far as you can in guessing the meaning of the whole term. After studying Table 1-1 and the other vocabulary lists in this chapter, you should be able to make some pretty good guesses!
Table 1-1 Technical Anatomical Word Fragments
Body System
Root or Word Fragment
Meaning
Skeletal
os-, oste-, arth-
bone, joint
Muscular
myo-, sarco-
muscle, striated muscle
Integument
derm-
skin
Nervous
neur-
nerve
Endocrine
aden-, estr-
gland, steroid
Cardiovascular
card-, angi-, hema-, vaso-
heart (muscle), vessel, blood vessels
Respiratory
pulmon-, bronch-
lung, windpipe
Digestive
gastr-, enter-, dent-, hepat-
stomach, intestine, teeth, liver
Urinary
ren-, neph-, ur-
kidney, urinary
Lymphatic
lymph-, leuk-, -itis
lymph, white, inflammation
Reproductive
andr-, uter-
male, uterine
Looking at the Body from the Proper Perspective
Remember that story about your sister’s friend’s boyfriend’s uncle who went in to have a foot amputated, only to awaken from surgery to find that the surgeon removed the wrong one? This story highlights the need for a consistent perspective to go with the jargon. Terms that indicate direction make no sense if you’re looking at the body the wrong way. You likely know your right from your left, but ignoring perspective can get you all mixed up. This section shows you the anatomical position, planes, regions, and cavities, as well as the main membranes that line the body and divide it into major sections.
Getting in position
Stop reading for a minute and do the following: Stand up straight. Look forward. Let your arms hang down at your sides and turn your palms so they’re facing forward. You are now in anatomical position (see Figure 1-1). Any time the position of one structure is compared with another, the relationship comes from the body in this position.
Illustration by Kathryn Born, MA
FIGURE 1-1: The standard anatomical position.
Unless you’re told otherwise, any reference to location (diagram or description) assumes this position. Using anatomical position as the standard removes confusion.
We also use directional terms to describe the location of structures. It helps to learn them as their opposing pairs to minimize confusion. The most commonly used terms are
Anterior/posterior:
in front of/behind
Ventral/dorsal:
toward the stomach/back (in humans, these mean the same as anterior/posterior)
Superior/inferior:
above/below
Medial/lateral:
closer to/farther from the midline (also used with rotation)
Superficial/deep:
closer to/farther from the body surface
Proximal/distal:
closer to/farther from the attachment point (used for appendages)
Right and left are also used quite often, but be careful! They refer to the patient’s right and left, not yours.
Dividing the anatomy
Because we can see only the external surface of the body, sections (cuts, in other words) must be made for us to see what’s inside. It’s important to take note of what type of section was made to provide the view you see in a picture or diagram. As illustrated in Figure 1-2, There are three planes (directions) in which these can be made:
Frontal:
Divides the body or organ into anterior and posterior portions. Think front and back. This plane is also referred to as
coronal.
Sagittal:
Divides the body or organ lengthwise into right and left sections. If the vertical plane runs exactly down the middle of the body, it’s referred to as the
midsagittal plane.
Transverse:
Divides the body or organ horizontally, into superior and inferior portions, or top and bottom. Diagrams from this perspective can be quite disorienting. Think of this plane in terms of a body opened at the waist like taking a lid off a box; viewing a transverse diagram is like peering down at the box’s contents (and trying to not be disappointed that there’s no puppy inside).
The three planes provide an important reference; but don’t expect the structures of the body, and especially the joints, to line up or move along the standard planes. It’s also important to note that anatomical planes don’t always create two equal portions, and to further complicate matters, they can also “pass through” the body at an angle, which is called an oblique section. Additionally, any cylindrical structure, such as blood vessels or intestines, can be cut straight across (a cross section) or lengthwise (a longitudinal section).
Illustration by Kathryn Born, MA
FIGURE 1-2: Planes of the body: frontal, sagittal, and transverse.
Mapping the regions
The anatomical planes orient you to the human body, but the regions compartmentalize it. Just like on a map, a region refers to a certain area. The body is divided into two major portions: axial and appendicular. The axial body runs right down the center (axis) and consists of everything except the limbs, meaning the head, neck, thorax (chest and back), abdomen, and pelvis. The appendicular body consists of appendages, otherwise known as upper and lower extremities (which you call arms and legs). The proper terms for all the body’s regions are shown in Figures 1-3 and 1-4.
Illustration by Kathryn Born, MA
FIGURE 1-3: The body’s regions: Anterior view.
It’s helpful to practice these terms both visually (on a diagram) and descriptively, especially since you’ll see them popping up throughout this book.
Additionally, the abdomen is divided into quadrants and regions. The midsagittal plane and a transverse plane intersect at an imaginary axis passing through the body at the umbilicus (navel or belly button). This axis divides the abdomen into quadrants (four sections). Putting an imaginary cross on the abdomen creates the right upper quadrant, left upper quadrant, right lower quadrant, and left lower quadrant. Physicians take note of these areas when a patient describes symptoms of abdominal pain.
Illustration by Kathryn Born, MA
FIGURE 1-4: The body’s regions: Posterior view.
The regions of the abdominopelvic cavity include the following:
Epigastric:
The central part of the abdomen, just above the navel.
Hypochondriac:
Doesn’t moan about every little ache and illness, but lies to the right and left of the epigastric region and just below the cartilage of the rib cage. (
Chondral
means
cartilage,
and
hypo
means
below.
)
Umbilical:
The area around the umbilicus.
Lumbar:
Forms the region of the lower back to the right and left of the umbilical region.
Hypogastric:
Below the stomach and in the central part of the abdomen, just below the navel.
Iliac:
Lies to the right and left of the hypogastric regions near the hip bones.
Casing your cavities
Now let’s dig a little deeper. When looking at the body regions of our trunk, there’s more organization to be considered. We can’t just shove all our internal organs between some muscles and fat; neither could we pick them all up and just pile them in a big, empty space. To house all these organs, our body must create structured spaces to hold them. We have two cavities that achieve this purpose: the dorsal cavity, which holds the brain and spinal cord, and the ventral cavity, which holds everything else. The dorsal cavity splits into the vertebral (spinal) cavity, which holds the spinal cord, and the cranial cavity, which houses the brain. The ventral cavity is split into the thoracic cavity and the abdominopelvic cavity by a large band of muscle called the diaphragm. Within the thoracic cavity are the right and left pleural cavities, which hold each lung, and the mediastinum. Within the mediastinum is the pericardial cavity, which contains the heart, the trachea, esophagus, and thymus gland. (The organs listed are within the mediastinum but not the pericardial cavity, it's misleading with the edits that were made.) The abdominopelvic cavity divides into the abdominal cavity (with the stomach, liver, and intestines) and the pelvic cavity (with the bladder and reproductive organs), though there’s no distinct barrier between the two.
Serous membranes are created to define the cavities, lining the walls and covering the organs contained within. The thin layers release a slippery (serous) fluid that reduces friction. The visceral membrane lies atop of the organs, making direct contact with them. The outermost layer of the heart, for example, is called the visceral pericardium, and on the lungs, that layer is the visceral pleura. The parietal membrane lies on the other side of the spaces or lining the cavity itself. So the lining of the abdominopelvic cavity is known as the parietal peritoneum. (Note that it’s not the parietal abdominopelvic, that just sounds weird.)
When identifying the layers of the body cavities, visually or descriptively, it helps to think of the terms instead of the structures. That is, you have two columns of information:
Layer
Place
parietal (wall)
pericardial (heart)
visceral (organ)
pleural (lungs)
cavity (space)
peritoneal (everything else)
Everything is identified by choosing one word from each column. That’s much easier than remembering nine structures.
Getting Organized
When you think about learning anatomy and physiology, you likely think about humans as organisms — living beings that function as a whole. Then you might recall learning in grade school about the levels of organization of our bodies:
organism ← organ systems ← organs ← tissues ← cells ← molecule
“Wait,” you might say. “I thought there were only five levels of organization, so why are there six here? And why are the arrows backward?”
Traditionally, scientists have ended the levels with cells — the smallest things that can be considered to be alive. It doesn’t take a long swim in the pool of physiology, though, to see that our bodies’ actions are carried out by macromolecules, such as proteins, or even just ions (Chapter 2 discusses what those things are) — hence, the six levels. Sometimes, you’ll see atoms added as the seventh level.
About those backward arrows: You often see the levels of organization listed in the opposite order. A group of cells working together to achieve the same goal is a tissue, a group of tissues working together creates an organ, and so on. In this section, though, I start with you — your whole self. Then I’ll break you down and build you back up as the book progresses.
Level 1: The organism level
This level is the real you; the good, the bad, and the ugly (I mean, beautiful). The entire context of anatomy and physiology is looking at how all the structures support you on the organism level, keeping you the best version of yourself that you can be!
Level 2: The organ system level
Human anatomists and physiologists have divided the human body into organ systems — groups of organs that work together to meet a major physiological need. The digestive system, for example, is the organ system responsible for obtaining energy from the environment. Realize, though, that this isn’t a classification system for your organs. That is, each organ isn’t placed in a single system; the systems are defined by the function they carry out. Organs can “belong” to more than one system. The pancreas, for example, produces enzymes that are vital to the breakdown of our food (digestive system), as well as hormones to maintain the balance of the body’s many chemicals (endocrine system).
The chapter structure of this book is based on the definition of organ systems.
Level 3: The organ level
An organ is a group of tissues (at least two types) assembled to perform a specialized physiological function. The stomach, for example, is an organ that has the function of breaking down food, and the function of the biceps muscle is to move your forearm. This level is where the labeling fun begins. If only it were also where it ends!
Level 4: The tissue level
A tissue is a structure made of many cells — sometimes many different kinds of cells — that performs a specific function. Tissues are divided into four categories:
Connective tissue
serves to support body parts and bind them together. Tissues as different as bone and fat are classified as connective tissue.
Epithelial tissue (epithelium)
lines and covers organs, and also carries out absorption and secretion. The outer layer of the skin is made up of epithelial tissue.
Muscle tissue
— surprise! — is found in the muscles (which allow your body parts to move), in the walls of hollow organs (such as intestines) to help move their contents along, and in the heart to move blood throughout the body. (Find out more about muscles in
Chapter 7
.)
Nervous tissue
carries out communication within out body. Nerves and the brain are made of nervous tissue. (I talk about the nervous system in
Chapter 8
.)
Level 5: The cellular level
If you examine a sample of any human tissue under a microscope, you see cells, possibly millions of them. All living things are made of cells. The work of the body actually occurs within the cells. Your whole heart beats to push blood around your body because the muscle cells that create its walls shorten, causing the heart to contract.
Level 6: The molecular level
Though you can’t see molecules without an incredibly powerful microscope, the creation and interaction of them “do our physiology.” Those heart muscle cells that shorten to cause contraction do so because the molecules (proteins) inside the cell pull on each other, causing them to overlap. Even the familiar organelles of a cell are just organized collections of molecules.
Following that logic, that’s all any of us are – just a bunch of molecules hanging out. That concept kind of blows your mind — or, well, your molecules — doesn’t it?
That was a lot of new terms for just the first chapter! Take a moment now to see how they’re sticking.
Whaddya Know? Chapter 1 Quiz
Quiz time! Complete each problem to test your knowledge on the various topics covered in this chapter. You can find the solutions and explanations in the next section.
1 Fill in Table 1-2 with the common and proper terms of your body’s regions.
Table 1-2 The Body’s Regions
Proper Term
Common Term
Proper Term
Common Term
ankle
shin
Coxal
shoulder
Popliteal
Frontal
upper arm
forearm
eye
Mental
Plantar
Carpal
calf
Axillary
head
foot
hand
Otic
Femoral
Sternal
Lumbar
Antecubital
elbow
Bucchal
neck
fingers/toes
For questions 2–11, label the body cavities illustrated in Figure 1-5.
Illustration by Kathryn Born, MA
FIGURE 1-5: Body cavities.
2 _____________________
3 _____________________
4 _____________________
5 _____________________
6 _____________________
7 _____________________
8 _____________________
9 _____________________
10 _____________________
11 _____________________
For questions 12–15, identify the statement as true or false. When the statement is false, identify the error.
12 The cephalic region is considered to be part of the appendicular body.
________________________________________________________
13 The heart is located within the mediastinum, which is an area within the thoracic cavity.
________________________________________________________
14 An organ, by definition, has to be made up of at least two different tissues.
________________________________________________________
15 The terms right and left are dictated by the observer’s perspective when the body is in anatomical position.
________________________________________________________
16 Which of the following correctly matches the section term with the description? Choose all that apply:
(a) Frontal: separates anterior from posterior
(b) Sagittal: separates left from right
(c) Longitudinal: separates lengthwise
(d) Transverse: separates superior from inferior
(e) Oblique: separates at an angle
17 Why don’t we stop at cells when breaking down our bodies’ levels of organization?
________________________________________________________
________________________________________________________
________________________________________________________
FIGURE 1-6: Abdominal regions.
For questions 18–21, identify the abdominal regions by writing the corresponding letter from Figure 1-6.
18 _____ Left lumbar
19 _____ Hypogastric
20 _____ Iliac
21 _____Hypochondriac
To complete questions 22–26, fill in the correct directional terms.
22 The nose is ____________ to the eyes.
23 The rib cage is ____________ to the lungs.
24 The fingers are ____________ wrist.
25 The back is ____________ to the chest.
26 The shoulders are ____________ to the knees.
For questions 27–32, match the descriptions to identify the membranes that create the body’s cavities:
Parietal pericardium
Parietal peritoneum
Parietal pleura
Visceral pericardium
Visceral peritoneum
Visceral pleura
27 _____ The outermost layer encasing the heart
28 _____ The membrane that lies on the surface of the liver
29 _____ The surface of the heart
30 _____ The lining of the thoracic cavity
31 _____ The membrane that makes direct contact with the lungs
32 _____ The layer that lines the abdominopelvic cavity
Answers to Chapter 1 Quiz
1 Here is the completed table:
Proper Term
Common Term
Proper Term
Common Term
Tarsal
ankle
Crural
shin
Coxal
hip
Scapular
shoulder
Popliteal
back of knee
Frontal
forehead
Brachial
upper arm
Antebrachial
forearm
Orbital
eye
Mental
chin
Plantar
sole/bottom of foot
Carpal
wrist
Sural
calf
Axillary
armpit
Cephalic
head
Pedal
foot
Manual
hand
Otic
ear
Femoral
thigh
Sternal
breastbone/sternum
Lumbar
lower back
Antecubital
inner elbow
Cubital
elbow
Bucchal
cheek
Cervical
neck
Digital
fingers/toes
2Ventral.
3Dorsal.
4Thoracic.
5Abdominopelvic or peritoneal.
6Cranial.
7Spinal or vertebral.
8Pleural.
9Pericardial. It’s within the thoracic cavity but not within the pleural cavity.
10Abdominal.
11Pelvic. There is not a structure that clearly marks the border between the abdominal and pelvic cavities.
12False. It’s part of the axial skeleton. Appendicular is appendages, or arms and legs.
13True. The mediastinum contains everything within the thoracic cavity that isn’t inside the pleural cavity.
14True.
15False. Although anatomical position is important here, it’s the patient’s right and left, not yours.
16All the statements are accurate. You didn’t question yourself for that reason, did you?
Don’t question your knowledge or your gut when you notice a pattern like this one, or like answering (a) five times in a row. Odds are that the test writer either didn’t pay attention to patterns or created one on purpose to mess with you, as I just did.
17It’s true that cells are the smallest structures considered to be alive. Some organisms are themselves single-cell organisms (like bacteria). Obviously, we aren’t single-celled, but that’s why you’ve previously learned that cells are the smallest level of organization. In the context of physiology, however, the cells aren’t what’s changing to carry out functions; it’s the molecules contained inside of them. That’s the reason for the sixth level, which is molecules; they carry out the work.
18F.
19H.
20G or I. G is the right iliac, and I is the left.
21A or C. A is the right hypochondriac, and C is the left.
22Medial.
23Superficial. Not anterior! The ribs aren’t in front of the lungs; they surround them.
24Distal.
25Posterior or dorsal.
26Superior. Though the shoulders and the knees are both on appendages, they’re not on the SAME one, so you wouldn’t use proximal/distal.
27(a) Parietal pericardium.
28(e) Visceral peritoneum.
29(d) Visceral pericardium.
30(c) Parietal pleura.
31(f) Visceral pleura.
32(b) Parietal peritoneum.
Don’t memorize all nine terms (cavities included), memorize the naming system. The space is always the cavity, and the visceral layer always makes direct contact with an organ. The pattern holds true everywhere except the brain and spinal cord; they’re special.
Chapter 2
Better Living through Chemistry
IN THIS CHAPTER
Getting to the heart of all matter: Atoms
Learning about building with your blocks
Making sense of metabolism
Exploring our body’s energy
Ican hear your cries of alarm. You thought you were getting ready to learn about the knee bone connecting to the thigh bone. How in the heck does that involve (horrors!) chemistry? As much as you may not want to admit it, chemistry — particularly organic chemistry, the branch of the field that focuses on carbon-based molecules — is a crucial starting point for understanding how the human body works.
There is, however, no agreed-upon baseline of chemistry understanding you need to fully grasp the body’s physiological processes. Different instructors will hold you to different standards. The expectation, though, is that students enrolled in an anatomy and physiology (A&P) course have had at least a high-school-level course in chemistry. In this chapter, I walk you through what I think is essential background knowledge for success in A&P courses, based on my own experience teaching them.
When it comes to chemistry, what matters most is knowing that the things happen, not understanding how or why they happen. Don’t let the details bog you down. Should you find yourself in a course whose instructor expects a lot more from you in terms of chemistry knowledge, I highly recommend checking out Chemistry For Dummies, 2nd Edition, by John T. Moore (John Wiley & Sons, Inc.).
What’s the Matter?
Remember the periodic table? That big chart of elements that you may have had to memorize? Fortunately, you don’t need to do that here (phew!); you only need to know why it has so many letters. Each box represents an element, the fundamental unit making up all stuff on Earth. That stuff is what we call matter. Elements are like LEGOs: They come in many shapes, sizes, and colors, but are all made of the same plastic and attach together in the same way. Each variety of brick, a red 4x2 rectangle for example, is an element; we’ll say that’s carbon. There are also little, blue 2x1 blocks, which could be hydrogen. You could click the LEGOs together easily and make, say, a couch. Bring in more bricks of different elements, and you could build a room — a whole house even. You could randomly decide to remodel and be done quickly. You could bring in other contractor LEGO builders to help you do the work faster. The analogy is starting to get a bit out of control here, but the point is this: Physiology is just like playing with LEGOs. Each brick is an atom, and the atoms are clicked together (making a bond) to create molecules — the innumerable structures you can build.
So that’s you … a bunch of LEGO furniture assembled into houses (cells), which are organized into neighborhoods (tissues), which create LEGO cities (organs), which link to form states (body systems) and finally a big LEGO you! (Are you imagining what you’d look like if you were made of LEGOs?!)
You often see the word molecule used interchangeably with the term compound. True, both things are made of connected atoms. But compounds by definition include atoms of different elements (different shapes and colors of LEGOs). Molecules are any elements linked together, even if it’s just two Hydrogens (the simplest molecule possible).
So all compounds are considered to be molecules, but not all molecules are compounds. Be careful with the difference, because the words don’t mean exactly the same thing.
Now, of course, building molecules is far more complicated than that. Some LEGOs just won’t attach to others because of their unseen structures in our analogy. (You’ve gotta use your imagination here.) They’re all made of the same three components: protons (positively charged particles), neutrons (neutral), and electrons (negative). The numbers of these particles make the elements (LEGO blocks) different and influence how they behave (which other LEGOs they’ll attach to).
Here’s what matters most about this matter:
The number of protons defines the element.
Protons will never be lost or gained, as the change would make the atom a different element. (This change is possible, but not in the human body; it’s what happens in nuclear fission and fusion.)
Electrons move around in a cloud that surrounds the atom’s nucleus.
The
nucleus
is the center mass where the protons and neutrons (which don’t move) reside. For this reason, electrons can interact with other atoms and their electrons. So when you attach two atoms, you create a bond. Often, the atoms share the electrons, creating what is called a
covalent bond
.
If you have that information down, you’ll feel much more comfortable as this chapter progresses.
Keep Your Ion the Prize
All the molecules that make us up are going to interact, staying put to create our structures and moving around to perform the reactions that keep us alive. Large compounds to single atoms all have their roles to play.
Try on some ions
Some atoms never really grasped the old “sharing is caring” adage. They end up grabbing electrons wherever they’re able to and keeping them to themselves; they’re greedy. Because electrons are negatively charged, now the entire atom is negatively charged, or an anion. Other ions are martyrs, readily giving up electrons to the greedy atoms. These ions become positively charged, or cations.
Sodium (Na), for example, is an electron donor, becoming a cation: Na+. Chlorine is an electron acceptor, becoming an anion: Cl-. Just like with magnets, the opposite charges attract. This connection, called an ionic bond, is another way to build molecules. In this case, we get NaCl, which you know as the delicious little white crystals you like to sprinkle on your food (table salt).
