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Essentials of Human Anatomy & Physiology [Global Edition] 13th Edition



Essentials of Human Anatomy & Physiology [Global Edition] 13th Edition PDF

Author: Elaine Marieb and Suzanne Keller

Publisher: Pearson

Genres:

Publish Date: April 21, 2021

ISBN-10: 129240194X

Pages: Pages

File Type: PDF

Language: English


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downloadreadPDFOctober 26, 2021

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Book Preface

Most of us are naturally curious about our bodies; we want to know what makes us tick. Infants  can keep themselves happy for a long time staring  at their own hands or pulling their mother’s nose.  Older children wonder where food goes when they  swallow it, and some believe that they will grow a  watermelon in their belly if they swallow the seeds.

Adults become upset when their hearts pound, when  they have uncontrollable hot flashes, or when they  cannot keep their weight down. Anatomy and physiology, subdivisions of biology, explore many of these topics as they describe  how our bodies are put together and how they work.

Anatomy
Anatomy (ah-nat’o-me) is the study of the structure  and shape of the body and its parts and their relationships to one another. Whenever we each look at our  own body or study large body structures such as the  heart or bones, we are observing gross anatomy; that  is, we are studying large, easily observable structures.

Indeed, the term anatomy, derived from the Greek  words meaning to cut (tomy) apart (ana), is related  most closely to gross anatomical studies because in  such studies, preserved animals or their organs are  dissected (cut up) to be examined. Microscopic anatomy, in contrast, is the study of body structures that  are too small to be seen with the naked eye. The cells  and tissues of the body can only be seen through a microscope.

Physiology

Physiology (fiz”e-ol’o-je) is the study of how the  body and its parts work or function (physio 5 nature; ology 5 the study of). Like anatomy, physiology has  many subdivisions. For example, neurophysiology explains the workings of the nervous system, and  cardiac physiology studies the function of the heart.

Anatomy and Physiology

Anatomy and physiology are always inseparable.
The parts of your body form a well-organized unit,  and each of those parts has a job to do to make the  body operate as a whole. Structure determines what  functions can take place. For example, the lungs are  not muscular chambers like the heart and so cannot pump blood through the body, but because the  walls of their air sacs are very thin, they can exchange  gases and provide oxygen to the body. We stress the  intimate relationship between anatomy and physiology throughout this text to make your learning  meaningful

The human body exhibits many levels of structural complexity (Figure 1.1). The simplest level of  the structural ladder is the chemical level (covered  in Chapter 2). At this level, atoms, tiny building  blocks of matter, combine to form molecules such as  water, sugar, and proteins, like those that make up  our muscles. Molecules, in turn, associate in specific ways to form microscopic cells, the smallest  units of all living things. (We will examine the cellular level in Chapter 3.) All cells have some common structures and functions, but individual cells  vary widely in size, shape, and their particular roles  in the body.

The simplest living creatures are composed of single cells, but in complex organisms such as trees  or human beings, the structural ladder continues  on to the tissue level. Tissues consist of groups of  similar cells that have a common function. There  are four basic tissue types, and each plays a definite  but different role in the body. (We discuss tissues in Chapter 3.)

An organ is a structure composed of two or  more tissue types that performs a specific function  for the body. At the organ level of organization,  extremely complex functions become possible. For  example, the small intestine, which digests and  absorbs food, is composed of all four tissue types. An  organ system is a group of organs that work  together to accomplish a common purpose. For  example, the heart and blood vessels of the cardiovascular system circulate blood continuously to carry  nutrients and oxygen to all body cells. In all, 11 organ systems make up the living  human being, or the organism, which represents the  highest level of structural organization, the organismal  level. The organismal level is the sum total of all structural levels working together to keep us alive. The major organs of each system are shown in Figure 1.2 on pp. 27–28. Refer to the figure as you read through the following descriptions of the organ systems.


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