Page 153 - Fundamentals of anatomy physiology

Clinical Case Now she has a wide scar over her
eyebrow. She bruises e­ asily, too.
The Rubber Girl
Anne Marie thinks she is a
All her life Anne Marie has felt “delicate.” She is a lot like her dad. He has the same
horrible athlete. She once dislocated both shoul- easy-bruising skin that seems to
ders attempting to play high school volleyball. And she has an tear with minimal trauma and heal
unstable feeling, as if her kneecaps will dislocate, when she tries poorly. He was never very athletic
dancing or any other twisting activity. She sprains one ankle and is also loose jointed. He has
or the other at least once a year. She has always been “double twisted both ankles many times.
jointed,” with fingers that she can bend back until they nearly Luckily he has a desk job. What
touch her dorsal forearm. Her elbows and knees all hyperextend,
moving beyond their normal anatomical position. is the cause of Anne Marie’s
Anne Marie’s skin has always been delicate, pale, and very
stretchy. She seems to get abrasions and cuts easily. These u­ nusual physical traits? To find out, turn to the
heal slowly, leaving huge scars that are also fragile. Once, she
had stitches in her face and they cut right through the skin. Clinical Case Wrap-Up on p. 175.

An Introduction to the Tissue In this chapter we introduce the basic characteristics of
Level of Organization these tissues. This information will help you understand the
descriptions of organs and organ systems in later chapters. It
In this chapter we discuss how a variety of cell types arranged will also help you make the connections between anatomical
in various combinations form tissues, which are structures with structures and their physiological functions. ATLAS: Embryology
discrete structural and functional properties. Tissues in com- Summary 1: The Formation of Tissues
bination form organs, such as the heart or liver, and in turn
organs can be grouped into 11 organ systems. p. 32 Checkpoint
1. Define histology.
4-1 The four tissue types are epithelial, 2. Identify the four major types of tissues in the body.

connective, muscle, and neural See the blue Answers tab at the back of the book.

Learning Outcome Identify the four major types of tissues in the body 4-2 Epithelial tissue covers body
and describe their roles.
surfaces, lines cavities and tubular
The human body contains trillions of cells, but only about structures, and serves essential functions
200 types of cells. To work efficiently, several different types of
cells must coordinate their efforts. Cells working together form Learning Outcome Discuss the types and functions of epithelial tissue.
tissues—collections of specialized cells and cell products
that carry out a limited number of functions. The study of tis- Let’s begin our discussion with epithelial tissue, because
sues is called histology. Histologists recognize four basic types it includes a very familiar feature—the surface of your skin.
of tissue: Epithelial tissue includes epithelia and glands. Epithelia
(ep-i-THE■ -le. -a; singular, epithelium) are layers of cells that
1. Epithelial tissue covers exposed surfaces, lines internal pas- cover internal or external surfaces. Glands are structures
sageways and chambers, and forms glands. that produce fluid secretions. They are either attached to or
derived from epithelia.
2. Connective tissue fills internal spaces, provides structural
support for other tissues, transports materials within the Epithelia cover every exposed surface of your body.
body, and stores energy. ­Epithelia form the surface of the skin and line the digestive,
respiratory, reproductive, and urinary tracts. In fact, they line
3. Muscle tissue is specialized for contraction and includes the all p­ assageways that communicate with the outside world. The
skeletal muscles of the body, the muscle of the heart, and more delicate epithelia line internal cavities and passageways,
the muscular walls of hollow organs. such as the chest cavity, fluid-filled spaces in the brain, the
inner surfaces of blood vessels, and the chambers of the heart.
4. Neural tissue carries information from one part of the body
to another in the form of electrical impulses.

140