4.0 Introduction

This micrograph shows tissue surrounding several empty spaces. The epithelial tissue occurs at the border between the rest of the tissue and the empty spaces. The normal epithelium is composed of rectangular-shaped cells neatly organized side by side. Dark purple nuclei are clear at the bottom of the epithelial cells, where they attach to the rest of the tissue. The abnormal epithelium appears as a tangled area of purple nuclei, much thicker than the normal epithelium although no distinct cells are discernible.
Figure 4.0 – Micrograph of Cervical Tissue: This figure is a view of the regular architecture of normal tissue contrasted with the irregular arrangement of cancerous cells. (credit: “Haymanj”/Wikimedia Commons)


Chapter Objectives

After studying this chapter, you will be able to:


4.1 – Identify the main tissue types and discuss their roles in the human body.

4.2 – Describe the structural characteristics of the various epithelial tissues and how these characteristics enable their functions.

4.3 – Describe the structural characteristics of the various connective tissues and how these characteristics enable their functions.

4.4 – Describe the characteristics of muscle tissue and how these dictate muscle function.

4.5 – Describe the characteristics of nervous tissue and how these enable the unique functions of nervous tissue.

4.6 – Describe the process of tissue response to injury.

The cells found in the human body contain essentially the same internal structures yet they vary enormously in shape and function. The variation in cells is not randomly distributed throughout the body, rather, they occur in organized layers.  Such aggregations of cells that are similar in structure and work together to perform a specialized function are referred to as tissues.  The micrograph that opens this chapter shows the high degree of organization among different types of cells in the tissue of the cervix. You can also see how that organization breaks down when cancer takes over the regular mitotic functioning of a cell.

The human body starts as a single cell at fertilization. As this fertilized egg divides, it gives rise to trillions of cells, each built from the same blueprint, but organizing into tissues and becoming irreversibly committed to a developmental pathway.

This work, Anatomy & Physiology, is adapted from Anatomy & Physiology by OpenStax, licensed under CC BY. This edition, with revised content and artwork, is licensed under CC BY-SA except where otherwise noted.

Images, from Anatomy & Physiology by OpenStax, are licensed under CC BY except where otherwise noted.

Access the original for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction.


Icon for the Creative Commons Attribution-ShareAlike 4.0 International License

Anatomy & Physiology Copyright © 2019 by Lindsay M. Biga, Staci Bronson, Sierra Dawson, Amy Harwell, Robin Hopkins, Joel Kaufmann, Mike LeMaster, Philip Matern, Katie Morrison-Graham, Kristen Oja, Devon Quick, Jon Runyeon, OSU OERU, and OpenStax is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License, except where otherwise noted.