The Plasma Membrane

The electron microscope reveals that the cell and many of the organelles within it are bordered by a unit membrane, which appears as a pair of dark parallel lines with a total thickness of about 7.5 nm (fig. 3.6a). The plasma membrane is the unit membrane at the cell surface. It defines the boundaries of the cell, governs its interactions with other cells, and controls the passage of materials into and out of the cell. The side that faces the cytoplasm is the intracellular face of the membrane, and the side that faces outward is the extracellular face.

Saladin: Anatomy & I 3. Cellular Form and I Text I © The McGraw-Hill

Physiology: The Unity of Function Companies, 2003 Form and Function, Third Edition

Chapter 3 Cellular Form and Function 99

Chapter 3 Cellular Form and Function 99

Phospholipid Cell

Nonpolar tails of phospholipid of phospholipid molecules molecules

Nonpolar tails of phospholipid of phospholipid molecules molecules

Cytoplasm

Figure 3.6 The Plasma Membrane. (a) Plasma membranes of two adjacent cells (electron micrograph). (b) Molecular structure of the plasma membrane.

Was this article helpful?

0 0
Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

Get My Free Ebook


Post a comment