WGU CHAPTER 4 LAB BIO 210 LABORATORY LATEST STUDY GUIDE
2026
Chapter 4: Tissues
Cells are the building blocks of life. In humans and other multicellular organ isms, cells depend
on one another and cooperate to maintain homeostasis in the body.
With a few exceptions, even the most complex animal starts out as a single cell, the fertilized
egg, which divides almost endlessly. The resulting trillions of cells then specialize for a particular
function. Some become supportive bone, others skin cells, and so on. Thus, a division of labor
exists, with certain groups of cells highly specialized to perform functions that benefit the
organism as a whole. Cell specialization provides for sophisticated functions but involves certain
hazards, because when a small, specific group of cells is indispensable, any inability to function
on its part can paralyze or destroy the entire body.
Groups of cells that are similar in structure and function are called tissues. The four primary
tissue types—epithelial, connective, muscular, and nervous— have distinct structures, patterns,
and functions.
To perform specific body functions, the tissues are organized into organs such as the heart,
kidneys, and lungs. Most organs contain several representatives of the primary tissues, and the
arrangement of these tissues determines the organ’s structure and function. The main
objective of this exercise is to familiarize you with the major similarities and dissimilarities of
the primary tissues.
Exercise 1: Complete the following related to tissues.
Define tissue:
Use the key choices to identify the major tissue types described below.
Epithelium Connective Muscular Nervous
1. Lines body cavities and covers the body’s external surface
2. Pumps blood, flushes urine out of the body, allows one to swing a bat
3. Transmits waves of excitation
4. Anchors and packages body organs
5. Cells may absorb, protect, or for a filtering membrane
6. Most involved in regulating body functions quickly
7. Major function is to contract
8. Most durable of tissue types
9. Abundant nonliving extracellular matrix
10. Forms nerves
, Epithelial Tissue
Epithelial tissues, or epithelia, cover or line surfaces. For example, epithelia cover the external
body surface (as the epidermis), line its cavities, and generally mark off our “insides” from our
outsides. Because glands of the body almost always develop from epithelial membranes, glands
too are classed as epithelia.
Epithelial functions include protection, absorption, filtration, excretion, secretion, and
sometimes sensory reception. For example, the epithelium covering the body protects against
bacterial invasion and chemical damage; that lining the respiratory tract is ciliated to sweep
dust and other foreign particles away from the lungs. Secretion is a specialty of the glands, and
taste receptors are epithelial cells.
Epithelia generally exhibit these characteristics:
• Cells fit closely together to form membranes, or sheets of cells, and are bound together
by specialized junctions.
• The membranes always have one exposed surface or free edge, called the apical
surface.
• The cells are attached to and supported by an adhesive basement membrane, a
material secreted collectively by the epithelial cells and the connective tissue cells that
lie next to each other.
• Epithelial tissues have no blood supply of their own (are avascular), but depend on
diffusion of nutrients from the underlying connective tissue. (The exception is glandular
epithelial tissue, which is very vascular.)
• If well nourished, epithelial cells can easily regenerate themselves. This is an important
characteristic because many epithelia are subjected to a good deal of friction and other
types of trauma.
2026
Chapter 4: Tissues
Cells are the building blocks of life. In humans and other multicellular organ isms, cells depend
on one another and cooperate to maintain homeostasis in the body.
With a few exceptions, even the most complex animal starts out as a single cell, the fertilized
egg, which divides almost endlessly. The resulting trillions of cells then specialize for a particular
function. Some become supportive bone, others skin cells, and so on. Thus, a division of labor
exists, with certain groups of cells highly specialized to perform functions that benefit the
organism as a whole. Cell specialization provides for sophisticated functions but involves certain
hazards, because when a small, specific group of cells is indispensable, any inability to function
on its part can paralyze or destroy the entire body.
Groups of cells that are similar in structure and function are called tissues. The four primary
tissue types—epithelial, connective, muscular, and nervous— have distinct structures, patterns,
and functions.
To perform specific body functions, the tissues are organized into organs such as the heart,
kidneys, and lungs. Most organs contain several representatives of the primary tissues, and the
arrangement of these tissues determines the organ’s structure and function. The main
objective of this exercise is to familiarize you with the major similarities and dissimilarities of
the primary tissues.
Exercise 1: Complete the following related to tissues.
Define tissue:
Use the key choices to identify the major tissue types described below.
Epithelium Connective Muscular Nervous
1. Lines body cavities and covers the body’s external surface
2. Pumps blood, flushes urine out of the body, allows one to swing a bat
3. Transmits waves of excitation
4. Anchors and packages body organs
5. Cells may absorb, protect, or for a filtering membrane
6. Most involved in regulating body functions quickly
7. Major function is to contract
8. Most durable of tissue types
9. Abundant nonliving extracellular matrix
10. Forms nerves
, Epithelial Tissue
Epithelial tissues, or epithelia, cover or line surfaces. For example, epithelia cover the external
body surface (as the epidermis), line its cavities, and generally mark off our “insides” from our
outsides. Because glands of the body almost always develop from epithelial membranes, glands
too are classed as epithelia.
Epithelial functions include protection, absorption, filtration, excretion, secretion, and
sometimes sensory reception. For example, the epithelium covering the body protects against
bacterial invasion and chemical damage; that lining the respiratory tract is ciliated to sweep
dust and other foreign particles away from the lungs. Secretion is a specialty of the glands, and
taste receptors are epithelial cells.
Epithelia generally exhibit these characteristics:
• Cells fit closely together to form membranes, or sheets of cells, and are bound together
by specialized junctions.
• The membranes always have one exposed surface or free edge, called the apical
surface.
• The cells are attached to and supported by an adhesive basement membrane, a
material secreted collectively by the epithelial cells and the connective tissue cells that
lie next to each other.
• Epithelial tissues have no blood supply of their own (are avascular), but depend on
diffusion of nutrients from the underlying connective tissue. (The exception is glandular
epithelial tissue, which is very vascular.)
• If well nourished, epithelial cells can easily regenerate themselves. This is an important
characteristic because many epithelia are subjected to a good deal of friction and other
types of trauma.
