Chapter 4
Tissue: The Living Fabric
117
4
Preparing Human Tissue
for Microscopy
List the steps involved in preparing animal tissue for
microscopic viewing.
Microscopy allows us to study tissue structure. Before a spec-
imen can be viewed through a microscope, it must be
fixed
(preserved) and then cut into
sections
(slices) thin enough
to transmit light or electrons. Finally, the specimen must be
stained
to enhance contrast.
Te stains used in light microscopy are beautifully colored or-
ganic dyes, most of which were originally developed by clothing
the “fabric” of the body. Tese basic tissues are epithelial,
connective, nervous, and muscle tissue.
If we summarized the role of each primary tissue in a single
word, we could say that epithelial tissue
covers
, connective tis-
sue
supports
, nervous tissue
controls
, and muscle tissue
produces
movement.
However, these words reveal only a fraction of what
each tissue does
(Figure 4.1)
.
As we explained in Chapter 1, tissues are organized into or-
gans such as the kidneys and heart. Most organs contain all four
tissue types, and their arrangement determines the organ’s struc-
ture and capabilities. Te study of tissues, or
histology
, com-
plements the study of gross anatomy. ±ogether they provide the
structural basis for understanding organ physiology.
Nervous tissue:
Internal communication
• Brai
n
• Spinal cor
d
• Ne
rves
Muscle tissue:
Contracts to cause movement
• Muscles at
tached to bones (skeletal)
• Muscles of hea
rt (cardiac)
• Muscles of
wa
lls of hollo
w organs (smooth)
Epithelial tissue:
Forms boundaries betw
een diffe
rent
environments
, pr
otects, secretes, absorbs,
fi
lters
• Lining of digestiv
e tract organs and other hollow
organs
• Skin surface (epider
mis)
Connective tissue:
Suppor
ts
, pr
otects, binds
other tissues together
• Bones
Tendons
• Fat and other soft padding tissue
Figure 4.1
Overview of four basic tissue types: epithelial, connective, muscle, and
nervous tissues.
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