165
CHAPTER FIVE
Tissues
Cell
membrane
Nuclei of
neuroglia
Cytoplasm
Cellular
process
Nucleus
(a)
(b)
in cell-to-cell communications. Chapter 10 discusses nervous
tissue.
Table 5.8
summarizes the general characteristics of
muscle and nervous tissues. From Science to Technology 5.2
discusses tissue engineering, part of a ±
eld called regenera-
tive medicine.
PRACTICE
24
Describe the general characteristics of nervous tissue.
25
Distinguish between neurons and neuroglia.
FIGURE 5.31
A neuron with cellular processes extending into its surroundings (350×).
TABLE
5.8
|
Muscle and Nervous Tissues
Type
Description
Function
Location
Skeletal muscle tissue
Long, threadlike cells, striated, many
nuclei
Voluntary movements of skeletal parts
Muscles usually attached to bones
Smooth muscle tissue
Shorter cells, single, central nucleus
Involuntary movements of internal organs
Walls of hollow internal organs
Cardiac muscle tissue
Branched cells, striated, single
nucleus
Heart movements
Heart muscle
Nervous tissue
Cell with cytoplasmic extensions
Sensory reception and conduction of nerve impulses
Brain, spinal cord, and peripheral nerves
The cells of diF
erent tissues vary greatly in their abilities to divide.
Cells that divide continuously include the epithelial cells of the skin,
the inner lining of the digestive tract, and the connective tissue pro-
genitor cells that form blood cells in red bone marrow. However, skel-
etal and cardiac muscle cells and nerve cells do not usually divide at
all after diF
erentiating.
±ibroblasts respond rapidly to injuries by increasing in number
and ²
ber production. They are often the principal agents of repair in
tissues that have limited abilities to regenerate. ±or instance, ²
bro-
blasts form scar tissue after a heart attack occurs.
b. A basement membrane anchors epithelium to
connective tissue. Epithelial tissue lacks blood
vessels, has cells that are tightly packed, and is
continuously replaced.
c. It functions in protection, secretion, absorption,
and excretion.
2. Simple squamous epithelium
a. This tissue consists of a single layer of thin, fl attened
cells through which substances pass easily.
b. It functions in the exchange of gases in the lungs
and lines blood vessels, lymph vessels, and
membranes within the thorax and abdomen.
3. Simple cuboidal epithelium
a. This tissue consists of a single layer of cube-
shaped cells.
CHAPTER SUMMARY
5.1
INTRODUCTION (PAGE 144)
1. Cells are organized in layers or groups to form tissues.
2. Specialized intercellular junctions (tight junctions,
desmosomes, and gap junctions) connect cells.
3. The study of tissues is called histology.
4. The four major types of human tissue are epithelial,
connective, muscle, and nervous.
5.2
EPITHELIAL TISSUES (PAGE 144)
1. General characteristics
a. Epithelial tissue covers all free body surfaces,
forms the inner lining of body cavities, lines
hollow organs, and is the major tissue of glands.
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