are found in the brain, spinal cord,
and peripheral nerves. The basic cells are called
they are highly specialized. Neurons sense certain types of
changes in their surroundings and respond by transmitting
nerve impulses along cellular processes called
neurons or to muscles or glands
(f g. 5.31)
. As a result of the
extremely complex patterns by which neurons connect with
each other and with muscle and gland cells, they can coordi-
nate, regulate, and integrate many body functions.
In addition to neurons, nervous tissue includes abun-
shown in F
gure 5.31. These cells support and
bind the components of nervous tissue, carry on phagocyto-
sis, and help supply growth factors and nutrients to neurons
by connecting them to blood vessels. They also play a role
Cardiac Muscle Tissue
Cardiac muscle tissue
is only in the heart
(f g. 5.30)
. Its cells,
striated and branched, are joined end-to-end, and intercon-
nected in complex networks. Each cardiac muscle cell has a
single nucleus. Where one cell touches another cell is a spe-
cialized intercellular junction called an
only in cardiac tissue.
Cardiac muscle, like smooth muscle, is controlled invol-
untarily. Cardiac muscle can continue to function without
being stimulated by nerve impulses. This tissue makes up
the bulk of the heart and pumps blood through the heart
chambers and into blood vessels.
List the general characteristics of muscle tissue.
Distinguish among skeletal, smooth, and cardiac muscle tissues.
Smooth muscle tissue consists of spindle-shaped cells, each with a large nucleus (1,000×).
Cardiac muscle cells are branched and interconnected, with a single nucleus each (400×).