Chapter 4
Tissue: The Living Fabric
139
4
(b)
Cardiac muscle
Description:
Branching, striated, generally
uninucleate cells that interdigitate at
specialized junctions (intercalated discs).
Function:
As it contracts, it propels blood
into the circulation; involuntary control.
Location:
The walls of the heart.
Photomicrograph:
Cardiac muscle (900
m
);
notice the striations, branching of cells, and
the intercalated discs.
Intercalated
discs
Striations
Nucleus
Figure 4.9
(continued)
(b)
Cardiac muscle tissue. (For a related image, see
A Brief Atlas of the Human Body
,
Plate 31.)
(c)
Smooth muscle tissue. (For a related image, see
A Brief Atlas of the Human Body
, Plate 32.
(c)
Smooth muscle
Description:
Spindle-shaped cells with
central nuclei; no striations; cells arranged
closely to form sheets.
Function:
Propels substances or objects
(foodstuffs, urine, a baby) along internal
passageways; involuntary control.
Location:
Mostly in the walls of hollow
organs.
Photomicrograph:
Sheet of smooth muscle (720
m
).
Smooth
muscle
cell
Nuclei
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