Muscle Tissue Histology
Cross Section of a Skeletal Muscle
• Blue =
epimysium
• Green =
perimysium
• Yellow =
endomysium
surrounding
muscle fiber
Pointer is on the perimysium surrounding
a muscle fascicle
Epimysium would be here
surrounding the entire muscle
organ (but it is not visible on the
slide)
Skeletal Muscle Cross
Section Slide
Skeletal Muscle Cross
Section Slide
Muscle fascicles can be a
variety of shapes!
Pointer is on the perimysium
surrounding a muscle fascicle
Skeletal Muscle Cross
Section Slide
black arrows are pointing at
individual skeletal muscle fibers
Multinucleated Skeletal Muscle Fibers
The small purple dots are the nuclei of
a skeletal muscle fiber. Notice that
each fiber has more than 1 nucleus?
Skeletal Muscle Long Section
• Each
bracket
is on one
Skeletal
Muscle
Fiber
(cell)
Skeletal Muscle: Striations
Skeletal muscle fibers are clearly
striated with dark A-bands and light
I-bands
Skeletal Muscle Long Section:
Multinucleated
Skeletal muscle fibers are
multinucleated (they have more
than 1 nucleus per cell)
Cardiac Muscle
• Striations
• Nuclei
• Intercalated discs
black arrows are pointing at
intercalated discs (only found
on cardiac muscle)
Smooth Muscle
• Nuclei
Smooth
muscle cells
Smooth muscle cells have a
spindle shape and only one
nucleus per cell with NO striations!
Motor Unit = a somatic motor neuron +
skeletal muscle fibers it synapses with
Motor Unit Slide
• Green =
Neuromuscular
Junction
• Yellow = Axon of a
somatic motor
neuron
• White = skeletal
muscle fiber
Motor Unit Slide
Pointer is on the axon
of a somatic motor
neuron
Green arrow is on a
neuromuscular junction
Motor Unit