-
8/12/2019 Lecture 10 Muscle Histology Titus
1/12
Muscle Histology
-
8/12/2019 Lecture 10 Muscle Histology Titus
2/12
Types of Muscle Tissue
Skeletal muscle
Cardiac muscle
Smooth muscle
-
8/12/2019 Lecture 10 Muscle Histology Titus
3/12
Types of Muscle Tissue
SkeletalAttach to and move skeleton
40% of body weightFibers = multinucleate cells (embryonic cells
fuse)
Cells with obvious striations
Contractions are voluntary
Cardiac:only in the wall ofthe heart
Cells are striated
Contractions are
involuntary (notvoluntary)
Smooth:walls of hollow organsLack striations
Contractions are involuntary (notvoluntary)
-
8/12/2019 Lecture 10 Muscle Histology Titus
4/12
Similarities
Their cells are called fibersbecause they
are elongated
Contraction depends on myofilaments
Actin
Myosin
Plasma membrane is called sarcolemma
Sarcos= flesh
Lemma= sheath
-
8/12/2019 Lecture 10 Muscle Histology Titus
5/12
Types of skeletal muscle fibers
Fast, slow and intermediate
Whether or not they predominantly use oxygen toproduce ATP (the
energy molecule used in musclecontraction) Oxidative aerobic (use
oxygen)
Glycolytic make ATP by glycolysis (break down of sugarswithout
oxygen=anaerobic)
Fast fibers: white fiberslarge, predominantlyanaerobic, fatigue
rapidly (rely on glycogen reserves);most of the skeletal muscle
fibers are fast
Slow fibers: red fibershalf the diameter, 3X slower,but can
continue contracting; aerobic, more mitochondria,myoglobin
Intermediate: in between
-
8/12/2019 Lecture 10 Muscle Histology Titus
6/12
Type 1 muscle fibers are high in oxidative
activity, low in glycolytic activity and are
red grossly because of a high content of
myoglobin and mitochondrial cytochromes.They contract slowly,
but are capable of
repeated or continuous contraction. The
mnemonic "ONE SLOW RED OX*"provides a useful image to help
remember
the characteristics of this fiber type.
-
8/12/2019 Lecture 10 Muscle Histology Titus
7/12
Type 2 muscle fibers are low in oxidative
activity and high in glycolytic activity. They
are white grossly and are capable of rapid
contraction, but cannot maintain repeatedcontraction
indefinitely. The mnemonic
"TWO FAST WHITE SUGAR*"helps
recall these features. Remembering thesesimple details
demystifies the otherwise
bewildering array of histochemical stains
that can be applied to frozen sections of
-
8/12/2019 Lecture 10 Muscle Histology Titus
8/12
ATPase pH 9.4 (Light-type1)
-
8/12/2019 Lecture 10 Muscle Histology Titus
9/12
NADH-TR(dark-type1)
-
8/12/2019 Lecture 10 Muscle Histology Titus
10/12
SDH(blue mitochondria)
-
8/12/2019 Lecture 10 Muscle Histology Titus
11/12
As a general rule, a "checkerboard"
appearance is the norm, with no single
muscle fiber entirely surrounded by
muscle fibers of its own type. Whengroups occur and are
well-developed, the
question of denervation-reinnervation must
be raised.
-
8/12/2019 Lecture 10 Muscle Histology Titus
12/12
Abnormal type1&2 formation
