Download Muscle Tissue

Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Muscle Tissue
Learning Objectives
Keywords
Slides
A. Types of Muscle
1. Striated
a. Skeletal
b. Cardiac
V.
2. Smooth
B. Muscle Development (Skeletal)
Summary
SEM of partly unraveled skeletal muscle cell exposing the densely packed myofibrils within.
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Slides
A. Types of Muscle
1. Striated
Muscle Tissue
1.
a. Skeletal
b. Cardiac
V.
2. Smooth
B. Muscle Development (Skeletal)
Summary
2.
3.
Muscle is a highly cellular and vascular tissue
specialized for contraction via the interaction of
myofilaments (between thin and thick filaments);
it is responsible for movement of the body and for
changes in the size and shape of internal organs.
There are three basic types of muscle tissue
(skeletal, smooth, and cardiac) classified according
to appearance of their contractile cells and location.
Striated muscle is formed during development by the
fusion of small individual muscle cells called
myoblasts into larger, multinucleated myotubes.
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Slides
A. Types of Muscle
1. Striated
a. Skeletal
b. Cardiac
V.
2. Smooth
B. Muscle Development (Skeletal)
Summary
Learning Objectives
1. Understand the structural features of three general types of muscle cells
and how each is organized to form a contractile tissue that performs
specific types of work.
2. Understand the structural and functional attributes of connective tissues
associated with muscle and the myotendinous junction.
3. Understand that skeletal muscle contains different types of fibers
4. Understand the arrangement of actin and myosin filaments in all three
muscle types.
5. Understand the arrangement and roles of transverse tubules,
sarcoplasmic reticulum, mitochondria, and contractile filaments in the
process of contraction
6. Understand the locations and roles of intercellular junctions in muscle
7. Understand the response of muscle to injury and the regenerative
capacity of the various types of muscle.
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Keywords
Slides
A. Types of Muscle
1. Striated
a. Skeletal
b. Cardiac
V.
Keywords
Learning Objectives
2. Smooth
B. Muscle Development (Skeletal)
Summary
A-band
Cardiac muscle
Endomysium
Epimysium
Fascicles
I-band
Intercalated disc
Muscle fiber
Myoblast
Myocardium
Myocytes
Myofibrils
Myotube
Perimysium
Sarcoplasmic reticulum
Satellite cell
Skeletal muscle
Smooth muscle
Striated muscle
Striations
T tubule
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Slides
A. Types of Muscle
1. Striated
a. Skeletal
b. Cardiac
V.
2. Smooth
B. Muscle Development (Skeletal)
Summary
Slide 7: Larynx, Trichrome
look here to see
skeletal muscle in
longitudinal-section
look here to see
skeletal muscle in
cross-section
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Learning Objectives
Keywords
Slides
A. Types of Muscle
1. Striated
a. Skeletal
b. Cardiac
V.
Slide 7: Larynx, Trichrome
Introduction
2. Smooth
B. Muscle Development (Skeletal)
endomysium
perimysium
Summary
individual skeletal
muscle fibers
(i.e., cells) seen in
cross-section
epimysium
fascicle
in skeletal muscle, endomysium is a delicate layer of reticular CT surrounding individual muscle fibers (cells);
perimysium is thicker connective tissue surrounding a group of fibers to form a bundle or fascicle; epimysium
is a sheath of dense connective tissue surrounding a collection of fascicles that constitute an entire muscle
the endo-, peri-, epi- prefixes for surrounding layers of connective tissue will be seen again for other structures, such
as the layers of CT surrounding peripheral nerves, so it is important to be familiar with their meaning and usage
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Slides
A. Types of Muscle
1. Striated
a. Skeletal
b. Cardiac
V.
2. Smooth
Slide 70: Tongue, H&E
surface of tongue;
what specific type
of tissue is this?
B. Muscle Development (Skeletal)
Summary
skeletal muscle
skeletal muscle (or visceral striated muscle, as seen in the tongue) is generally responsible for voluntary
movement within the body, mainly of the skeleton but also other structures such as the eyes and upper
esophagus for swallowing; it is composed of long multinucleated cells called muscle fibers which generally
extend the entire length of a muscle from tendon to tendon (up to 2ft long in the sartorius muscle in the thigh)
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Slides
A. Types of Muscle
1. Striated
a. Skeletal
b. Cardiac
V.
2. Smooth
B. Muscle Development (Skeletal)
Slide 70: Tongue, H&E
skeletal muscle
in longitudinal-section
Summary
skeletal muscle
in cross-section
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Slides
A. Types of Muscle
Slide 70: Tongue, H&E
1. Striated
notice that the nuclei of the
skeletal muscle fibers
have been displaced to the
periphery of the fiber/cell
by all the myofibrils filling
the cell
a. Skeletal
b. Cardiac
V.
2. Smooth
B. Muscle Development (Skeletal)
Summary
endomysium
surrounds individual
muscle fibers
perimysium surrounds the entire muscle fascicle
(composed of multiple muscle fibers/cells)
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Slides
A. Types of Muscle
1. Striated
a. Skeletal
b. Cardiac
V.
2. Smooth
B. Muscle Development (Skeletal)
Summary
Slide 8: Tongue, Trichrome
skeletal muscle
in longitudinal-section
skeletal muscle fiber
in cross-section
fibroblast of the
endomysium CT
nucleus of a muscle fiber
displaced to the periphery,
directly under the sarcolemma
skeletal muscle
in longitudinal-section
numerous capillaries can be seen in the
endomysium between the muscle fibers
using the know size of an RBC, estimate
the diameter of an adjacent muscle fiber
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Slides
A. Types of Muscle
1. Striated
a. Skeletal
b. Cardiac
V.
2. Smooth
B. Muscle Development (Skeletal)
Summary
Slide 17 (464): Skeletal Muscle, H&E
a few nuclei of fibroblasts,
forming the endomysium
or perimysium, may be
seen but can be difficult to
identify; the nuclei of
endothelial cells of
capillaries can also be seen
nuclei of skeletal muscle
fibers are displaced to the
periphery of the cells directly
beneath the sarcolemma
cross-striations (fine lines) are the alternating dark and light bands formed by the arrangement of the
myofilaments of the sarcomere (best seen in electron micrographs); the dark bands are the A-bands
(overlapping actin and myosin filaments) and the light bands are the I-bands (actin filaments); the visible
striations are the reason both skeletal and cardiac muscle are classified as striated muscle
Lab 9 – Muscle Tissue
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II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Slides
A. Types of Muscle
Slide 139: Heart, H&E
1. Striated
a. Skeletal
b. Cardiac
V.
2. Smooth
B. Muscle Development (Skeletal)
Summary
cardiac muscle is striated muscle, like skeletal muscle; however, it is localized to the walls of the heart and is
distinguishable by: (1) the branching of its muscle fibers; (2) a single nucleus per cell, generally round and
found near the center of the cell; and (3) the presence of intercalated discs between cells, so that the fibers
are actually many cells linked end-to-end, unlike the fibers of skeletal muscle which are a single
multinucleated cell
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Learning Objectives
Keywords
Slides
A. Types of Muscle
1. Striated
a. Skeletal
b. Cardiac
V.
Slide 139: Heart, H&E
Introduction
2. Smooth
B. Muscle Development (Skeletal)
Summary
what is this
“wear and tear”
pigment found
near the nuclei
in cardiac fibers?
“branching” of fibers
is characteristic of
cardiac muscle
round, centralized
nucleus of cardiac
muscle is distinct from
the multinucleated
peripheral, elongated
nuclei of skeletal muscle
cross-striations
(thin, faint lines)
intercalated disc
(thick, dark lines)
myofibrils
(parallel to fiber direction)
intercalated discs are highly specialized cell-to-cell adhesion junctions found in cardiac muscle; they
physically bind cells together to create long muscle fibers, so the force of contraction is transmitted between
the cells; they also promote the spread of action potentials from cell to cell via gap junctions
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Slides
A. Types of Muscle
1. Striated
a. Skeletal
b. Cardiac
V.
2. Smooth
B. Muscle Development (Skeletal)
Slide 66: Esophagus, H&E
lumen
Summary
look in the outer layer to
see smooth muscle in
cross-section
look in the inner layer to
see smooth muscle in
longitudinal-section
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Slides
A. Types of Muscle
1. Striated
a. Skeletal
b. Cardiac
V.
Slide 66: Esophagus, H&E
2. Smooth
B. Muscle Development (Skeletal)
Summary
elongated, centrallylocated nucleus of
smooth muscle fiber
seen longitudinally
smooth muscle fibers are long and tapered at both ends, generally ranging in length from 20-200µm; there are
no striations (hence, “smooth”) because the actin and myosin filaments do not show the same degree and kind
of organization as seen in striated muscle (skeletal and cardiac); like in cardiac muscle, there is a single, central
nucleus for each cell; however, in smooth muscle the nucleus conforms to the cell shape, unlike the typically
round nucleus of cardiac fibers; it is under involuntary control and is capable of slow, sustained contractions
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Slides
A. Types of Muscle
1. Striated
a. Skeletal
b. Cardiac
V.
2. Smooth
B. Muscle Development (Skeletal)
Summary
Slide 66: Esophagus, H&E
skeletal muscle
fiber
(cross-section)
smooth muscle
fiber
(cross-section)
the upper 1/3 of the esophagus is under voluntary control so has skeletal muscle (voluntary muscle); the
lower 2/3 is under involuntary control so has smooth muscle (visceral muscle); on this slide, from the
middle portion of the esophagus, the transition between the two muscle types can be seen
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Slides
A. Types of Muscle
1. Striated
Slide 66: Esophagus, H&E
cross-section
a. Skeletal
b. Cardiac
V.
longitudinal
2. Smooth
B. Muscle Development (Skeletal)
Summary
capillary
capillary
unlike skeletal muscle, smooth muscle makes its own surrounding CT, so fibroblasts are much more rare;
however, scattered throughout the tissue, the nuclei of endothelial cells (simple squamous epithelium)
may be seen lining capillaries
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Slides
A. Types of Muscle
Slide 21: Ileum, Trichrome
Slide 37: Ileum, H&E
1. Striated
a. Skeletal
b. Cardiac
V.
2. Smooth
B. Muscle Development (Skeletal)
Summary
smooth muscle
in longitudinal-section
smooth muscle
in cross-section
smooth muscle
in longitudinal-section
smooth muscle
in cross-section
the entire GI tract, including the esophagus seen previously and the ileum – part of the small intestine – seen
above, contains a surrounding layer of smooth muscle called the muscularis; the muscularis is principally
composed of two layers of smooth muscle, with fibers in one layer having perpendicular orientation to the
adjacent layer; contraction of these layers allows the GI “tube” to both shorten in length and reduce the
diameter of its lumen
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Slides
A. Types of Muscle
Slide 159: Fetal Mouse Head
Slide Overview
developing brain
1. Striated
a. Skeletal
b. Cardiac
V.
2. Smooth
cartilaginous
nasal septum
B. Muscle Development (Skeletal)
Summary
look in the oral cavity at the
tongue to see developing
skeletal muscle
vertebrae
endochondral
ossification
newly-forming woven
bone of the mandible
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Slides
A. Types of Muscle
Slide 159: Fetal Mouse Head
1. Striated
a. Skeletal
b. Cardiac
V.
2. Smooth
B. Muscle Development (Skeletal)
Summary
myoblasts are the
skeletal muscle
precursor cells found
interspersed amongst
the myotubes
myotubes
during embryonic development, mesenchymal myoblast cells fuse to form multinucleated myotubes,
which will later further differentiate to form mature, striated skeletal muscle fibers
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Slide 40a (464): Fetal Tongue, H&E
Keywords
Slides
A. Types of Muscle
1. Striated
Slide 12a (464): Guinea Pig Head
a. Skeletal
b. Cardiac
V.
2. Smooth
B. Muscle Development (Skeletal)
Summary
the development of skeletal muscle in the
tongue by the fusion of myoblasts into
myotubes can be seen on several other slides
Slide 130: Fetal Skull
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Common Confusion:
Smooth Muscle vs. Dense Regular CT
Smooth muscle: muscle found in the walls of vessels and
organs, so also known as visceral muscle; it lacks the striated
appearance of skeletal and cardiac muscle
Slides
A. Types of Muscle
1. Striated
a. Skeletal
b. Cardiac
V.
2. Smooth
B. Muscle Development (Skeletal)
Summary
Smooth muscle
Look for: (1) long, tapered cells with a central nucleus
conforming to the cell’s shape; (2) nuclei are intracellular,
and there are rarely fibroblasts; (3) nuclei appear somewhat
clustered and aligned, as the thickest part of one cell stacks
against the thinnest part of adjacent cell; (4) nuclei may
appear ‘wavy’ if cells are contracted; (5) more abundant
vasculature or other tissue types may be visible
Dense regular CT: connective tissue proper with thick
bundles of collagen arranged in parallel to provide maximal
tensile strength along one axis; it is found in tendons,
ligaments, capsules, and aponeuroses
Dense regular CT
Look for: (1) eosinophilic collagen is regular and densely
packed; (2) nuclei are fewer and often highly flattened but
can have more varied appearance; (3) nuclei located between
collagen bundles (i.e., they don’t appear to be ‘intracellular’);
(4) vasculature is usually poor and sparse
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Common Confusion:
Smooth Muscle vs. Cardiac Muscle in Cross-Section
Smooth muscle: muscle found in the walls of vessels and
organs, so is also known as visceral muscle; it lacks the
striated appearance of skeletal and cardiac muscle
Slides
A. Types of Muscle
Look for: (1) fusiform shape of cells gives the appearance of
cells of differing widths; (2) higher density of nuclei due to
packing of cells, but nuclei often appear in clusters rather
than uniformly distributed; (3) tight packing makes
discernment of individual cells often difficult
1. Striated
a. Skeletal
b. Cardiac
V.
2. Smooth
B. Muscle Development (Skeletal)
Summary
Smooth muscle
Cardiac muscle: striated muscle found in the walls of the
heart; in cross-section it is quickly distinguished from
skeletal muscle by the location of the nuclei
Look for: (1) generally abundant endomysium with
interspersed fibroblasts and capillaries; (2) myofibrils fill the
muscle fibers; (3) lipofuscin granules may be seen
Cardiac muscle
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
IUSM – 2016
Introduction
Learning Objectives
Keywords
Slides
A. Types of Muscle
Summary
1.
1. Striated
a.
a. Skeletal
b. Cardiac
V.
Striated muscle includes both skeletal muscle and cardiac muscle; it is identified by
the presence of a distinct cross-striation pattern of alternating lighter-staining Ibands and darker-staining A-bands.
2. Smooth
b.
B. Muscle Development (Skeletal)
Summary
2.
3.
Skeletal muscle fibers (under voluntary control) are long, cylindrical
multinucleated cells with peripherally-located nuclei; the fibers are formed by
the fusion of numerous mesenchymal myoblast cells during development.
Cardiac muscle, found within the heart, differs from skeletal muscle by having
only one or two centrally-located round nuclei, branching fibers, and
intercalated discs (join cells end-to-end).
Smooth muscle is muscle found in the walls of vessels and organs, so is also known
as visceral muscle; it is called smooth because it lacks the sarcomere organization and
striated appearance of skeletal and cardiac muscle; it is under involuntary control and
is capable of slow, sustained contractions.
Entire skeletal muscles are surrounded by dense connective tissue called epimysium;
from the epimysium, less-dense and thinner perimysium extends inward and divides
the muscle into fascicles (bundles of muscle fibers); a thin layer of reticular connective
tissue, called endomysium, surrounds individual muscle fibers. Within all the layers
of the connective tissue there are blood vessels, nerves, and lymphatics.
Lab 9 – Muscle Tissue
I.
II.
III.
IV.
Introduction
Learning Objectives
Keywords
Slides
A. Types of Muscle
1. Striated
a. Skeletal
b. Cardiac
V.
Comparison of Different Muscle Types
IUSM – 2016
2. Smooth
B. Muscle Development (Skeletal)
Summary
Skeletal Muscle
Locations
Function
Striated?
Multinucleated?
Location of nuclei
Cell shape
Branching?
Cell junctions
Connective tissue
layers
Regeneration
mechanism
Sketch of fibers
Cardiac Muscle
Smooth Muscle