1. Chapter 10 Muscular Tissue
Lecture slides prepared by Curtis DeFriez, Weber State University

2. Functions of Muscular Tissue
Like nervous tissue, muscles are excitable or "irritable”
they have the ability to respond to a stimulus
Unlike nerves, however, muscles are also:
Contractible (they can shorten
in length)
Extensible (they can extend or
stretch)
Elastic (they can return to their
original shape)

3. Functions of Muscular Tissue
Muscle makes up a large percentage of the body’s weight
Their main functions are to:
Create motion – muscles work with nerves, bones, and joints to produce body movements
Stabilize body positions and maintain posture
Store substances within the body using sphincters
Move substances by peristaltic contractions
Generate heat through thermogenesis

4. Three Types of Muscular Tissue
Location
Function
Appearance
Control
Skeletal
skeleton
movement, heat, posture
striated, multi-nucleated (eccentric), fibers parallel
voluntary
Cardiac
heart
pump blood continuously
striated, one central nucleus
involuntary
Visceral
(smooth muscle)
G.I. tract, uterus, eye, blood vessels
Peristalsis, blood pressure, pupil size, erects hairs
no striations, one central nucleus

5. Three Types of Muscular Tissue
(a) Skeletal muscle
(b) Cardiac muscle
(c) Visceral smooth muscle

6. Skeletal Muscle Location Function Appearance Control Skeletal skeleton
movement, heat, posture
striated, multi-nucleated (eccentric), fibers parallel
voluntary
Cardiac
heart
pump blood continuously
striated, one central nucleus
involuntary
Visceral
(smooth muscle)
G.I. tract, uterus, eye, blood vessels
Peristalsis, blood pressure, pupil size, erects hairs
no striations, one central nucleus

7. Skeletal Muscle
All muscle start as these spindly shaped cells from myoblasts – skeletal muscle cells fuse to form large fibers…
Satellite cells are small mononuclear progenitor cells with virtually no cytoplasm found in mature muscle. They are found sandwiched between the basement membrane and sarcolemma (cell membrane) of individual muscle fibres, and can be difficult to distinguish from the sub-sarcolemmal nuclei of the fibres. Satellite cells are able to differentiate and fuse to augment existing muscle fibres and to form new fibres. These cells represent the oldest known adult stem cell niche, and are involved in the normal growth of muscle, as well as regeneration following injury or disease.

8. A single skeletal muscle fiber
Skeletal muscle fibers are very long “cells” - next to neurons (which can be over a meter long),
perhaps the longest in the body
The Sartorious muscle contains
single fibers that are at least
30 cm long
It’s difficult to find the sartorius muscle in some people (cadavers)
A single skeletal muscle fiber

9. Skeletal Muscle
The terminal processes of a motor neuron in close proximity to the sarcolemma of a skeletal muscle fiber
Motor neuron
Sarcolemma

10. Organization of Muscle Tissue
The epimysium, perimysium, and
endomysium all are continuous with
the connective tissues that form
tendons and ligaments (attach
skeletal muscle to bone) and muscle
fascia (connect muscles to other
muscles to form groups of muscles)

11. Organization of Muscle Tissue
Epimysium
Perimysium
These next few graphics show connective tissue elements associated with skeletal muscle: Starting with whole muscles and working our way down to fascicles and individual muscle cells (fibers).
Organization of a single muscle belly

12. Organization of Muscle Tissue
Organization of a fasciculus

13. Organization of Muscle Tissue
Organization of a muscle fiber

14. Organization of Muscle Tissue
A muscle, a fasciculus, and a fiber all visualized

15. Organization of Muscle Tissue
In groups of muscles the epimysium continues to become thicker, forming fascia which covers many muscles
This graphic shows the fascia lata enveloping the entire group of quadriceps and hamstring muscles in the thing

16. Organization of Muscle Tissue
Many large muscle groups are encased in both a superficial
and a deep fascia
Real Anatomy, John Wiley and Sons