1. The Muscular System

2. Muscle tissue overview
All muscle cells are elongated, thus, all muscle cells, regardless of type, are called muscle fibers
The ability of muscle to shorten or contract depends on 2 types of myofilaments
Prefix:
myo/mys: muscle
Sarco: flesh

3. Regulation of Contraction: Contraction Speed/Rhythmic:
Muscle Types
Muscle type:
skeletal muscle
cardiac muscle
smooth muscle
walls of hollow organs;
Body location:
attached to bone;
walls of heart;
single, very long
cylindrical, multi-
nucleate, striations;
branching chains,
uninucleate, striations;
Single, spindles,
uninucleate, no
striations;
Cell Shape:
involuntary, ner-
vous system
controls, hormones,
chemicals, stretch;
involuntary, ner-
vous system
controls, hormones;
Regulation of Contraction:
voluntary, nervous
system controls;
Contraction Speed/Rhythmic:
Slow to fast/no;
Slow/yes;
Very slow/some

4. Skeletal Muscle
Key words: Skeletal, Striated, Voluntary

5. Skeletal Muscle
Skeletal muscle fibers: are packed into the organs called skeletal muscles that attach to the body’s skeleton
Skeletal muscle fibers are cigar-shaped, multinucleate cells, and are the largest of the muscle fiber types
It is also known as striated muscle because its fibers appear to be striped
It is also known as voluntary muscle because it is the only muscle type subject to conscious control
Skeletal muscle tissue can contract rapidly and with great force, but it tires easily and must rest after short periods of activity

6. Connective tissue wrapping
Each muscle fiber is enclosed in a delicate connective tissue sheath called an endomysium
A bundle of muscle fibers called a fascicle are surrounded by a connective tissue called the perimysium
A bundle of fascicles are surrounded by a connective tissue called the epimysium

7. Tendons The epimysia blend into the strong, cordlike tendons
Tendon connects muscle to bone
Tendons provide durability and conserve space

8. Key words: Cardiac, striated, uninucleate, involuntary, heart
Cardiac Muscles
Key words: Cardiac, striated, uninucleate, involuntary, heart

9. Cardiac Muscle Is found only in the heart
Cardiac muscle is like skeletal muscle in that it is striated and like smooth muscle in that it is involuntary and cannot be consciously controlled by most of us
Cardiac muscle fibers are branching cells joined by special junctions called intercalated disks

10. Cardiac Muscle
The cardiac muscle is cushioned by small amounts of soft connective tissue and arranged in spiral or figure 8 bundles
Cardiac muscle usually contracts at a fairly steady rate set by the heart’s pacemaker, but can also be stimulated by the nervous system

11. Smooth Muscle
Key words: smooth, visceral, involuntary, uninucleate, non-striated

12. Smooth Muscle Smooth muscle has no striations and is involuntary
Found in the walls of hollow visceral organs such as the stomach, urinary bladder etc.

13. Smooth Muscle Smooth muscle cells are arranged in 2 layers:
One layer runs circularly
The other running longitudinally
The two layers alternately contract and relax, and this changes the size and shape of the organ, resulting in the movement of food, wastes, etc.

14. 4 Muscle Functions producing movement maintaining posture
stabilizing joints
generating heat
walking;
swimming;
move eyes;
Smile 
Frown 
move fluid;
move food.
allow you to
stand up straight
against the
force of
gravity.
help reinforce
bones that do
not articulate
well with the
skeleton;
Ex.: shoulder
ATP used to
cause muscles
to contract;
ATP energy is
lost as heat;
This helps
maintain body
temperature.