The document provides an introduction to the muscular system, including: - The three types of muscle tissue: skeletal, smooth, and cardiac. - Skeletal muscle is voluntary and allows movement, while smooth and cardiac muscles are involuntary. - Muscles are named based on size, shape, direction, location, number of origins, and action. - The four major muscle groups are those of the head/neck, trunk, upper extremities, and lower extremities. - Key functions of muscles include motion, posture, joint stability, and heat production.

1. Introduction to
the Muscular
System

2. Introduction to the Muscular
System

3. Introduction to
the Muscular
System

4. Muscle Types
The 3 types of muscle tissue are cardiac, smooth, and skeletal.

5. Muscle Types
Skeletal Muscle,
• Skeletal muscle, also called voluntary muscle, in vertebrates, most common of the three types of muscle in the body.
Skeletal muscles are attached to bones by tendons, and they produce all the movements of body parts in relation to
each other.
• skeletal muscle is its ability to contract and cause movement. Skeletal muscles act not only to produce movement
but also to stop movement, such as resisting gravity to maintain posture.
• Skeletal muscles also protect internal organs (particularly abdominal and pelvic organs) by acting as an external
barrier or shield to external trauma and by supporting the weight of the organs.
• cover the skeletal framework and are attached directly attached to the bones via tendons. These muscles carry out
movements which can be controlled by your thoughts and are known as voluntary muscles and they are what ache
after strenuous exercise.

6. Muscle Types
Smooth Muscle,
• Smooth muscle, found in the walls of the hollow internal organs such as blood vessels,
the gastrointestinal tract, bladder, and uterus, is under control of the autonomic
nervous system. Smooth muscle cannot be controlled consciously and thus acts
involuntarily. The non-striated (smooth) muscle cell is spindle-shaped and has one
central nucleus. Smooth muscle contracts slowly and rhythmically.
• Smooth muscle fibers are in walls of hollow visceral organs, except the heart, appear
spindle-shaped, and are also under involuntary control.

7. Muscle Types
Cardiac Muscle,
Cardiac muscle, found in the walls of the heart, is also under control of the autonomic
nervous system. The cardiac muscle cell has one central nucleus, like smooth muscle,
but it also is striated, like skeletal muscle. The cardiac muscle cell is rectangular in shape.
The contraction of cardiac muscle is involuntary, strong, and rhythmical.

8. Muscle Groups
There are more than 600 muscles in the body, which together account for about 40 percent of a
person's weight. Most skeletal muscles have names that describe some feature of the muscle. Often
several criteria are combined into one name. The following are some terms relating to muscle features
that are used in naming muscles.
Size: vastus (huge); maximus (large); longus (long); minimus (small); brevis (short).
Shape: deltoid (triangular); rhomboid (like a rhombus with equal and parallel sides); latissimus (wide);
teres (round); trapezius (like a trapezoid, a four-sided figure with two sides parallel).
Direction of fibers: rectus (straight); transverse (across); oblique (diagonally); orbicularis (circular).
Location: pectoralis (chest); gluteus (buttock or rump); brachii (arm); supra- (above); infra- (below);
sub- (under or beneath); lateralis (lateral).
Number of origins: biceps (two heads); triceps (three heads); quadriceps (four heads).
Origin and insertion: sternocleidomastoideus (origin on the sternum and clavicle, insertion on the
mastoid process); brachioradialis (origin on the brachium or arm, insertion on the radius).
Action: abductor (to abduct a structure); adductor (to adduct a structure); flexor (to flex a structure);
extensor (to extend a structure); levator (to lift or elevate a structure); masseter (a chewer).

9. Muscle Groups

10. Muscles of the Head and
Neck
Humans have well-developed muscles in the face that permit a large variety of facial expressions.

11. Muscles of the Trunk
The muscles of the trunk include those that move the vertebral column, the muscles that form the thoracic
and abdominal walls, and those that cover the pelvic outlet.

12. Muscles of the Upper
Extremity
The muscles of the upper extremity include those that attach the scapula to the thorax and generally move
the scapula, those that attach the humerus to the scapula and generally move the arm, and those that are
in the arm or forearm that move the forearm, wrist, and hand.

13. Muscles of the Lower
Extremity
When a medical professional refers to your lower extremity, they’re typically referring to everything
between your hip to your toes.

14. Function of Muscular
System
.
•Motion: The main function of muscles is motion, for example in
conjunction with the bones for walking. Muscles may work alone e.g. the
diaphragm for breathing, and the heart for circulating blood.
•Stabilizing: Muscles help maintain body positions.
•Thermogenesis: Muscles produce body heat.
•Support: Muscles support soft tissue, such as the abdominal wall and
pelvic floor.
•Guard Entrance and Exits: Muscles are also involved in swallowing,
defecation, and urination (sphincter muscles).

15. Characteristics of Muscular
System
.
.
•Irritability: (excitability) Muscles receive and respond to
stimulation.
•Contractibility: Allows muscles to change shape to become
shorter and thicker.
•Extendibility: Living muscle cells can be stretched and extended;
longer and thinner.
•Elasticity: Once the stretching force is removed, a living muscle
cell retains its original shape

16. Review: Introduction to the Muscular System
Here is what we have learned from Introduction to the Muscular System:
• One of the most predominant characteristics of skeletal muscle tissue is its contractility
and nearly all movement in the body is the result of muscle contraction.
• Four functions of muscle contraction are movement, posture, joint stability, and heat
production.
• Three types of muscle are skeletal, smooth, and cardiac.
• Each muscle fiber is surrounded by endomysium. The fibers are collected into bundles
covered by perimysium. Many bundles, or fasciculi, are wrapped together by the
epimysium to form a whole muscle.
• Muscles are attached to bones by tendons.
• Muscle features such as size, shape, direction of fibers, location, number of origins, origin
and insertion, and action are often used in naming muscles.
• Four major muscle groups of the body include:
• Muscles of the head and neck;
• Muscles of the trunk;
• Muscles of the upper extremity; and
• Muscles of the lower extremity.

17. Special attention:
•If you activate the muscle in its lengthened state, then it gradually stretches further then relaxes more; eventually
becoming stronger. So, activate muscles that are stretched in a pose.
•When a muscle is stretched long enough, then the muscle relaxes eventually. So always hold the posture longer
[at least 15 seconds].
•If you activate or tense one muscle, the surrounding group of muscles is also fired and eventually leads to better
strength and stability.
•Counter poses: In yoga you can use counter poses to successfully create balance. Vinyasas are counter poses
[Upward dog/ downward dog]. It is important to use counter poses too in your classes since they balance and
reset the muscles. For example, forward bends followed by back bends, side bends by doing on both sides,
internal rotation by external rotation.
•As you move from one pose to the next during a yoga session, try to enter and exit the pose with grace and
elegance. A smoother, gentler, and more controlled movement strengthens the body, quiets the mind induces
relaxation and control.
•Creating internal heat within your body gives you more flexibility and helps your body release toxins.
•Active stretching is where you assume a position and hold it by using the relative muscle groups. It builds up
strength in muscles involved.
•Passive stretching is where you assume and hold a pose with the help or support of parts of your body, partner,
blocks, or other assistance. It helps with cooling down and reduces post-workout soreness and tension.