• Muscle is one of the four primary tissue types.

• Skeletal muscles are organs that include all four basic tissue types.

- Consists primarily of skeletal muscle cells.

• More than 700 skeletal muscles are found in the body.

• Contractile organs that are directly or indirectly attached to the skeleton.

- Produces skeltal movement

- Maintains posture and body position

- Supports soft tissues

- Regulates entering and existing of material

- Maintains body temperature

- muscle contractions pull on

tendons and move the bones of the skeleton

• Constant muscular contraction of specific muscles

      - Balancing the weight of the body while walking

 - Holding the head in positions while reading

• Muscle contractions require energy, and whenever energy is used in body, some of it is converted to heat

- Heat lost by contracting muscles keeps our body

temperature in a normal range

-Epimysium

-Perimysium

-Endomysium

• Outer layer that surrounds the entire muscle

- Separates the muscle from the surrounding tissues and organs and is connected to the deep fascia of the connective tissue framework

- Dense irregular connective tissue

• Divides the muscles into a series of internal

compartments each containing a bundle of muscle fibers

called a fascicle.

- Contains collagen and elastic fibers.

• Surrounds each skeletal muscle fiber and binds it to its neighbor

        - Supports capillaries that supply the individual fibers

          - Consists of a delicate network of reticular fibers

     - Scattered myosatellite cells lie between the endomysium and the muscle fibers

                          - Function in the repair of damaged muscle fibers

• The connective tissue fibers of the endomysium and perimysium are interwoven.

• Collagen fibers of the epimysium, perimysium and

endomysium converge to form the fibrous tendon (dense

regular connective tissue) that attaches muscle to bone, skin or another muscle.

• Tendon fibers are interwoven into the periosteum and matrix of the associated bone. Bone is extremely strong so that any contraction of a muscle will exert a pull on the attached bone

• Skeletal muscles are called voluntary because their

contractions can be consciously controlled.

• The connective tissues contain the nerves and blood vessels that supply the muscle fibers.

• Nerves penetrate the epimysium and branch through the

perimysium and enter the endomysium to innervate individual muscle fibers.

• Somatic nervous system.

•Where the chemical communication between the synaptic

terminal of a neuron and a skeletal muscle fiber occurs

• Each muscle fiber has one neuromuscular junction, usually located midway along its length

1)  Whole muscle

2)  Muscle fascicles

3)  Muscle fiber (cell)

4)  Myofibril

5)  Myofilaments

             - Actin-thin filament

                 - Myosin- thick filament

• Muscle fibers within a skeletal muscle form bundles called fascicles

• The muscle fibers of each fascicle lie parallel to one another, but the organization of the fascicles in the skeletal muscle can vary.

• There are four different patterns of fascicle arrangement:

- Parallel

- Convergent

- Pennate

- Circular

• Fascicles are parallel to the long axis of the muscle

• Most skeletal muscles in the body are parallel muscles

• These muscles have a central body (belly)

•When this muscle contracts, it gets shorter and the body increases in diameter

• Ex- biceps brachii

• Fibers are based over a broad.

area, but all the fibers come together at a common attachment site.

• Muscle fibers often spread, out like a fan, with a tendon at the tip.

• Have versatility.?

• Use of different portions of the same muscle can flex, extend or abduct an arm.

•When they all contract at once they do not pull as hard on the tendon as a parallel muscle of the same size.

• Muscle fibers on opposite sides of the tendon pull in

different directions rather than working together.

• Ex- pectoralis major muscle.

- the direction of pull can be changed by

stimulating only one group of muscle cells at a time.

• One or more tendons runs through the body of the muscle.

• Fascicles form an oblique angle to the tendon.

• Because these muscles pull at an angle, contracting pennate muscles do not move their tendons as far as parallel muscles do.

• Contain more muscle fibers than a parallel muscle and as a result, generate more tension than that of a parallel muscle of the same size.

• Fibers are concentrically arranged an opening or recess.

•When the muscle contract, the diameter of the opening decreases.

• Guards the entrances and exits of internal passageways such as the digestive and urinary tracts.

• Ex- Orbicularis oris.

Origin

Insertion

Action

• The triceps inserts on the olecranon process and originates closer to the shoulder.

• The deltoid originates on the scapular spine and inserts on the deltoid tuberosity of the humerus.

- Prime movers (agonists

- Synergists

-Antagonist

• Assist the prime mover in performing the action.

- May provide additional pull near the insertion or stabilize the point of origin.

- Ex- the teres major is a synergist to the latissimus dorsi.

• Actions oppose that of the agonist.

- Ex- biceps brachii (flexion), triceps brachii (extension).

Naming of skeletal muscule?

Like Shape? Example?

Like Location? Example?

• Shapes

• Trapezius- trapezoid

• Orbicularis- circle

• Deltoid- triangle

• Location

• Externus or superficialis- muscles visible at the body surface

• Internus or profundus- muscles lying beneath the superficial muscles

Shape 

location

Attachment

Orientation of fibers

Specific structural features

function

•origin and insertion

- Stylohyoid

- Sternocleidomastoid

originates on the styloid process of the temporal

bone and inserts on the hyoid bone

originates on the sternum and clavicle

and inserts on the mastoid process of the temporal bone

Rectus

Transverse

Oblique

perpendicular to the midline (transverse

abdominis)

Biceps

Triceps

Quadriceps

• Action

-Flexor

-Ectensor

Longus

Brevis

Major

Maximus

Minor

Minimus