1. MUSCULAR SYSTEM OVERVEIW “the power system”
Nearly half our weight comes from
muscle tissue.
There are 650 different muscles in the
human body.
Muscles give us form and shape.
Muscles produce most of our body heat.

2. MUSCLE TYPES
SKELETAL
SMOOTH
TYPES OF MUSCLES
CARDIAC

3. Skeletal Muscle
Attached to bone
Striated (striped) appearance
VOLUNTARY
Multinucleated muscle cell bundles (muscle cells = muscle fibers)
SARCOLEMMA = cell membrane
Contract quickly, fatigue easily, can’t maintain contraction for long period of time

4. Smooth Muscle
Visceral (organ) muscle
Found in walls of digestive system, uterus and blood vessels
Cells small and spindle-shaped
INVOLUNTARY
Controlled by autonomic nervous system
Act slowly, do not tire easily, can remain contracted for long time

5. Cardiac Muscle
Found only in the heart
Striated and branched
Involuntary
Cells are fused – when one contracts, they all contract

6. Four important roles in body:
MAIN FUNCTIONS
Four important roles in body:
1. Responsible for all body movement.
2. Responsible for body form and shape
(posture)
3. Stabilize joints
4. Responsible for body heat and maintaining
body temperature.

7. SKELETAL MUSCLE ACTIVITY
Stimulation and Contraction of Skeletal Muscle Cells
EXCITEABILITY (IRRITABILITY) – the ability to respond to certain stimuli by producing impulses.
CONTRACTIBILITY – the ability of a muscle to reduce the distance between the parts of its contents or the space it surrounds.

8. SKELETAL MUSCLE ACTIVITY
MOTOR UNIT – a motor neuron plus all the muscle fibers it stimulates.
NEUROMUSCULAR JUNCTION – the junction between the motor neuron’s fiber which transmits the impulse – and the muscle cell membrane.
ACETYLCHOLINE – chemical neurotransmitter, diffuses across the synaptic cleft (carries impulse across synaptic cleft)
MUSCLE FATIGUE – caused by the accumulation of lactic acid in the muscles.
OXYGEN DEBT – after exercise, the amount of oxygen needed by the muscle to change lactic acid back to glucose.
MUSCLE TONE - When muscles are slightly contracted and ready to pull.
DIAPHRAGM – Dome-shaped muscle that separates the abdominal and thoracic cavities, aids in breathing

9. MUSCLE CONTRACTIONS Muscle Tone
In order to function, muscles should always be slightly contracted and ready to pull.
Muscle contractions may be isotonic or isometric.
ISOTONIC CONTRACTION
When muscles contract and shorten. (Walk, talk, etc.)
ISOMETRIC CONTRACTION
When the tension in a muscle increases
but the muscle does not shorten.
(exercises such as tensing the abdominal muscles.)

10. MUSCULAR SYSTEM MUSCLE MOVEMENT Muscles move bones by pulling on them.
“the power system”
MUSCLE MOVEMENT
Muscles move bones by pulling on them.
As a muscle contracts, it pulls the insertion bone closer to the origin bone. Movement occurs at the joint between the origin and the insertion.
2. Groups of muscles usually contract to produce a single movement.
3. When the antagonist muscles contract, they produce a movement opposite to that of the prime movers.

11. Anterior Surface of Body
Gross Anatomy of Skeletal Muscles
Anterior Surface of Body
Frontalis
Orbicularis oris
Sternocleidomastoids
Deltoid
Pectoralis major
Biceps brachii
Intercostals muscles
Rectus abdominus
External oblique
Sartorius
Quadriceps group

12. Gross Anatomy of Skeletal Muscles Posterior Surface of Body
Occipitallis
Trapezius
Deltoid
triceps brachii
Latissimus dorsi
Gluteus medius
Gluteus maximus
Hamstrings
Gastrocnemius
Soleus
Achilles tendon

13. Disorders and Related Terminology
ATROPHY – wasting away of muscle due to lack of use.
HYPERTROPHY – an increase in the size of the muscle cell.
STRAIN – tear in the muscle resulting from excessive use. Bleeding inside the muscle can result in pain and swelling. Ice packs will help stop bleeding and reduce swelling.
MUSCLE SPASM (cramp) – sustained contraction of the muscle, usually because of overuse.
MYALGIA – muscle pain
TENDONITIS – inflammation of a tendon