1. Allied Health Sciences I Melissa Lewis, RN
Muscular System
Allied Health Sciences I
Melissa Lewis, RN

2. Muscles ½ of our body weight comes from our muscles
Human body has 656 different muscles
Muscles give body form and shape
Muscles are also responsible for movement

3. 3 Types of Muscles 1. Skeletal 2. Smooth 3. Cardiac
These muscles can be described as striated (striped) , spindle-shaped, and non-striated.

4. Skeletal Muscles Attach to bones of skeleton Striped or striated
Voluntary muscles
Each muscle cell is multi-nucleated and known as a muscle fiber
The cell membrane of a muscle cell = sarcolemma
Cytoplasm of muscle cell = sarcoplasm

5. Smooth (visceral) Muscle
Small and spindle-shaped
Only have one nucleus
Non-striated
They are not attached to bones
They act slowly and do not tire easily
They remain contracted for a long time
Involuntary
They are controlled by the autonomic (automatic) nervous system

6. Smooth (visceral) Muscle cont…
They are found in the walls of stomach, intestines, uterus, & blood vessels
Their actions = helping food pass along uterine contractions, control of diameter of blood vessels

7. Cardiac Muscle Found only in the heart Striated Involuntary
Cardiac cells are joined in a continuous network
So, when one cell receives a signal to contract they all contract together to cause a heart beat
Normal heart rate is 72 beats/minute
Cardiac cells have to have continuous oxygen to function (no oxygen for 30 seconds = death)

8. Sphincter/dilator Muscles
Special circular muscles in the openings between the esophagus and stomach, and stomach and small intestine
Also found in anus, urethra, mouth
They open and close to control passage of substances

9. Principle Skeletal Muscles
Skeletal muscles are voluntary
Made up of all muscles that attach to and help the skeleton move
Make up lining of walls of oral, abdominal, and pelvic cavities
Control movement of eyeballs, eyelids, lips, tongue, and skin
Muscles are named by their location, size, direction, # of origins, location of origin & insertion, and action

10. Examples: Location: Frontalis – forehead
Size: Gluteous maximus – largest muscle in buttock
Number of origins – Biceps – 2-headed muscle on humerus
Location of origin/insertion – sternocleidomastoid – originates in sternum

11. Misc. Muscle Information
656 muscles in human body
327 antagonistic pairs
2 unpaired muscles
Orbicularis oris
Diaphragm
Muscular Regions
Head, neck, trunk & extremity

12. All Muscles have 4 things in common:
Contractibility – When a muscle contracts, it shortens causing a decrease in distance b/w parts
No other cell can do this
Excitability – To respond to certain stimuli by producing impulses
Both muscle and nervous cells can do this
Extensibility – Ability to be stretched
Elasticity – Ability to return to its original length when relaxed

13. Muscle Attachments & Functions:
Muscles have to be attached to bones to cause movement
Muscles only pull, they never push

14. Muscle Attachments & Functions cont…
1. Origin – part of the skeletal muscle that is attached to a fixed structure or bone (it moves the least during contraction)
2. Insertion – the other end of attachment , that is attached to movable part (it moves the most during contraction)
3. Belly – central body of muscle
4. Prime mover – muscles work in pairs, produces movement in a single direction

15. Muscle Attachments & Functions cont…
5. Antagonist – this is the second muscle that has an opposite pull from the prime mover
6. Synergists – group of muscles, which help steady a movement or stabilize joint activity
***Example of antagonist pair would be the biceps and the triceps (when the biceps is contracted, the triceps is relaxed)***

16. Sources of Energy and Heat
Muscles not only move our bodies, but they also produce heat.
Our body temp must be between 98.6 degrees F and 99.8 degrees F.
Muscle cells make adenosine triphosphate (ATP)
ATP is necessary for muscles to contract and make heat that body needs

17. Contraction of Skeletal Muscle
Two things that cause movement by muscles
1. Myoneural stimulation
2. Contraction of muscle proteins
***A nerve impulse initiates movement
5 steps to muscles movement (look in book 4 this)
1. Nerve Impulse
2. Axon
3. Acetylcholine
4. Synaptic cleft
5. Sarcolemma
For cell to return to a resting state, potassium and sodium ions diffuse back to their initial positions outside the cell

18. Muscle Tone and Fatigue
Muscle tone – muscles are always slightly contracted. Gives muscle tone. Muscle tone maintained through adequate nutrition and regular exercise.
Atrophy – disuse of muscles thus they shrink or atrophy
Hypertrophy – over-exercise, muscles become enlarged or hypertrophied
Muscle fatigue – caused by build-up of lactic acid in muscles. Lactic acid is a waste product of muscle cells.

19. Exercise and Training
Exercise and training changes the size, structure and strength of a muscle.
Atrophy – muscles goes away
Hypertrophy – muscles get bigger
Proper training can improve:
Coordination
Respiratory and circulatory system
Rids excess fat
Joint movement
Strength can improve
Muscle size
Muscle coordination
Functioning of cortical brain region

20. Injury and overuse Sprain – Strain – Bursitis –
Ligaments either torn from attachments to bones or torn across. Rapid swelling and acute pain
Treatment = anti-inflammatory drugs
Strain –
Tear in muscle result of excessive use (tx = ice)
Bursitis –
these bursa sacs contain synovial fluid that serves as lube to prevent friction b/w tendon and bone. If sac is injured it can cause bursitis.

21. Injury and overuse cont…
Muscle spasm – a cramp (sustained contraction of the muscle)
Myalgia – muscle pain
Muscular dystrophy – group of diseases in which the muscle cells deteriorate
Myasthenia gravis – leads to progressive muscular weakness and paralysis, sometimes death (unknown cause)

22. Tendons Cords of connective tissue that attach the muscles to bone
Sometimes they are excessively stretched through exercise
They become unable to contract & return to their original place
Therefore, they are more susceptible to straining and tearing

23. Recreational Injuries
Tennis Elbow – also called lateral epicondylitis
Inflammed tendon that connects arm muscle to elbow
Treatment = pain relief, ice packs, surgery last resort

24. Recreational Injuries cont…
Shin splints – occur when there is injury to muscle tendon in front of shin
Usually occurs during jogging
One should wear supportive shoes
Rotator cuff disease – inflammation of group of tendons that fuse together and surround shoulder joint
Treatment = rest & physical therapy

25. Treatment
Massage – occasionally a HC professional may need to give a total body massage or a massage to specific body area
One must know which skeletal muscles are involved and proper way to massage area
Physiotherapy – treatment of disease/injury by physical means using light, heat, cold, water, electricity, massage, & exercise

26. Intramuscular Injections
Injections (shots) given directly into the muscle
Most common sites for intramuscular injections:
Deltoid muscle of upper arm
Vastus Lateralis (anterior thigh)
Gluteus medius (buttocks)

27. Major Muscles of Body MUSCLE LOCATION FUNCTION Sternocleid-omastoid
Side of neck
Turns & flexes head
Trapezius
Upper back & neck
Turns head, moves shoulder
Deltoid
Shoulder
Abducts arm

28. Major Muscles of Body MUSCLE LOCATION FUNCTION Biceps brachii
Upper arm
Flexes lower arm
Triceps brachii
Extends lower arm
Pectoralis major
Upper chest
Adducts upper arm

29. Major Muscles of Body MUSCLE LOCATION FUNCTION Intercostals
Between ribs
Moves ribs for breathing
Rectus abdominus
Ribs to pubis
Compresses abdomen
Latissimus dorsi
Spine around to chest
Extends & adducts upper arm

30. Major Muscles of Body MUSCLE LOCATION FUNCTION Gluteus maximus
Buttocks
Extends thigh
Sartorius
Front of thigh
Abducts
Quadriceps femoris
Extends leg

31. Major Muscles of Body MUSCLE LOCATION FUNCTION Tibialis anterior
Front of lower leg
Flexes & inverts foot
Gastrocnemius
Back of lower leg
Flexes sole of foot
Diaphragm
Dome-shaped muscle separating thoracic & abdominal cavities
Helps control breathing

32. Major Muscles of Body MUSCLE LOCATION FUNCTION Hamstring
Posterior thigh
Extends hip and flexes knee
Hamstring is actually the 3 muscles below
1. Semitendinosus
2. Semimembranosus
3. Bicepts femoris

33. Next unit is ___________System
The End!!!
Next unit is ___________System