1. Muscular System
Chapter 7
Pages 118 – 142

2. Functions of Muscular System
Page 119
Functions of Muscular System
Three main responsibilities:
Body movement
Body form and shape to maintain posture
Body heat to maintain body temperature

3. Page 119
Types of Muscles
Skeletal muscle – voluntary; Striated; Attached to bone
Sarcolemma – cell membrane
Sarcoplasm – cytoplasm
Fascia – a band of muscular fibers (muscle cells) that envelops, separates, or binds muscles or groups of muscles
Smooth muscle – involuntary; Non-striated; Controlled by the autonomic nervous system
Cardiac muscle – In the heart only; Involuntary; Striated & branched
Under conscious control (voluntary)
Not under conscious control (involuntary)
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Sphincter muscles or dilator muscle are special circular muscles in the openings between the esophagus & stomach, & the stomach & small intestine. Found in the anus, the urethra, & the mouth

4. Characteristics of Muscles
Page 120
Characteristics of Muscles
Contractibility – Shorten in response to a stimuli
Excitability (irritability) – the ability to respond to stimuli
Action potentials – Electrical signals
Extensibility – ability to be Stretched
Elasticity – Return to original length when relaxing

5. Muscle Attachments & Functions
Page 121
Muscle Attachments & Functions
Over 650 muscles in the body
Muscles must be attached to bones for leverage
Muscles only pull, never push
Attached to bone by tendons
Muscles are attached at both ends
Attachments may be to bones, cartilage, ligaments, tendons, skin, or to each other
Origin and insertion
Origin = the part of the of a skeletal muscle that is attached to a fixed structure or bone; it moves the least during muscle contraction
Insertion = the other end, attached to a movable part; it is the part that moves most during a muscle contraciton

6. Muscle Attachments & Functions
Pages 121 – 122
Muscle Attachments & Functions
Prime mover – Movement in a single direction
Antagonist – Pulls from the opposite direction
Synergists – Steady the movement or stabilize the joint
Muscles of the upper arm:
Biceps – one end is attached to the scapula & humerus (its origin & remian stationary) other end attach to the radius of the lower arm (it’s insertion & moves when the muscle is flexed)
Triceps is antagonist to the bicep

7. Sources of Energy & Heat
Page 122
Sources of Energy & Heat
Narrow range of normal body temperature (98.6° F to 99.8° F)
Major source of energy is ATP (adenosine triphosphate)
Production of ATP requires oxygen, glucose, & other materials
By-product is lactic acid

8. Contraction of Skeletal Muscles
Page 122 – 123
Contraction of Skeletal Muscles
Movement of muscles is a result of two major events:
Myoneural stimulation
Stimulation by a nerve impulse causes contraction (muscle twitch)
Motor unit consists of a nerve cell plus the muscle fiber it stimulates
neuromuscular junction = junction between the nerve cell axon & the muscle cell membrane
Contraction of muscle proteins
Begins with an action potential
Requires energy

9. Effects of Aging Page 123 SB Muscle atrophy
Fibrous tissue replaces the muscle tissue
Decrease in muscular strength & endurance
Loss of energy storage (Fatigue)

10. Page 123
Muscle Fatigue
Caused by accumulation of lactic acid in the muscles
When not enough oxygen can be transported to oxidize all the glucose in the muscle
Muscles contract anaerobically (without oxygen)
Excess lactic acid causes fatigue & cramps
Need to rest & repay oxygen debt to change the lactic acid back to glucose

11. Pages 123 – 124
Muscle Tone
Muscle tone = slightly contracted & ready to pull. Achieved through proper nutrition & regular exercise
Isotonic = When muscles contracts and shorten
Isometric = When the tension increases but the muscle does not shorten
Atrophy (weak & shrink from disuse) & hypertrophy (enlarged from over use)

12. Principle Skeletal Muscles
Page 124
Principle Skeletal Muscles
Skeletal or voluntary muscles = These move the skeleton
Naming of Skeletal Muscles
Named by Location, Size, Direction, Number of origins, Location of origin & insertion, & action
Not all muscles are named by this method
Also control movement of the eyeballs, eyelids, lips, tongue, & skin

13. Page 125
Muscles
656 muscles
327 antagonistic muscles & two unpaired muscles
Orbicularis oris & Diaphragm
Head muscles
Neck muscles
Trunk & extremity muscles

14. Muscles of the Head & Neck
Page 125
Muscles of the Head & Neck
Control expressions
Mastication
Movement of the head

15. Important to you

16. Trunk & Extremities Pages 126 – 130
Muscles of the upper extremities – Shoulder, arm, & hand movements
Muscles of the trunk – Breathing & movement of the abdomen & pelvis
Muscles of the lower extremities – Thigh, leg, ankle, foot, & toes

17. Page 129
Figure 7 – 11

18. Page 130
Figure 7 – 12

19. Page 131
Figure 7 – 13

20. Exercise Page 131 Alters the size, structure, & strength of a muscle
Atrophy – Shrinking of muscle size
Hypertrophy – Enlargement of muscle size
Muscles can regenerate only to a limited degree
If damage is extensive scars will form
Improved coordination
Improved respiratory & circulatory system
Elimination or reduction of excess fat
Improved joint movement

21. Training & Strength Pages 131 – 132
Increased Strength (capacity to do work)
Increase in muscle size
Improved antagonistic muscle coordination
Improved functioning in the cortical brain region, where the nerve impulses that start muscular contraction originate

22. Message Muscles Page 132 – 134 Potential health benefits
Terms used in massage therapy to describe type of massage
Location of surface body muscles
Physiotherapy and general massage
Physiotherapy physical therapy

23. Electrical Stimulation
Page 114
Electrical Stimulation
Passing electrical currents through the skin into the body for therapeutic uses
Stimulate nerve tissue
Do not produce heat or cold
Used in physical therapy

24. Intramuscular Injections
Page 114
Intramuscular Injections
Deltoid (upper arm)
Vastus lateralis (anterior thigh)
Dorsal gluteal or ventral gluteal (buttocks)

25. Musculoskeletal Disorders
Page 134
Musculoskeletal Disorders
Muscle atrophy – occur to muscles used infrequently
Muscle strain – the overstretching or tearing of a muscle. A strain is less serious than a sprain.
Muscle spasm (cramp) – a sustained contraction of the muscle
Myalgia – a term used to describe muscle pain
Dystonia – a condition characterized by involuntary muscle contractions that cause repetitive movements or abnormal pictures. The cause is unknown.

26. Musculoskeletal Disorders
Page 134 – 135
Musculoskeletal Disorders
Hernia – occurs when an organ protrudes through a weak muscle
Flatfeet (talipes) – the arch of the foot is lower than normal
Tetanus (lockjaw) – an infectous disease characterized by continuous spasms of the voluntary muscles.
Torticollis (wry neck) – a condition in which the head becomes persistently turned to one side, often associated with painful muscle spasms

27. Musculoskeletal Disorders
Page 135
Musculoskeletal Disorders
Muscular dystrophy – a group of diseases in which the muscle cells deteriorate.
Myastenia gravis – occurs when the connection between the nerves & muscle is lost.
Heel spur – a calcium deposit in the plantar fascia near its attachment to the calcaneus bone can cause plantar fasciitis
Plantar fasciitis – inflammation of the plantar fascia on the sole of the foot

28. Recreational Injuries
Page 136
Recreational Injuries
Tennis elbow – the tendon that connects the arm muscles to the elbow becomes inflamed because of repetitive use of the arm & underconditioning
Shin splints – injury to the muscle tendon in the front of he shin (usually from jogging)
Rotator cuff injury – inflammation of a group of tendons that act together to stabilize the shoulder joint.

29. Chapter 7
Treatment
Short-term treatment for sprains, tears, pulls, & other minor muscle or joint injuries
RICE
R = Rest
I = Ice
C = Compression
E = Elevation