Muscular System
1H06.01 Describe the structure of the muscles
A. Muscles
1. Nearly half our weight comes from muscle tissue
2. There are 650 different muscles in the human body
3. Muscles give shape and form
4. Muscles produce body heat
B. Types of muscles
1. Voluntary
a. Skeletal – muscles attached to bone
b. The sarcolemma is the cell membrane
2. Involuntary
a. Smooth (visceral) – found in internal organs
b. Cardiac – found in heart
3. Sphincter – circular muscles in openings between esophagus and stomach, anus and urethra
C. Principal skeletal muscles
1. Biceps brachii
2. Brachioradialis
3. Buccinator
4. Deltoid
5. Diaphragm
6. External oblique
7. Hamstrings
8. Gastrocnemius
9. Gluteus maximus
10. Gluteus medius
11. Intercostal muscles
12. Latissiumus dorsi
13. Masseter
14. Pectoralis major
15. Quadriceps femoris
16. Rectus abdominus
17. Rectus femoris
18. Sartorius
19. Soleus major
20. Sternocleidomastoid
21. Tibialis anterior
22. Trapezius
23. Triceps brachii
24. Vastus lateralis
25. Vastus medialis
1H06.02 Analyze the function of the muscular system
A. Responsible for:
1. Body movement
2. Posture
3. Body heat
B. Types of muscles
1. Voluntary
a. Skeletal – muscles attached to bone
b. The sarcolemma is the cell membrane
2. Involuntary
a. Smooth (visceral) – found in internal organs
b. Cardiac – found in heart
3. Sphincter – circular muscles in openings between esophagus and stomach, anus and urethra
C. Characteristics
1. Contractibility – muscle becomes shorter and thicker causing muscle movement
2. Excitability – respond to stimuli
3. Extensibility – ability to stretch muscles
4. Elasticity – ability to return to original length
D. Movement
1. Muscles move bones by pulling on them
2. Groups of muscles usually contract to produce a single movement
a. Motor unit – a motor neuron plus all the muscle fibers it stimulates
b. Neuromuscular junction – junction between the motor neuron’s fiber which transmits the impulse, and the muscle cell membrane
c. Acetylcholine – chemical neurotransmitter, diffuses across the synaptic cleft (carries impulse across synaptic cleft)
d. Muscle fatigue – caused by the accumulation of lactic acid in the muscles
e. Oxygen debt – after exercise, the amount of oxygen needed by the muscle to change lactic acid back to glucose
3. Diaphragm – dome-shaped muscle, separates abdominal and thoracic cavity, aids in breathing
E. Muscle tone – muscles slightly contracted and ready
F. Exercise and training
1H06.03 Identify characteristics and treatment of common muscle
disorders
A. Conditions
1. Atrophy – wasting away of muscle due to lack of use
2. Hypertrophy – an increase in the size of the muscle cell
B. Injury and overuse
1. Strain – muscle tear, symps are pain and swelling, Rx – ice packs
2. Muscle spasm (cramp) – sustained contraction of muscle
3. Myalgia – muscle pain
4. Tendonitis – inflammation of tendon
Unit F: Muscular System
Terminology List
Summer 2005 F.14
1. acetylcholine
2. biceps brachii
3. brachioradialis
4. buccinator
5. cardiac muscle
6. contractability
7. deltoid
8. diaphragm
9. elasticity
10. excitability
11. extensibility
12. external oblique
13. hamstrings
14. gastrocnemius
15. gluteus maximus
16. gluteus medius
17. intercostal muscles
18. involuntary
19. latissimus dorsi
20. masseter
21. motor unit
22. muscle fatigue
23. muscle tone
24. neuromuscular junction
25. oxygen debt
26. rectus femoris
27. pectoralis major
28. quadriceps femoris
29. rectus abdominis
30. sarcolemma
31. sartorius
32. skeletal muscle
33. smooth muscle
34. soleus major
35. sphincter
36. sternocleidomastoid
37. tibialis anterior
38. trapezius
39. triceps brachii
40. vastus lateralis
41. vastus medialis
42. voluntary
Summer 2005 F.14
Disorders and Related Terminology
1. atrophy
2. hypertrophy
3. muscle spasm (cramp)
4. myalgia
5. strain
6. tendonitis
MUSCULAR SYSTEM
“the power system”
MOVEMENT
1. 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.
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.)
Appendix 1H06.02A
MUSCULAR SYSTEM
“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.
THREE MAIN FUNCTIONS
1. Responsible for all body movement.
2. Responsible for body form and shape (posture)
3. Responsible for body heat and maintaining body temperature.
SKELETAL
TYPES OF MUSCLES SMOOTH
CARDIAC
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
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
Cardiac Muscle
· Found only in the heart
· Striated and branched
· Involuntary
· Cells are fused – when one contracts, they all contract
· Involuntary
CHARACTERISTICS OF MUSCLES
· CONTRACTIBILITY – the ability of a muscle to reduce the distance between the parts of its contents or the space it surrounds.
· EXCITEABILITY (IRRITABILITY) – the ability to respond to certain stimuli by producing impulses.
· EXTENSIBILITY – the ability to be stretched.
· ELASTICITY – ability of muscle to return to its original length when relaxing.
MOVEMENT
2. 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.
Rule: A muscle’s insertion bone moves toward its origin bone.
2. Groups of muscles usually contract to
produce a single movement.
· 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
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
Summer 2005 F.14