Download Muscular System

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
Summer 2005 F.1
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
Summer 2005 F.2
Unit F: Muscular System
Terminology List
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.3
Disorders and Related Terminology
1.
2.
3.
4.
5.
6.
atrophy
hypertrophy
muscle spasm (cramp)
myalgia
strain
tendonitis
Summer 2005 F.4
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.
Summer 2005 F.5
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
Summer 2005 F.6
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
Summer 2005 F.7
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
Summer 2005 F.8
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.
Summer 2005 F.9
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)
Summer 2005 F.10

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
Diaphragm
flattens when you
breathe in.
Summer 2005 F.11
Summer 2005 F.12
Summer 2005 F.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
Summer 2005 F.14