Muscular System - Notes Outline

Muscular System

1H06.01Describe 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

1H06.02Analyze the function of the muscular system

  1. Responsible for:
  2. Body movement
  3. Posture
  4. 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
  5. Movement
  1. Muscles move bones by pulling on them
  2. Groups of muscles usually contract to produce a single movement
  3. Motor unit – a motor neuron plus all the muscle fibers it stimulates
  4. Neuromuscular junction – junction between the motor neuron’s fiber which transmits the impulse, and the muscle cell membrane
  5. Acetylcholine – chemical neurotransmitter, diffuses across the synaptic cleft (carries impulse across synaptic cleft)
  6. Muscle fatigue – caused by the accumulation of lactic acid in the muscles
  7. 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

  1. Muscle tone – muscles slightly contracted and ready
  2. Exercise and training

1H06.03Identify 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