muscular system chapter 7. © 2004 delmar learning, a division of thomson learning, inc. types of...
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MUSCULAR SYSTEMMUSCULAR SYSTEM
Chapter 7
© 2004 Delmar Learning, a Division of Thomson Learning, Inc.
TYPES OF MUSCLESTYPES OF MUSCLES
• Skeletal muscles• Smooth muscle• Cardiac muscle• Sphincter (dilator) muscles
© 2004 Delmar Learning, a Division of Thomson Learning, Inc.
CHARACTERISTICS CHARACTERISTICS OF MUSCLESOF MUSCLES
• All muscles have four common characteristics:– Contractibility– Excitability or irritability– Extensibility– Elasticity
© 2004 Delmar Learning, a Division of Thomson Learning, Inc.
MUSCLE ATTACHMENTS MUSCLE ATTACHMENTS AND FUNCTIONSAND FUNCTIONS
• Muscles are attached to the bones by non-elastic cords called tendons
• Origin– part attached to the bone
• Insertion– part attached to movable part
© 2004 Delmar Learning, a Division of Thomson Learning, Inc.
MUSCLE ATTACHMENTS MUSCLE ATTACHMENTS AND FUNCTIONSAND FUNCTIONS
• Muscles are arranged in pairs– prime mover produces movement
in a single direction– antagonist moves bone in opposite
direction
© 2004 Delmar Learning, a Division of Thomson Learning, Inc.
CONTRACTION OF SKELETAL CONTRACTION OF SKELETAL MUSCLEMUSCLE
• Motor unit is the motor neuron plus all the muscle fibers it stimulates
© 2004 Delmar Learning, a Division of Thomson Learning, Inc.
MUSCLE FATIGUEMUSCLE FATIGUE
• Muscle fatigue is caused by an accumulation of lactic acid in muscles
• Blood is unable to transport enough oxygen to the bloodstream
• Lactic acid accumulates in the muscle, impeding contraction and causing fatigue and cramping
© 2004 Delmar Learning, a Division of Thomson Learning, Inc.
MUSCLE TONEMUSCLE TONE
• Muscle contractions may be:– Isotonic
•muscles contract and shorten
– Isometric•tension increases but muscle does not
shorten
© 2004 Delmar Learning, a Division of Thomson Learning, Inc.
MUSCLE TONEMUSCLE TONE
• Atrophy is the shrinking of muscles from disuse
• Hypertrophy is due to over-exercise and leaves muscles enlarged
© 2004 Delmar Learning, a Division of Thomson Learning, Inc.
PRINCIPLE PRINCIPLE SKELETAL MUSCLESSKELETAL MUSCLES
• Head muscles• Neck muscles• Trunk and extremity muscles
© 2004 Delmar Learning, a Division of Thomson Learning, Inc.
MUSCLES OF THE MUSCLES OF THE HEAD AND NECKHEAD AND NECK
• Muscles of the head and neck control human facial expressions
• Muscles of mastication control the mandible (lower jaw)
© 2004 Delmar Learning, a Division of Thomson Learning, Inc.
MUSCLES OF THE MUSCLES OF THE UPPER EXTREMITIESUPPER EXTREMITIES
• Muscles of the upper extremity help to move the:– Shoulder (scapula)– Arm (humerus)– Forearm– Wrist– Hand– Fingers
© 2004 Delmar Learning, a Division of Thomson Learning, Inc.
MUSCLES OF THE TRUNKMUSCLES OF THE TRUNK
• Trunk muscles control breathing and the movements of the abdomen and the pelvis– External intercostals– Diaphragm– Rectus abdominis– External oblique– Internal oblique
© 2004 Delmar Learning, a Division of Thomson Learning, Inc.
MUSCLES OF THE MUSCLES OF THE LOWER EXTREMITIESLOWER EXTREMITIES
• Assist in the movement of the thigh, leg, ankle, foot, and toes– Gluteus maximus - Tibialis anterior– Gluteus medius -
Gastrocnemius– Tensor fasciae - Soleus– Peroneus longus - Sartorius– Rectus femoris
© 2004 Delmar Learning, a Division of Thomson Learning, Inc.
HOW EXERCISE AND HOW EXERCISE AND TRAINING CHANGE MUSCLESTRAINING CHANGE MUSCLES• Effect of training on muscle
efficiency:– Improved coordination– Improvement of the respiratory
and circulatory system– Elimination or reduction of excess
fat– Improved joint movement
© 2004 Delmar Learning, a Division of Thomson Learning, Inc.
HOW EXERCISE AND HOW EXERCISE AND TRAINING CHANGE MUSCLESTRAINING CHANGE MUSCLES• Effects of Training on Muscle
Strength– Increase in muscle size– Improved antagonistic muscle
coordination– Improved functioning in the cortical
brain region
© 2004 Delmar Learning, a Division of Thomson Learning, Inc.
INTRAMUSCULAR INTRAMUSCULAR INJECTIONSINJECTIONS
• Injections are made into the muscle, usually the deltoid muscle of the upper arm, vastus lateralis (anterior thigh), dorsal gluteal or ventral gluteal or buttocks
© 2004 Delmar Learning, a Division of Thomson Learning, Inc.
MUSCULOSKELETAL MUSCULOSKELETAL DISORDERSDISORDERS
• Atrophy• Strain• Spasm• Myalgia
• Fibromyalgia• Hernia
– Abdominal hernia
– Inguinal hernia– Hiatal hernia
© 2004 Delmar Learning, a Division of Thomson Learning, Inc.
MUSCULOSKELETAL MUSCULOSKELETAL DISORDERSDISORDERS
• Flatfeet• Tetanus• Torticollis• Muscular
dystrophy
• Mysathenia gravis
• Recreational injuries– Tennis elbow– Shin splints– Rotator cuff
disease