Download Skeletal Muscles

The Muscular System
MUSCLES
• Approximately 40% of your body weight
• Approximately 650 muscles
• Muscles only pull (they can’t push)
• You have over 30 facial muscles
• Eye muscles move more than 100,000 times a day
Muscle Functions:
Muscle plays six important roles in the body:
1.
2.
3.
4.
Produce skeletal movement
Maintains posture and body position
Support soft tissues (abdominal wall & pelvic cavity)
Guard entrances and exits (digestive and urinary
tracts)
5. Maintain body temperature (energy is converted to
heat)
6. Store nutrient reserves (proteins are broken down &
amino acids are used)
There are 3 types of muscle tissue
1. Skeletal
2. Cardiac
3. Smooth
Skeletal Muscles
• - organs that are composed mainly of skeletal
muscle tissue, but they also contain connective
tissues, nerves, and blood vessels.
• Each cell is a single muscle fiber.
• Muscle fibers form bundles called fascicles.
• Directly or indirectly attached to the bones of
the skeleton
Organization of Skeletal Muscle
Tissue:
Three layers of connective tissue are part of each
muscle:
1. Epimysium – dense layer of collagen fibers that
surround the entire muscle
2. Perimysium – divides the muscle into a series of
compartments each containing a bundle of muscle
fibers (fascicle); contains collagen & elastic fibers,
blood vessels and nerves that maintain blood flow
3. Endomysium – flexible, elastic connective tissue
layer; surrounds the individual skeletal muscle cells
and interconnects adjacent muscle fibers
Fascicle Arrangement
• The muscle fibers in a single fascicle are parallel, but the
organization of fascicles in skeletal muscles can vary
• The arrangement is correlated with muscle power and
range of motion (structure determines function)
• Skeletal muscles are classified as:
1. Parallel muscles (most common) – fascicles are
parallel to the long axis of the muscle
2. Convergent muscles – converge at a common
attachment site; fibers spread out and pull in different
directions
3. Pennate muscles – form a common angle with the
tendon
4. Circular muscles – cocentrically arranged around an
opening
Organization of Skeletal Muscle
Tissue:
• End of the muscle, the collagen fibers
of the epimysium, perimysium, and
endomysium come together to form
a tendon or aponeurosis
• Tendons and aponeuroses attach
muscles to bone
• Origin – where the fixed end of the
muscle attaches to the bone
(cartilage or connective tissue)
• Insertion – where the movable end
of the muscle attaches to another
structure
Origin/Insertion Example:
• Gastrocnemius – calf muscle
that extends from the distal
portion of the femur to the
calcaneus
• When it contracts it pulls the
calcaneus toward the knee
• Origin – femur
• Insertion - calcaneus
Naming of Skeletal Muscles:
 Direction of muscle fibers
Example: rectus (straight)
 Relative size of the muscle
Example: maximus (largest)
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.36a
Naming of Skeletal Muscles:
 Location of the muscle
Example: many muscles are named
for bones (e.g., temporalis)
 Number of origins
Example: triceps (three heads)
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.36b
Naming of Skeletal Muscles:
 Location of the muscles origin and insertion
 Example: sterno (on the sternum)
 Shape of the muscle
 Example: deltoid (triangular)
 Action of the muscle
 Example: flexor and extensor
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.37
Axial and Appendicular
Muscles:
• Axial muscles arise on the axial skeleton (60% of
skeletal muscles)
• Position the head and spinal column and move the
rib cage
• Appendicular muscles stabilize and move the
appendicular skeleton (40% of skeletal muscles)
Head and Neck Muscles
Figure 6.14
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.38
Trunk Muscles
Figure 6.15
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.39
Deep Trunk and Arm Muscles
Figure 6.16
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.40
Muscles of the Pelvis, Hip, and
Thigh
Figure 6.18c
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.41
Muscles of the Lower Leg
Figure 6.19
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.42
Superficial Muscles: Anterior
Figure 6.20
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.43
Superficial Muscles: Posterior
Figure 6.21
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.44
Muscle Actions:
• Agonist (prime mover) – a muscle whose contraction
is mostly responsible for producing a particular
movement
Example – biceps brachii
• Antagonist – a muscle whose action opposes that of
a particular agonist
Example – triceps brachii
• Agonists and antagonists are functional opposites
• Synergists – help a larger agonist work efficiently
Muscle Tone and Contractions
• Muscle Tone – resting tension in a skeletal
muscle
• Isotonic muscle contraction – tension rises and
the skeletal muscle’s length changes (lifting)
• Isometric muscle contraction – the muscle as a
whole does not change length, and the tension
produced never exceeds the load (holding)
Types of Ordinary Body
Movements:
 Flexion – bending at the joint
 Extension - straightening at the joint
 Hyperextension – over extension of joint
 Rotation – rotating on axis
 Abduction – moving away from the midline
 Adduction – moving toward the body
 Circumduction – circular movement
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.32
Body Movements
Figure 6.13
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.33
Special Movements:
 Dorsiflexion – movement of foot in
upward motion
 Plantar flexion – movement of foot
in downward motion
Special Movements
 Inversion = tilt of
foot away from
midline
 Eversion = tilt of
foot towards midline
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.34
Special
Movements
 Opposition
 Supination
 Pronation
Muscle Analysis
• Choose a sport or activity where movement is involved
(football, yoga, softball, swimming, skate boarding, etc.)
• Write a short story about the sport/activity (choose a
competition, game, or practice)
• Include 10 muscles and 5 movements in the story that the
participant(s) demonstrates
• Circle the muscle names & underline the movements in
your story
• You must include one picture with your story
• Use the “arts and supplies” to complete your final draft
• The story is a classwork grade of 20 points (1 point for each
required term and 5 points for your picture/creativity)
Muscular System Injuries
• TSWBAT identify injuries of the
muscular system.
• TSWBAT compare a strain and sprain.
• TSWBAT list the elements of RICE for
first aid of muscular system injuries.
Strain vs. Sprain
What is a strain?
Strains are injuries that involve the stretching or
tearing of a musculo-tendinous (muscle and tendon)
structure
What is a sprain?
A sprain is an injury involving the stretching or tearing
of a ligament (tissue that connects bone to bone)
Ankle Sprains
Examples of Strains
Sprains and Strains are categorized
according to severity.
Grade I (mild) sprain or strain involves
some stretching or minor tearing of a
ligament or muscle.
Grade II (moderate) sprain or strain is a
ligament or muscle that is partially torn
but still intact.
Grade III (severe) sprain or strain means
that the ligament or muscle is completely
torn, resulting in joint instability.
First Aid
•R – rest
•I - immobilize (ice)
•C - compression
•E - elevation
Definition - One of nine types of muscular dystrophy, a group of genetic,
degenerative diseases primarily affecting voluntary muscles.
Cause - An absence of dystrophin, a protein that helps keep muscle cells intact.
Information obtained from: http://www.mda.org/disease/dmd.html
DMD continued.....
Onset - Early childhood - about 2 to 6 years.
Symptoms - Generalized weakness first affecting the muscles
of the hips, pelvic area, thighs and shoulders. Calves are often
enlarged.
Progression - DMD eventually affects all voluntary muscles, and
the heart and breathing muscles.
Inheritance - X-linked recessive. DMD primarily affects boys,
who inherit the disease through their mothers. Women can
be carriers of DMD but usually exhibit no symptoms
ACL Surgery:
• Most surgery for ACL injuries involves replacing the
ACL with tissue called a graft
• Usually an autograft (tendon taken from another part
of the body) is used
• The most common grafts used are the tendon of the
kneecap or one of the hamstring tendons
• Another choice is allograft tissue, which is taken from a
deceased donor
Paralysis:
• Loss of muscle function in part of your body
• Occurs when something goes wrong with the way
messages pass between your brain and muscles
• Can be complete or partial; occur on one or both
sides of your body; one area or widespread
• Paraplegia: lower half of your body
• Quadriplegia: arms and legs
• Due to strokes, injuries (spinal cord), or a broken neck