Download Muscular System

Muscular System
Muscle Functions
•
•
•
•
Movement
Protection
Posture and Support
Heat
Muscle
• Over 600 muscles
• 40 – 50 % of total body weight
• 215 pairs of muscles
– Aggregate muscle action
Muscle Nomenclature
• Appearance
• Location
• Function
Muscle Nomenclature
• Shape
– Deltoid
– rhomboid
Muscle Nomenclature
• Size
– Gluteus Maximus
– Teres Minor
Muscle Nomenclature
• Number of Divisions
– Biceps Brachii
Muscle Nomenclature
• Direction of fibers
– External Oblique
Muscle Nomenclature
• Location
– Rectus femoris
– Palmaris longus
Muscle Nomenclature
• Points of Attachement
– Coracobrachialis
– Flexor Digitorum Longus
Muscle Nomenclature
Action
– Erector spinae
Muscle Nomenclature
Action and Shape
Pronator quadratus
Action and Size
Adductor magnus
Shape and Location
Serratus anterior
Muscle Nomenclature
Location and Attachment
Brachioradioalis
Location and Number of Divisions
Biceps femoris
Muscle Nomenclature
Groups of muscles
Shape
hamstrings
Number of Divisions
quadriceps
triceps
Muscle Nomenclature
Groups of muscles
Location
peroneals
abdominal
shoulder girdle
Action
hip flexors
rotator cuff
Myofilaments
• Actin – thin proteins
• Myosin – thick proteins
Myofilaments
Sarcomere
Contractile unit of a muscle fiber
What fiber joins muscles to bones?
Tendons
Muscle-tendon Functions
Joints ROM
• Flexibility
Maximum force on a unit
• Strength
Rate of muscular force applied
• Muscular power
to move a load
• Muscular endurance
Ability of a muscle to exert a
force repeatedly or constantly
Muscle fatigue, soreness, pain – build-up of lactic acid in
the muscles
Fibers and Shape
• Determine a muscle’s ability to exert force
– Cross section diameter
• Greater = greater
• Determine range through which it can exert
force onto the bone it is attached
– Ability to shorten
• Longer muscles shorten through a greater range = more
effective moving joints through large ranges of motion
Classification by Fiber Arrangement
• Parallel
run longitudinally or somewhat
parallel with the muscle’s long axis
• Pennate
(feather-like) tendons run down the
muscle’s long axis, and fibers run obliquely to
the tendon
Parallel Structures
• Fibers are longer
• Run parallel to the length of the muscle
• Pull bones through a greater ROM
• Flat
Parallel Structures
– Thin and broad
• Rectus abdominus
• External oblique
• Fusiform
– Spindle shaped with a central belly that tapers to
tendons on the ends
• Brachialis
• Brachioradialis
• Strap
– More uniform
• Sartorius
Parallel Structures
• Radiate (triangular or fan-shaped)
– Combo of flat and fusiform
• Pectoralis major
• Trapezius
• Sphincter (circular)
– Endless strap around openings
• Orbicularis oris
• Orbicularis oculi
Pennate Structures
•
•
•
•
Shorter fibers run oblique to tendons
Gearter cross section = greater force
Most muscles in the body
To provide more force than fusiform, but less
ROM
Example: sit-ups
Pennate Structures
• Types
– Unipennate . . . Biceps femoris
– Bipennate . . . Rectus femoris
– Multipennate . . . Deltoid
Class Activity
• Scavenge the room.
• Find something that would be considered
fusiform.
• Find something that would be considered
pennate
Class Activity
• Classify the following items as:
fusiform
unipennate
bipennate
multipennate
Skeletal Muscle Tissue Properties
• Irritability or
Excitability
responds to nervous stimuli
• Conductivity
wave of excitement
• Contractility
pulling ends together
• Distensibility or
Extensibility
stretched
• Elasticity
recoil from a stretch
Reciprocal Inhibition or Innervation
• Agonists
muscles that cause or help cause motion
• Antagonists
perform opposite to the movement being
done
Example: hip flexors & hip extensors
• Synergistic Muscles – same function, work
together
Powerpoint Presentations
Utilize the following website to chose 5 muscles (the may
be random or close together):
http://www.ptcentral.com/muscles/index.html
For each of the muscles use the internet or other resources
to find the following:
1. Identify a movement (ex. flexing the upper arm)
2. State the muscle that is the agonist for the movement
3. State if there are any synergists acting in conjunction
with the agonist for this action
4. State the antagonist of the agonist for the movement
5. For the agonist only state the muscle fiber arrangement
type ( Ex. fusiform, unipennate, bipennate, or
multipennate)
For the remaining points, chose 1 of the 5 only to provide the
following:
6. Construct or draw (paint) a figure showing the muscle fiber
arrangement as well as it correct anatomical position.
7. Provide a table that distinguishes the muscle properties for
the muscle in #6 by a picture-graph. You may cut the table
and create a slide for each property and picture-graph if
desired.
( Ex. contractibility
)
8. Find or create a video showing the same muscle ( in #6) at
work (contracting/extending)