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•Muscles are contractile
organs responsible for
the voluntary and
involuntary movements
of animals.
1. Skeletal muscle
- allows for all voluntary movement
- appears to be striated when looked
at under a microscope.
2. Cardiac muscle
- controls the involuntary beating
of the heart
- appears striated under a
microscope.
3. Smooth muscle
- responsible for all other
involuntary movement, such as
breathing, digestion, peristalsis,
blinking, etc.
Ambulation
moving from one place to
another
Abduction
moving away from the
median plane
Adduction
moving towards the median
plane
Flexion
moving the distal part of the
limb towards the body
Extension
moving the distal part of the
limb away from the body
All muscles can do is
CONTRACT
or
RELAX,
so they generally work in
pairs.
For any particular action, the
muscles involved can be
classified as:
1) Agonist
2) Antagonist
Agonist
prime mover of a joint
Antagonist
opposes movement of the
agonist
Example
For elbow flexion,
the agonist is the bicep
the antagonist is the tricep.
Example
For elbow extension,
the agonist is the tricep
the antagonist is the bicep.
Masseter
– superficial muscle of the
cheek
Masseter
Trapezius
– superficial triangular muscle of
the shoulder
Trapezius
Latissimus dorsi
– long, superficial, dorsal muscle
that attaches the humerus to
the lumbar region of the back
Latissimus dorsi
Abdominal obliques
– large flat muscles that support
digestive and reproductive
organs
External abdominal
oblique
Gluteals
– large muscle of the upper
hindquarters
Gluteals
Biceps femoris
– lateral superficial muscle, one
of three which forms the
“hamstrings”
Biceps
femoris
Biceps brachii
– primary flexor of the elbow
joint
Triceps brachii
– primary extensor of the
elbow joint
Triceps
brachii
Pectorals
– primary adductors of the
forelimbs
Pectorals
Serratus ventralis
– attaches forelimb to trunk
(no collarbone!)
Brachiocephalicus
Deltoid
Intercostal
Semitendinous
Gastrocnemius