Download Three muscle types

8.7 SKELETAL MUSCLE ACTION
SKELETAL MUSCLE ACTIONS
- Skeletal muscles
provide a variety of
body movements
- The movements largely
depend on the origin
and insertion of the
muscle
SKELETAL MUSCLE ACTIONS
- The origin in the
muscle attachment at
the immovable end
- For the biceps brachii,
this is two places on
the scapula
SKELETAL MUSCLE ACTIONS
- The insertion is the
movable end, it is
pulled towards the
origin
- The insertion on the
biceps brachii is on the
radius
SKELETAL MUSCLE ACTIONS
- Skeletal muscles almost
always function in
groups.
- For a body
movement to occur,
more than one muscle
must contract.
SKELETAL MUSCLE ACTIONS
- The main muscle that is
responsible for a
movement is called the
prime mover (agonist)
- Muscles that contract to
assist the prime mover
are called synergists
SKELETAL MUSCLE ACTIONS
- Some muscles can
resist the prime mover,
these are called
antagonists
- If both a prime mover
and antagonist contract,
then the part they act
on is rigid
SKELETAL MUSCLE ACTIONS
- For a motion to
happen, the prime
mover contracts
and the antagonists
relaxes
MUSCLES OF FACIAL EXPRESSION
MUSCLES OF FACIAL EXPRESSION
- Facial muscles
- Enable us to
communicate
feelings through
facial expression
MUSCLES OF FACIAL EXPRESSION
Epicranius
- Frontalis
- Epicranial aponeurosis
- Occipitalis
MUSCLES OF FACIAL EXPRESSION
Epicranius
- Origin – occipital bone
- Insertion – skin and
muscle around superior
portion of eyes
- Action: raises eyebrows
MUSCLES OF FACIAL EXPRESSION
Orbicularis oculi
- Muscle around the eye
- Origin: maxillary/frontal
bones
- Insertion: skin around the
eye
- Action: closes eye
MUSCLES OF FACIAL EXPRESSION
Orbicularis oris
- The kissing muscle
- Origin: muscles near
the mouth
- Insertion: skin of lips
- Action: closes and
protrudes lips
MUSCLES OF FACIAL EXPRESSION
Buccinator
- Cheek muscle
- Means “trumpet”
- Origin: outer surface of
maxilla/mandible
- Insertion: orbicularis oris
- Action: compresses cheeks
inward
- Helps you keep food between
teeth
MUSCLES OF FACIAL EXPRESSION
Zygomaticus
- “smiling” muscle
- Origin: zygomatic arch
- Insertion: orbicularis oris
- Action: raises corner of
mouth
MUSCLES OF MASTICATION
(CHEWING)
MUSCLES OF MASTICATION
Masseter
- Origin: Lower part of
zygomatic arch
- Insertion: Lateral
surface of the mandible
- Action:
elevates mandible
MUSCLES OF MASTICATION
Temporalis
- Origin: temporal bone
- Insertion: Lateral surface
of mandible
- Action: Elevates
mandible
MUSCLES OF MASTICATION MOVEMENTS