Download Prime mover - Net Start Class

Connective tissue components
1.Endomysium - Muscle fibers are covered with a delicate connective tissue membrane
2.Perimysium - Groups of skeletal muscle fibers (fascicles) are bound together by a tougher
connective tissue
3.Epimysium - the muscle as a whole is covered by a coarse sheath
4.Tendon - fibrous structures that attach muscles to bones
5.Aponeurosis 6.Tendon sheath -
Size, shape, and fiber arrangement
Parallel
Convergent
Pennate
Bipennate
Sphincter
Attachment of muscles
- point of attachment that does not move when the muscle contracts
-point of attachment that does move when
the muscle contracts
Muscle actions
• Functional classification of muscle groups – always
function in groups/pairs; some contract as some relax
– Prime mover (agonist) – Muscle most responsible for
movement; “action” or “function” of that muscle
– Antagonist – Muscle responsible for the movement
opposite of the prime mover; provides precision and
control during contraction of prime mover; relaxes
while prime mover contracts
– Synergist – Muscles that aid the prime mover;
contract at same time as prime mover
– Fixator – joint stabilizer; maintains posture or balance
during contraction of prime mover
2nd Class Levers
1st Class Levers
Bone = lever
Joint = Fulcrum (F)
Contracting Muscle = Force (P)
Load (L)
3rd Class Levers
How Muscles Are Named
Features used in naming muscles
1.
Location – gluteus, brachii
2.
Function
3.
Shape - deltoid
4.
Direction of fibers – rectus abdominus
5.
Number of heads or divisions – points of
origin
-cep = head
6.
Points of attachment -sternocleidomastoid
7.
Size of muscle – relative size, maximus,
minimus
Hints on how to deduce muscle actions
1.
Be familiar with name, shape, and location
2.
From shape and location, deduce name of origin and insertion bone
3.
Determine which bone moves when muscle contracts
4.
Deduce action—insertion moves toward origin
5.
Deduce which muscle gives a specific action
Muscles Named According To:
Overall Shape
Deltoid
Shaped like delta Δ
Orbicularis
Circular
Platy
Flattened; platelike
Quadratus
Square
Rhomboideus
Diamond-shaped
Trapezius
Trapezoidal
Triangularis
Triangular
Muscles Named According To:
Relative Size
Brevis
Short
Longus
Long
Magnus
Large
Maximus
Largest
Medius
Moderately sized
Minimus
Small
Muscles Named According To:
Direction of Fibers
Oblique
Diagonal to body’s midline
Rectus
Parallel to midline
Sphincter
Circling an opening
Transversus
Right angle to midline
Muscles Named According To:
Actions Produced
Abductor
Abducts a part
Adductor
Adducts a part
Depressor
Depresses a part
Extensor
Extends a part
Flexor
Flexes a part
Levator
Elevates a part
Rotator
Rotates a part
Muscles Named According To:
Regions Found
Brachialis
Arm
Frontalis
Frontal (bone)
Femoris
Femur
Gluteus
Posterior of hip/thigh
Oculi
Eye
Radialis
Radius
Ulnaris
Ulna
1.
2.
3.
4.
5.
6.
Muscles of Facial Expression
occipitofrontalis – raise eyebrows
corrugator supercilii – frowning forehead
orbicularis oculi – blinking
zygomaticus major – laughing
orbicularis oris – puckering
buccinator
Muscles of Mastication (chewing)
1. masseter
2. temporalis
3. pterygoids
1.
2.
3.
4.
Muscles that Move the Head
sternocleidomastoid
semispinalis capitis
splenius capitus
longissimus capitus
Posture
• Good posture
– body alignment that favors function, with least work
– Standing position: head and chest held high; chin,
abdomen and buttocks pulled in; knees bent slightly;
feet firmly on ground 6 in. apart.
• Poor posture
– puts abnormal strain on ligaments and bones
• How Maintained
– Muscle Tone (Tonicity) – when muscles exert a pull
against gravity
Cycle of Life
• During infancy and childhood, muscle
coordination and control allows
developmental sequences to occur
• Degeneration of muscles with age
includes replacement with connective
tissue