ch 11

Muscles based on fascicle arrangement

parallel, convergent, circular, and pennate

Fascicle arrangement- Parallel muscles

Fascicles are parallel to the long axis of the muscle (most common), Some flat (sartorius) and some plump and cylindrical (bicep), Contraction shortens muscle and increases diameter

Examples of parallel fascicle arrangement

bicep brachii, and rectus abdominis, and sartorius

Fascicle arrangement- Convergent

Vesicles widen at one end and converge to a common tendon. Contraction doesn't pull hard due to multi direction, tear drop shaped

Examples of convergent fascicle arrangement

pectoralis

Fascicle arrangement- Circular

Fascicles in concentric, rings around an opening

Examples of circular fascicle arrangement

orbicularis oris, guards entrances

Fascicle arrangement- Pennate

Fascicles form a common angle with a tendon running length of the muscle. Can be unipennate, bipinnate, or multipennate

Unipennate

One angled fascicle on the side of the tendon- fish fin

Example of unipennate fascicle arrangement

extensor digitorum.

Bipinnate

Two angled fascicles on the sides of the tendon- butterflying salmon

Example of bipinnate fascicle arrangement

rectus femoris

Multipennate

Vesicles angled in three directions that converge to a common tendon- bulb of garlic

Example of multipennate fascicle arrangement

deltoid

Lever

A rigid, moving structure, Board, crowbar, or in this case, bone, move on a fixed point called the fulcrum (f), Point on which levers rest or pivot (i.e. The joint)

Applied force (AF)

Pressure required to overcome resistance/load that would oppose or prevent movement, this force is provided by muscle

Load (L)

Resistance of the AF and has to overcome to cause movement, Environmental objects can increase load (weights)

Lever, F, AF

Bones act as the lever, joints act as the fulcrum, and muscles act as the applied force that moves the load

First class levers

AKA seesaw or teeter totter, Fulcrum is centered between the applied force and load (only a few)

example of a first-class levers

head extension- F- joint where the skull meets the spine, L- weight of the head pulling forward, AF- back of the neck muscles pulling down to keep the head up right. Think yes and no movements

Second class lever

AKA wheelbarrow, the load lies between the fulcrum and the applied force (few exist), Small force moves larger weight

Example of second-class levers

ankle/ foot, standing on tiptoes, F- ball of the foot, L- total body weight pressing down through the ankle, AF- calf muscles pulling upward on the heal

3rd class levers

AKA catapult, or tweezers (most common), Applied force is between load and fulcrum, Greatest range of motion (distance) + speed compared to other classes but less strength/force

Example of third-class levers

bicep curl or lifting an object- F- elbow joint, L – weight in your hand , AF- bicep muscle contracting and pulling

Types of muscles based on function

agonist, antagonist, synergist, fixator

Agonist

MOVER, prime mover. Contraction is responsible for a specific movement, Ex- biceps brachii= flexion of elbow, triceps brachii= extension of elbow

Antagonist

OPPOSER, opposes agonist, antagonist of biceps brachii

Synergist

HELPER, contract to help agonist work better, Add more tension or stability during contraction. Ex- brachialis assists biceps brachii

Fixator

ANCHOR, synergist that assists agonist by preventing movement at another joint. Trapezius stabilizes scapula when bicep pulls on it

Muscles based on function whole example- leg extensions

agonist (mover)- quadriceps= squeezes to lock the knee and lift the load, Antagonist (opposer)- hamstring= relaxes to let leg extend, also helps controls the weight on the eccentric (lowering of weight), synergist (helper)- tensor fasciae latae (outer hip muscle) = helps to keep the kneecaps aligned when as you push the weight up, fixator (anchor)- core and glutes= tighten to keep the body in the seat and aligned to move the weight effectively.

Muscle necessary for breathing

intercostals- inhale and exhale, and diaphragm- inhaling