chapter 11: muscular system Flashcards
explain the origin and insertion
In the limbs, the origin of a muscle is usually proximal and the insertion
is usually distal.
**Ordinarily, the attachment of a muscle’s tendon to the stationary bone is called the origin.
**the attachment of the muscle’s other tendon to the movable bone is called the insertion.
**
Where is the belly of the muscle that extends the forearm located?
** The belly is fleshy portion of the muscle between the tendons.
**TRICEPS
Lever system and Leverage
In producing movements, bones are levers, joints are fulcrums.
** levers moves along a fixed position.
What is mechanical advantage
If the load is closer to the fulcrum and the eff ort farther from the fulcrum, then only a relatively small eff ort is required to move a large load over a small distance. chewing using back teeth.
Mechanical disadvantage
load is farther from the fulcrum and the eff ort is
applied closer to the fulcrum, then a relatively large eff ort is required to move a small load (but at greater speed. eg chewing using front teeth
categories of levers
**first class EFL examples see saws, scissors. Raising head up to look t the sky.
** Second class ELF examples
** Third class FEL
(QR)List the types of muscle organs by arrangement of fascicles
-Fascicular arrangement affects a muscle’s power and ROM.
*Parallel (flat tendons)
** fusiform (spindle-shaped; muscle tapers towards flat tendons);
** circular (sphincters);
** triangular (broad area, thick central tendon – pec major)
**Pennate (=feather-shaped; short fascicles with tendon extending along length of muscle):
Unipennate (fascicles on one side); bipennate (fascicles on both sides); multipennate (several tendons, fascicles attach obliquely – deltoid
How does fascicle arrangement influence muscle function? Give examples.
Greater cross-sectional area -> more contractile force (eg pennate muscles)
Longer fibres -> more range of motion (eg parallel muscles).
prime mover(agonist)
prime mover (also known as an agonist) refers to the muscle or group of muscles primarily responsible for generating a specific movement. It contracts to cause an action. Example Biceps
Antagonist
the antagonist stretches and yields to the effects of the prime mover by stretching. Triceps
NOTE
With an opposing pair of muscles, the roles of the prime mover and antagonist can switch for different movements. When lowering a road, triceps contacts and becomes the agonist/prime mover while the biceps stretches and becomes the antagonist. If both contract at the same time with equal force there will be no movement.
What are muscles that contract and stabilize the intermediate joints called?
senergist
Whats a fixator
fixators, stabilizing the origin of the prime mover so that the prime mover can act more efficiently eg scapula. The stabilize at proximal end while movement happen at the distal end.
What is a group of skeletal muscles, their blood vessels, and nerves called
compartment
Checkpoint
1.Using the terms origin, insertion, and belly, describe how skeletal muscles produce body movements by pulling on bones.
2.List the three types of levers, and give an example of a first-, second-, and third-class lever found in the body.
3.Define the roles of the prime mover (agonist), antagonist, synergist, and fixator in producing various movements of the free upper limb.
What is a muscle compartment?
Explain the facial movements made by Occipitalfrontalis- frontal belly
Draws scalp anteriorly, raises eyebrows, and wrinkles skin of forehead horizontally as in look of surprise.
Occipitalfrontalis- Occipital belly moves which skin
Draws scalp posteriorly.
MOUTH MUSCLES movements:
Orbicularis oris ,moves
Closes and protrudes lips, as in kissing; compresses lips against teeth; and shapes lips during speech
Zygomaticus major
Draws angle of mouth superiorly and laterally, as in smiling.
Buccinator moves
whistling, blowing, and sucking, chewing,
ORBIT AND EYEBROW MUSCLES
Orbicularis oculi
closes eyes.
Muscles of the Head That Move the Tongue and Assist in Mastication and Speech:
** They move the mandible (lower jawbone) at the temporomandibular joint (TMJ).
** masseter:origin- maxilla and zygomatic arc.
Insertion- angle and ramus of mandible.
-Elevates mandible, as in closing mouth.
**temporalis: Origin- Temporal bone
Insertion- Coronoid process and ramus of mandible.
-Elevates and retracts mandible.
Origin an insertion of the masseter
Origin = maxilla and zygomatic arch
Insertion = angle and ramus of the mandible
Muscles of the Neck That Move the Head:
-Sternocleidomastoid
Origin- Sternal head: manubrium of sternum; clavicular head: medial third of clavicle.
Insertion- Mastoid process of temporal bone and lateral half of superior nuchal line of occipital bone.
-
