Biomechanics: Muscle...types, Actions, Function And Mechanical Levers

Front 1

TRUE or FALSE
No muscle ever works in isolation.

Back 1

TRUE

Front 2

There are over ___ skeletal muscles, providing ___% of body weight.

Back 2

600
40-50%

Front 3

Skeletal muscle is always attached to the _____.

Back 3

Bone

Front 4

Define aggregate muscle action.

Back 4

Muscles work in groups rather than independently to acheive a given joint movement

Front 5

Give an example of a bipennate muscle.

Back 5

Rectus femoris

Front 6

Name an example of a muscle with parallel fiber arrangement.

Back 6

Sartorius

Front 7

The fibers of this type of skeletal muscle are arranged parallel and have large cross section diameters.

They are a hybrid of motion and strength

Back 7

FUSIFORM

Front 8

GIve an example of a muscle with fusiform arrangement

Back 8

Biceps brachii

Front 9

The fibers of this muscle type are arranged obliquely to their tendons in a manner similar to a feather. This arrangement increases the cross sectional area of the muscle, thereby increasing the power (tension)

Back 9

Pennate muscles

Front 10

Give an example of a Unipennate muscle

Back 10

Extensor digitorum

Front 11

Give an example of a Multipennate muscle

Back 11

Deltoid

Front 12

This type of muscle has a broad origin and pointed insertion. It's direction of pull can be varied (versatile)

Back 12

Convergent muscle

Front 13

Give an example of a convergent muscle

Back 13

Pectoralis major

Front 14

This type of muscle has concentric fibers

Back 14

Circular muscles

Front 15

Give an example of a circular muscle

Back 15

Sphincter
Orbicularis oris

Front 16

Define strength

Back 16

The maximum force a muscle can generate for a single maximal effort

The amount of tension a muscle produces

Front 17

Define power

Back 17

Work done over a given period of time (work/time)

A muscle contracting in a very brief amount of time

Front 18

Define torque

Back 18

Muscle force causing rotary movement of a body around an axis

A turning or twisting force

Front 19

It's the tension developed in a muscle as a result of a stimulus

Back 19

Contraction

Front 20

TRUE of FALSE

Muscle contractions can be used to cause, control or prevent joint movement

Back 20

TRUE

Front 21

TRUE or FALSE

All muscle contractions are either isometric or isotonic

Back 21

TRUE

Front 22

Name the two types of isotonic contractions

Back 22

Concentric
Eccentric

Front 23

This type of muscle action is used to stabilize and protect joints

Back 23

Isometric contraction

Front 24

This type of muscle action stimulates mechanoreception thereby decreasing nociception

Back 24

Isometric contraction

Front 25

What is the name for a muscle contraction without appreciable change in the force of contraction..maintains tension under a constant load

Back 25

Isotonic contraction

Front 26

Match CONCENTRIC and ECCENTRIC with the following statements:

1. Shortening contraction, motion
2. Lengthening contraction, stabilization

Back 26

1. Concentric contraction
2. Eccentric contraction

Front 27

This type of muscle action is used to ititiate movement against gravity or resistance

Back 27

Concentric contraction

Front 28

Two muscles are called _______ if their contraction causes movement in the same direction.

Back 28

synergists- a muscle which performs or assists the same joint motion as the agonist

Front 29

Stabalizers are ______ that act to control motion of the prime mover

Back 29

synergists

Front 30

Stabilizers tend to be continuous low-level muscle activity with either ___ or _____ pull.

Back 30

isometric or eccentric

Front 31

When the deltoid contracts to abduct the shoulder, the pectoralis minor, ____ and trapezius muscles stabalize the scapula.

Back 31

rhomboids

Front 32

During wrist joint flexion, the agonist is the wrist ___ and the antagonist is the wrist _____.

Back 32

agonist-flexor
antagonist-extensor

Front 33

When the radio-ulna joint supinates, the supinator is the agonist and the ___ is the antagonist.

Back 33

pronator teres

Front 34

When the elbow flexes, the biceps brachii is the _____ and the triceps brachii is the ________.

Back 34

agonist- biceps
antagonist- triceps

Front 35

When the shoulder adducts, the latissimaus dorsi is the ____ and the middle deltoid is the _____.

Back 35

lat dorsi-agonist
middle deltoid- antagonist

Front 36

As the spine rotates, the agonists are the ___ obliques and the antagonists are the ___ obliques.

Back 36

agonist- internal obliques
antagonist- external

Front 37

As the hip extends, the agonist is the ______ and the antagonist is the ____.

Back 37

agonist- gluteus maximus
antagonist- iliopsoas

Front 38

As the knee extends, the hamstrings are the ______ and the quadriceps are the ______.

Back 38

quadriceps- antagonist
hamstrings - agonist

Front 39

What is a lever?

Back 39

a rigid bar that moves on a fixed point- bones of the skeleton

Front 40

The joints of the body are ____, a fixed point of leverage.

Back 40

fulcrum

Front 41

_____ is defined as the force applied to move a resistance.

Back 41

Effort - the tension of the muscles

Front 42

The ____ is the resistance to be moved.

Back 42

load

Front 43

The lever converts force into ____.

Back 43

torque

Front 44

____, ___ and external physical contacts are the forces involved with musculoskeletal levers.

Back 44

muscle, gravity

Front 45

A power lever, or ____ ____ can lift heavy loads because the load is close to the fulcrum, the effort is applied far from the fulcrum and a small effort can be used to move a large load.

Back 45

mechanical advantage lever

Front 46

Mechanical disadvantage levers allow a load to move rapidly through a large range of motion and are called ____ levers.

Back 46

speed

Front 47

Musculoskeletal levers allow a muscle to move a heavier load or to move a load faster or farther that it otherwise could. Is it true, then that muscles don't need as much strength ?

Back 47

Yes!

Front 48

The Atlanto-occipital joint lies between the posterior cervical muscles and the weight of the forehead and face. Is this an example of 1st, 2nd or 3rd class lever?

Back 48

1st class, where the fulcrum lies between the the effort and the load.

Front 49

The load lies between the fulcrum and the effort, as in the plantar flexion of the feet. Which class of lever is this?

Back 49

second class- great strength, less speed and range of motion

Front 50

Most levers in the body are _____ class levers, where the effort is applied at a point between the load and the fulcrum.

Back 50

third

Front 51

The force is lost (not strong) with ___ levers and gained (strong) with ____ levers.

Back 51

lost- mechanical disadvantage, speed
gained- mechanical advantage, power

Front 52

Muscle spindle receptors consist of ___ ___ fibers which are modified muscle fibers enclosed in a capsule within ____ ____ fibers.

Back 52

Intrafusal muscle fibers
Extrafusal muscle fibers

Front 53

__ __ __ are proprioceptive encapsulated nerve endings located at the junction of tendon and muscle.

Back 53

Golgi tendon organs or GTO

Front 54

GTO's detect the ____ of muscle contraction, ___ applied to the tendon, and prevents contracting muscle from applying excessive tension to the ____.

Back 54

GTO's detect the ORCE of muscle contraction, TENSION applied to the tendon, and prevents contracting muscle from applying excessive tension to the TENDON.

GTO stimulation produces sudden relaxation of the muscles.

Front 55

Stimulated only by (choose light or intense) stretch, GTO's enter the spinal cord and synapse with ____ ____. (think general)

Back 55

inhibitory interneurons

Front 56

Stimulated GTO's send sensory neurons to synapse with inhibitory interneurons, which synapse with alpha motor neurons. Why is this important?

Back 56

Inhibitory neurotransmitters are released which inhibit the alpha motor neurons that innervate the extrafusal muscle the GTO is attached to. The muscle relaxes, protecting the tendon and muscle from damage.

Front 57

GTOs can cause _____ and ______ response.

Back 57

Dynamic response: sudden increase in muscle tension causes a decrease in muscle tone via involuntary muscle relaxation
Static response: a sustained or gradual increase in muscle tension causes a decrease in muscle tone

Front 58

Clinically, GTOs inhibit a muscles synergistic stabilizers while facilitating its _____.

Back 58

antagonist
GTO's reflexively inhibit agonists at the end range of joint motion.
i.e. Facilitate the hamstring and relax the quadriceps.

Front 59

Nerve location: A muscle spindle is ___ whereas a GTO is ____.

Back 59

spindle=intrafusal
GTO extrafusal

Front 60

A ___ provides sensory and motor innervation.

Back 60

muscle spindle
A GTO provides only sensory

Front 61

Nerve function: A ___ provides involuntary muscular contraction and a ____ provides involuntary muscular relaxation.

Back 61

muscle spindle contracts and a GTO relaxes

Front 62

____ ____ receptors are encapsulated and free nerve endings located in and around synovial joint capsules.

Back 62

Joint kinesthetic receptors

Front 63

What are three types of joint kinesthetic receptors?

Back 63

Pacinian corpuscles, ruffini corpuscles and free nerve endings

Front 64

Located in CT and ____ joint capsules, Pacinian corpuscles respond to rapid pressure changes, ___, acceleration and _____ of the joint movement.

Back 64

Located in CT and synovial joint capsules, Pacinian corpuscles respond to rapid pressure changes, stretch, acceleration and deceleration of the joint movement.

Front 65

Located in synovial capsules and ___, ______ corpuscles respond to deep rapid and sustained pressure, lateral stretch, changes in joint angle.

Back 65

Ruffini is in ligaments too. The ligament receptors adjust muscle tone

Front 66

Free nerve endings are located in ___ and respond to rapid and sustained ___.

Back 66

FOUND IN MOST BODY TISSUES, THEY RESPOND TO RAPID AND SUSTAINED PRESSURE. OOPS, THAT WASN'T SUPPOSED TO BE IN CAPS...!

Front 67

Proprioceptors affect the tone via three reflexes that tell us about the integrity of the CNS. What are they?

Back 67

Quick stretch reflex
Reciprocal inhibition
Autogenic inhibition

Front 68

Quick stretch reflex is in response to which type of innervation?

Back 68

muscle spindles- producing contraction of muscles being stretched.
Sequence- 1. muscle is stretches 2. muscle spindle afferent to spinal cord 3. monosynaptic 4. alpha motor neuron stimulates agonist

Front 69

The reciprocal inhibition reflex response is from which nerve type? What does it do?

Back 69

muscle spindles inhibit the muscle opposite the contracted muscle. This induces relaxation of an antagonist so the agonist can contract and cause joint movement.

Front 70

Describe the sequence of events of reciprocal inhibition.

Back 70

1. Muscle is stretched. 2. Muscle spindle afferent to spinal cord. 3 inhibitory interneuron relaxes antagonist.

Front 71

Autogenic inhibition is a reflex response from ____. This inhibitory action is in response to a muscle with too much shortening or lengthening ___.

Back 71

GTOs sense tension

Front 72

Post isometric relaxation, muscle energy technique and strain-counterstrain are manipulative techniques based on which reflexes?

Back 72

quick stretch, autogenic inhibition and reciprocal inhibition

Front 73

Deep tendon reflexes (DTR) contribute to determining if there is a lower or upper _____ neuron lesion.

Back 73

motor

Front 74

The direction of movement produced by the contracting muscle is called?

Back 74

Line of pull
-the pull of a muscle from origin to insertion
-may change during joint motion
-fxn of muscle's attachment, plane of joint motion, distance from joint's axis of rotation

Front 75

This muscle is primarily a flexor of the humerus but also adducts the humerus because of its line of pull in certain arm positions.

Back 75

Pectoralis major

Front 76

What results from muscle's line of pull being altered from its original position?

Give a common example.

Back 76

Muscle will be inefficient, work harder and have more strain put on it. This can lead to muscle weakness, hypertonicity, trigger points, aberrant sensory input which can result in muscle imbalance & joint dysfunction.

Chronic forward head posture

Front 77

Define the angle of pull.

Back 77

Angle of pull = the angle between the line of pull of the muscle and the bone on which it inserts

Front 78

A ___ component of the angle is always perpendicular to the lever (attachment) & causes rotational movement at the joint axis.

A ____ component of the angle is always parallel to the lever & causes non-rotational movement at the joint axis.

Back 78

A VERTICAL component of the angle is always perpendicular to the lever (attachment) & causes rotational movement at the joint axis.

A HORIZONTAL component of the angle is always parallel to the lever & causes non-rotational movement at the joint axis.

Front 79

Name 7 things upon which muscle action depends.

Back 79

No. of motor units activated
Type of motor unit activated
Size of the muscles
Initial muscle lengths
Angle of the muscle & joint
Speed of muscle contraction
Type of muscle fibers

Front 80

Fill in the blank:
A muscle produces a contraction (__) which causes rotational movement at a joint (__) by pulling on its insertion (___) at a constantly changing angle (___) which affects the force applied to that body segment (___).

Back 80

A muscle produces a contraction (TENSION) which causes rotational movement at a joint (TORQUE) by pulling on its insertion (LINE OF PULL) at a constantly changing angle (ANGLE OF PULL) which affects the force applied to that body segment (JOINT).

Front 81

Reverse-Action of Biceps Muscle:

In Biceps curls, insertion on the ___ is least movable; insertion on the ___ is most movable.

In Chin ups, Insertion on ___ is least movable; insertion on ___ is most movable.

Back 81

In Biceps curls, insertion on the SCAPULA is least movable; insertion on the RADIUS is most movable.

In Chin ups, Insertion on RADIUS is least movable; insertion on SCAPULA is most movable.

Front 82

What length of muscle fibers = large range of motion? What type of muscles have these fibers?

Back 82

Long fibers = Large range of motion

Ex) Parallel & Fusiform muscles.

Front 83

Many muscle fibers = ?
What types of muscles have many fibers?

Back 83

Many muscle fibers=great tension.

Ex) Convergent, Unipennate, Bipennate, Multipennate muscles

Front 84

Match the term with its definition.
Irritability, Contractility, Extensibility, Elasticity.

-Ability of muscle to return to its original length
--Ability of muscle to be passively stretched beyond its normal resting length
-Property of muscle being sensitive or responsive to chemical, electrical or mechanical stimuli
-Ability of muscle to contract & develop tension agst resistance when stimulated

Back 84

Elasticity- Ability of muscle to return to its original length
Extensibility- Ability of muscle to be passively stretched beyond its normal resting length
Irritability- Property of muscle being sensitive or responsive to chemical, electrical or mechanical stimuli
Contractility- Ability of muscle to contract & develop tension agst resistance when stimulated

Front 85

T/F
A muscle may be innervated by more than one nerve.

A particular nerve can innervate only one muscle.

Two or more muscles may share a common tendon.

Back 85

T/F
TRUE. A muscle may be innervated by more than one nerve.

FALSE. A particular nerve can innervate More Than One muscle.

TRUE. Two or more muscles may share a common tendon.

Front 86

Muscles act as ____ when they assume the major responsibility for producing a specific movement.

Back 86

Muscles act as PRIME MOVERS/ AGONISTS when they assume the major responsibility for producing a specific movement.

Front 87

Muscles act as _____ when they oppose or reverse the movement of a prime mover.

Back 87

Muscles act as ANTAGONISTS when they oppose or reverse the movement of a prime mover.

Front 88

When a prime mover is active, what is the antagonist doing?

Back 88

Its either relaxed allowing movement of the joint. Or it can partially contract to provide some resistance to slow/stop the action- regulating the prime mover.