L4

Question 1

The deltoid muscle crosses the shoulder joint and can do which joint actions?

Answer 1

Flexion, Extension, and Abduction

Question 2

The soleus muscle crosses the ankle joint and can do which joint actions?

Answer 2

Plantarflexion

Question 3

Internal Motors that contribute to movement

Answer 3

Skeletal muscle
-voluntary tissue

Question 4

4 Tissue properties of skeletal muscle?

Answer 4

Irritability (excitability), Contractibility, Extensibility, Elasticity

ICEE

Question 5

Irritability (excitability)

Answer 5

Permits muscles the ability to respond to stimulation

Question 6

Contractibility

Answer 6

Permits muscles the ability to shorten and produce the necessary tension to move the skeletal system

Question 7

Extensibility

Answer 7

Permits muscle the ability to lengthen or stretch past its normal resting length

Question 8

Elasticity

Answer 8

Permits the muscle to return to its resting length after the stretch is removed

Question 9

Functions of Muscle

Answer 9

Produce Movement, Maintain Postures and Positions, Stabilize Joints, support and protect organs, produce tension

Question 10

Muscles can attach:

Answer 10

Directly to the bone by attaching to the periosteum (a thin covering on the outside of bone)
Via a tendon that is fused with the muscle fascia
Via aponeurosis (fibrous connective tissue sheath that remits muscles to increase attachment to bone by widening the area of attachment)

Question 11

Fusiform/ Parallel Muscle

Answer 11

The fiber force is in the same direction as the musculature-muscles are generally long and thin
-greater ROM and greater movement velocity

Question 12

Pennate Muscle

Answer 12

-fibers run diagonally running the length of the muscle (greater cross-sectional area)
-generally short and thick
-utilize Contractibility property to provide greater force production in movements

Question 13

2 Classifications on how muscles cross joints:

Answer 13

Uniarticular and Multiarticular

Question 14

Uniarticular Muscles:

Answer 14

Cross only one joint
Advantage: can contribute every part of it to the intended joint without becoming an opponent to itself
-majority of muscles in human body

Question 15

Multiarticular Muscles

Answer 15

Cross multiple joints in the human body
Advantages: transfer mechanical energy between segments (concentrically contract at one end and eccentrically coontract at the other) -allows muscle to store elastic energy
-redistribute loads placed upon joint (reduce/ absorb or increase stored mechanical energy)

Question 16

Functional Roles of Muscles (4)

Answer 16

Agonist: muscles produce force in same direction as the joint action
Antagonist: muscles produce force opposite to the agonists joint angle
Stabilizer: stabilize a bone at one end so that a movement in an adjacent segment can occur
Neutralizer: contract to eliminate an undesired joint action of another muscle

Question 17

In shoulder abduction:

Answer 17

The deltoid is the agonist because responsible for abduction
The lets are antagonistic because it resists ab
The traps stabilize and hold the scapula
Teres minor neutralizes

Question 18

Torque:

Answer 18

The tendency of a force to produce rotation about a specific axis

Question 19

How is force generated in the muscle

Answer 19

Along the line of action of the force and applied to bone

Question 20

Concentric muscle action

Answer 20

Shortening, least muscle force, muscles overcome external resistance

Question 21

Eccentric muscle action

Answer 21

Lengthening,greatest force production, muscle can’t overcome external force

Question 22

Isometric muscle action

Answer 22

Length stays the same, medium force, no movement

Question 23

Muscle structure properties (4)

Answer 23

Muscle connects to bones via tendon or aponeurosis
Fibers are bundled into fascicles
Fibers contain myofibril strands that run the length of the fiber
The actual contractile unit is the sarcomere

Question 24

3 types of muscle fibers: type 1

Answer 24

Type I: oxidative - slow contraction times und prolonged, low intensity work, fatigue resistant

Question 25

3 types of muscle fibers: type 2a

Answer 25

Intermediate fast twitch and are consistent for lung periods with a burst of force and then fatigue more force than type I

Question 26

3 muscle fiber types: type 2b

Answer 26

Rapid force production but fatigue quickly

Question 27

Sliding filament theory:

Answer 27

Sarcomere contracts, cross bridges are formed between the head of the myosin and a prepared site on the actin filament
Myosin head pulls on actin, filaments move toward each other causing shortening/ contraction

Question 28

3 Components of Mechanical Model of Muscle: Contractile

Answer 28

Converts stimulation of NS into force and reflects shortening of muscle through actin and myosin structures

Question 29

Series Elastic Component: SEC

Answer 29

-all elastic elements in series with the force generating structures of the muscle

Question 30

Parallel elastic component: PEC

Answer 30

-displays elasticity when CC is not producing force

Question 31

Stretch Shortening Cycle
(Preloading of Muscle)

Answer 31

Stretch on muscle increases tension through storage of toenail elastic energy
-following concentric contraction is enhanced by previously stored elastic energy

Question 32

Maximum tension of muscle is reached where

Answer 32

Isometric state
-most cross bridges
-shortens and lengthens hard