Chapter 5 (Muscular System)

Question 1

What are muscle names based off of?

Answer 1

1. Location
2. Shape
3. Action
4. # of heads or divisions
5. Attachments= origin/insertion
6. Direction of fibers
7. Size

Question 2

When a muscle contracts it knows no direction: it simply ____?

Answer 2

shortens

Question 3

What is the more movable bone?

Answer 3

Insertion (most distal) which moves toward the origin

Question 4

What is the more stable bone?

Answer 4

Origin (most proximal)

Question 5

What is the reversal of a muscle action ?

Answer 5

When the origin moves towards the insertion

Question 6

Long and thin, fibers run the entire length of the muscle

Answer 6

Strap muscle (parallel)

Question 7

Spindle shape- wide mouth tapered ends (muscle)

Answer 7

Fusiform muscle (parallel)

Question 8

Four sided, flat (muscle)

Answer 8

Rhomboidal muscle (parallel)

Question 9

Flat, fan shaped, fibers radiating from a narrow attachment

Answer 9

Triangular muscle (parallel)

Question 10

looks like one side of a feather (muscle)

Answer 10

Unipennate (oblique)

Question 11

pattern common feather (muscle)

Answer 11

Bipennate (oblique)

Question 12

Many tendons (muscle)

Answer 12

Multipennate (oblique)

Question 13

What is normal resting length?

Answer 13

1. when the length is unstimulated

2. When there are no forces or stresses on it

Question 14

What are the four functional characteristics of muscle ?

Answer 14

1. Irritability
2. Contractility
3. Extensibility
4. Elasticity

Question 15

Ability to respond to a stimulus

- Contracts when stimulated, motor nerve or electric current

Answer 15

Irritability

Question 16

Ability to shorten or contract

• Produces tension between ends
• The muscle shortens, stays the same, or lengthens

Answer 16

Contractile

Question 17

Ability of a muscle to stretch or lengthen when force is applied

Answer 17

Extensibility

Question 18

Ability to recoil or return to normal resting length when stretching or shortening force is removed

Answer 18

Elasticity

Question 19

What is tension?

Answer 19

Force built up within the muscle

Question 20

What does it mean to shorten?

Answer 20

muscle shortens 1/2 its normal resting length

Question 21

What is excursion?

Answer 21

Distance from max elongation to max shortening
(From the shortened to lengthened; 3”-9” = excursion)
Shortened = 3”
Normal = 6”
Stretched = 9”

Question 22

When a muscle reaches a point where it cannot shorten any farther
- Occurs to the agonist

Answer 22

Active insufficiency

Question 23

When a muscle cannot be elongated any farther without damage to the fibers
- Occurs to the antagonist, opposite the agonist

Answer 23

Passive insufficiency

Question 24

Example of Active insufficiency…

Answer 24

Hamstrings which are a two joint muscle (extend the hip and flexes the knee). Can preform either motion but not simultaneously. If you flex the knee while hip is extended it cannot complete full range because muscle is at maximum contraction.

Question 25

Example of Passive insufficiency...

Answer 25

hamstrings -muscle can be stretched of two joints but not simultaneously. sitting with knee extended then try to flex hip. hamstring is to tight it has already been stretched to maximum capacity.

Question 26

Agonist usually becomes actively insufficient (cannot contract any farther) before the antagonist becomes passively insufficient (cannot be stretched farther)

Answer 26

Stretching

Question 27

What are the 3 types of muscle contractions?

Answer 27

1. Isometric 2. Isotonic 3. Isokinetic

Question 28

When a muscle contracts, producing force without changing the length of the muscle (joint angle does not change)

Answer 28

isometric | Ex. plank position

Question 29

Muscle contracts, changing the muscle length and the joint angle. Can be concentric or eccentric

Answer 29

Isotonic

Question 30

Muscles shorten and the muscle attachments move towards each other. Usually occurs against gravity direction (raising motion)

Answer 30

Concentric | Ex. - biceps muscle bringing up the barbell.

Question 31

Describe eccentric

Answer 31

Muscles lengthen and the muscle attachments move away from each other Usually occurs with gravity (lowering motion) Ex. biceps muscles as a barbell is lowered.

Question 32

What are roles of muscle ?

Answer 32

1. agonist 2. Antagonist 3. Cocontraction 4. Stabilizer

Question 33

Muscle or muscle groups that cause the motion

Answer 33

Agonist | Ex. During elbow flexion bicep is the agonist and pronator teres is the assisting mover

Question 34

Muscle that performs opposite motion of agonist

Answer 34

Antagonist | Ex. During elbow flexion bicep is agonist and tricep is the antagonist.

Question 35

When agonist and antagonist contract at same time. Occurs when there is a need for accuracy.

Answer 35

Cocontraction

Question 36

Group which stabilizes the part to allow the agonist to perform more effectively; sometimes referred to as a fixator

Answer 36

Stabilizer | Ex. When doing a push up abdominal muscle are the stabilizes

Question 37

Muscles only have one direction of pull. It is usually a diagonal line of pull.

Answer 37

Angle of pull

Question 38

What are 3 types of angle of pull?

Answer 38

1. Vertical 2. Horizontal 3. Diagonal

Question 39

Elevating or depressing the scapula is an example of what angle of pull?

Answer 39

Vertical pull

Question 40

Retract or protract the scapula is an example of what angle of pull?

Answer 40

Horizontal pull

Question 41

What type of pull causes motion in both planes?

Answer 41

Diagonal pull

Question 42

Position in which the muscle shortens without having to work against the effects of gravity. Done in horizontal plane.

Answer 42

Gravity-eliminated exercise

Question 43

Describe a closed-kinetic chain

Answer 43

Distal segment is fixed (closed) and the proximal segment moves. Ex. Rising from a chair; (your knees extend causing your hip and ankles to move as well)

Question 44

Describe an open-kinetic chain

Answer 44

Distal segment is free to move and the proximal end remains stationary. Ex. being seated and extending knee; (your knee, hip, and ankle would not move)