Exam 1: The Musculoskeletal System - Muscle

Question 1

Muscle Fun Facts

True or False
-You have all the muscle fibers you will ever have at birth.

Answer 1

True! But once damaged they can’t be replaced.

Question 2

Muscle Fun Facts

The strongest muscle of the body is the _______ muscle used for chewing!

Answer 2

masseter

Question 3

Muscle Fun Facts

• If all your muscles could pull in one direction you could create a force of 25 tons!
• It takes 17 muscles in your face to smile : ) but takes 43 muscles to frown : (

Answer 3

Yuh

Question 4

Muscle Fun Facts

The ______ is the only muscle in the body that is attached at only at one end.

Answer 4

tongue

Question 5

____’ Law: Used in anatomy to describe how soft tissue models along imposed demands.

Answer 5

Davis’ Law

Question 6

_________ refers to an increase in the SIZE of cells and subsequently, an increase in size of involved organs/tissue.

Answer 6

Hypertrophy

Question 7

__________ refers to an increase in the NUMBER of cells in an organ or tissue and subsequently, an increase in size of the involved organ or tissue.

Answer 7

Hyperplasia

Question 8

Types of Contraction


• Know these basics
  1) _______: muscle remains at equal length
  2) ________: muscle shortens
  3) ________: muscle lengthens

Answer 8

1) Isometric
2) Concentric
3) Eccentric

Question 9

Types of Contraction


*Other terms

• Iso_____:
• Muscle maintains equal tension while length changes.
• Lifting object at a constant speed.
• Iso______:
• Equal or same motion.
• Special equipment allows for same speed throughout ROM despite amount of force.

Answer 9

Isotonic

Isokinetic

Question 10

Tendon vs Ligament

• Tendon serves as an anchor for the ______ and connects it to ____.
• Ligament connects _____ to _____.
• When a person suffers a traumatic injury, ligaments and tendons may be pulled, sprained/strained or even torn completely.

Answer 10

muscle, bone

bone to bone

Question 11

Sprain vs Strain

• Sprain involves the stretching or tearing of a _______.
• Strains involve the stretching or tearing of a ___________ unit.

Answer 11

ligament (connects bone to bone)

musculo-tendinous (s”T”rain = “T”endon)

Question 12

Muscular Attachments

Origin and Insertion

• Origin = usually more ________.
• Insertion = usually more _____.

Answer 12

proximal

distal

Question 13

Structural Classification of Muscles by Fiber Arrangement

• _________ muscle: long muscle with fibers in parallel to its long axis.
• Example: Sartorius

Answer 13

Longitudinal

Question 14

Structural Classification of Muscles by Fiber Arrangement

*_______/Quadrilateral muscle: four sided and usually flat.
Consist of parallel fibers.
-Example: Rhomboids

Answer 14

Quadrate

Question 15

Structural Classification of Muscles by Fiber Arrangement

• ________ or Fan-Shaped: fibers radiate from a narrow attachment at one end to a broad attachment at the other.
• Example: Pectoralis major

Answer 15

Triangular

Question 16

Structural Classification of Muscles by Fiber Arrangement

• ________/Spindle-Shaped: rounded muscle that tapers at either end.
• Example: Brachioradialis

Answer 16

Fusiform

Question 17

Structural Classification of Muscles by Fiber Arrangement

• _______: a series of short, parallel, feather like fibers extends diagonally from the side of a long tendon.
• Example: Tibialis posterior

Answer 17

Pennate

Question 18

Structural Classification of Muscles by Fiber Arrangement

_________: A long central tendon with fibers extending diagonally in pairs from either side of the tendon.
-Example: Rectus femoris.

Answer 18

Bipennate

Question 19

Structural Classification of Muscles by Fiber Arrangement

• __________: Several tendons are present, with fibers running diagonally between them.
• Example: Middle deltoid

Answer 19

Multipennate

Question 20

• _______ muscles are the most powerful of the body
• Common angle with tendon
• Contain more muscle fibers

Answer 20

Pennate

Question 21

Key Concept

• The basis for all muscle function is the ability of muscular tissue to ______.
• The theory of muscle contraction is known as the _________ ________ theory.

Answer 21

contract

Sliding Filament Theory
-Myosin (thick) filaments attach and pull Actin (thin) forming crossbridges

Question 22

Can skeletal muscle apply force via pulling only, pushing only, or both?

Answer 22

Muscles can only generate force while SHORTENING, they cannot exert force via push, ONLY pull!

Question 23

Skeletal Muscle Function – 
Line of Pull

• Line of Pull: angle between muscle ______ and bone on which it inserts.
• Movement that the contracting muscle produces is determined by two factors:
  1) Type of _____ that is spans.
  2) The relation of the muscle’s line of ____ to the joint.

Answer 23

insertion

joint

pull

Question 24

Skeletal Muscle Function – 
Line of Pull

*It is common to classify muscles in relation to their line of pull.

• Muscles whose line of pull produce flexion are called?
• ______
• Muscles whose line of pull produce extension are called?
• _______
• Muscles whose line of pull produce abduction, adduction and rotation?
• _______

*Some controversy with classification (EMG is accurate)

Answer 24

Flexors

Extensors

Rotators

Question 25

Skeletal Muscle Function – 
Line of Pull *Knowing the general location of a muscle with respect to the joint axis – (ant., post., lat., med.) and knowing the line of pull of the muscle is important for deducing possible muscle participation during a body movement.

Answer 25

Yuh

Question 26

Skeletal Muscle Function – 
Length-Tension Relationship * There is an optimal length at which a muscle exerts maximal _______. * This optimal relationship is dependent upon the muscle’s structure and function. * General rule for facilitating the optimal length-tension relationship is to position the muscle slightly [greater than/less than] its resting length. * Longer tendons generate higher levels of stored elasticity than shorter tendons.

Answer 26

tension greater than

Question 27

Skeletal Muscle Function – 
Force-Velocity Relationship * As the speed of muscle contraction increases, the force it is able to exert ________. * The velocity of contraction is max when load is 0. * The load is max when the velocity is 0. 1) If activity requires large forces, then a slow or fast muscle contraction should be expected? * If fast limb velocity is needed, then a small or large amount of contractile force should be expected?

Answer 27

decreases 1) Slow 2) Small

Question 28

Skeletal Muscle Function – 
Stretch-Shortening Cycle * Both muscle and tendon possess ______ properties. - When they are stretched they store _______, and will release this _______ upon return to their original length. *When a _________ contraction is preceded by an active stretch, the elastic energy stored during the stretch is available for use in the contractile phase. (countermovement jump).

Answer 28

elastic energy, energy concentric

Question 29

Roles of Muscles - Agonists * Agonists are [directly/indirectly] responsible for producing a movement. - Prime movers - large impact on movement - Assistant movers – only help when needed

Answer 29

directly

Question 30

Roles of Muscles - Antagonists * Antagonists have an effect _______ to that of movers, or agonists. - Check ballistic movements - First, antagonists must _____ to permit movement. - Second, antagonists act as a _____ at completion of movement.

Answer 30

opposite relax brake

Question 31

Roles of Muscles - Synergists * Synergists possess '________', supporting and neutralizing properties. - A stabilizing example is when the rhomboids stabilize the scapula against the pull of the teres major. * Neutralizers prevent _______ action. - As an example, if a muscle both flexes and internally rotates, but only flexion is desired in the movement, what must happen? - An external rotator(s) contracts to prevent the internal rotation action of the mover – and in this case acts as a neutralizer.

Answer 31

stabilizing undesired

Question 32

Cocontraction *The simultaneous cocontraction of _______/movers and _________ does occur. * Cocontraction is most often associated with _________ in dynamic, unstable situations. - Abdominals and low back to maintain posture in unstable situations.

Answer 32

agonists, antagonists stabilization

Question 33

Bi-Articular Muscles *Bi-articular muscles pass over and act on ____ joints Example: Hamstrings *Bi-articular muscles have two different patterns of action, described as ________ and __________ movements.

Answer 33

two concurrent, countercurrent

Question 34

Bi-Articular Muscles * Concurrent Movements - Simultaneous ______ or _______ of the hip and knee joints. - No net change in length of either muscle. * Countercurrent Movements - One muscle shortens at both joints as its’ antagonist _________ correspondingly and thereby gains _______ at both ends.

Answer 34

flexion, extension lengthens, tension