S&F of muscular and fascial systems

Question 1

Approximately how many muscles are there in the human body, and how much body weight do they comprise of

Answer 1

There are approximately 680 muscles in the human body, that comprise 40-50% of an individual’s body weight

Question 2

What are the 3 types of muscle tissue and what is their role

Answer 2

Smooth - muscles found in various internal organs (e.g. blood vessels)
Cardiac - heart muscles
Skeletal - muscles that cause joint movement

Question 3

What is the main function of skeletal muscles

Answer 3

Skeletal muscles cause joint movement, or the muscle contractions produce the force that cause joint movement

Question 4

What are some other functions of skeletal muscles

Answer 4

Protection to underlying structures
Function as a shock absorber
Provide dynamic stability to joints
Maintain posture and provide support
Produce a major portion of total body heat

Question 5

3 characteristics of skeletal muscles

Answer 5

Extensibility
Elasticity
Contractility - the ability to develop tension (force) when stimulated

Question 6

Sarcolemma

Answer 6

A thin transparent extensible cell (plasma) membrane that covers each
muscle fibre

Question 7

Epimysium

Answer 7

It is a layer of dense irregular connective tissue which surrounds the entire muscle and protects muscles from friction against other muscles and bones.

Question 8

Endomysium

Answer 8

A thin sleeve of fibrous connective tissue that encloses the individual muscle
fibers and connects muscle fibers to one another
i.e. between fibres

Question 9

Perimysium

Answer 9

Perimysium is a sheath of dense irregular connective tissue that groups muscle fibres into bundles or fascicles.

Question 10

How is the structure of the skeletal muscle organised

Answer 10

The muscle belly is made up of muscle fascicles. Between these is the perimysium.
In each muscle fascicle are many muscle fibres. The endomysium connects these muscle fibres
A single muscle fibre contains a sarcolemma, which has many myofibrils

Question 11

List the key aspects of a skeletal muscle

Answer 11

Epimysium
Fascicles
Endomysium
Perimysium
Muscle fibre
Sarcolemma
Myofibril

Question 12

Sarcomere

Answer 12

The segment between the neighbouring Z-lines. This is the basic contractile unit of the muscle

Question 13

Z band

Answer 13

Defines the boundary between 2 sarcomeres in a muscle fibre

Question 14

Sarcomeres are located between the _________ along the length of a _________

Answer 14

Sarcomeres are located between the Z lines along the length of a myofibril

Question 15

Each sarcomere contains

Answer 15

I bands
A bands
H zone
M line

Question 16

I bands

Answer 16

I bands - light band located at each end of a sarcomeres length - contains only actin (I is a thin letter I bands only contain thin actin filaments)

Question 17

A bands

Answer 17

A bands - dark band in the mid point of the sarcomere - contains the full lengths of the myosin filaments and the regions where myosin and actin overlap
A band - ALL of the myosin

Question 18

H zone

Answer 18

The lighter area within the A-bans, consists of only myosin (no overlap with actin)

Question 19

M line

Answer 19

The M line within the H zone is the area where adjacent myosin filaments attach to one another

Question 20

Tendons:
Where are they located?
What do they do?
What are they composed of?

Answer 20

Tendons are located at either end of the muscle belly
Most tendons attach muscle to bone, some attach muscle to other tendons, fascia, ligaments or skin
Tendons are composed of dense fibrous connective tissue that is cordlike in appearance

Question 21

Tendon sheath

Answer 21

Where tendons cross bony areas, they are covered with a tendon sheath to protect them from wear and tear from bony structures they cross. It functions to reduce friction between the tendons and bony structures they cross

Question 22

Function of tendons

Answer 22

Transmit the force generated by contracting muscles to bones

Question 23

Origin and insertion of tendons

Answer 23

Origin - proximal attachment of a muscle or the part that attaches closest to the midline or centre of the body
Insertion - distal attachment of a muscle or the part that attaches farthest from the midline or centre of the body

Question 24

What can muscle contractions be defined according to?

Answer 24

Whether there is a change in joint position associated with the muscle action. If there is a change in joint
position, the muscle action can be further defined by whether the muscle creating
tension is shortening or elongating.

Question 25

Isometric contraction

Answer 25

Tension is developed within the muscle, but there is no change in joint position

Question 26

Isotonic contraction

Answer 26

Tension is causing a change in joint position, or controlling a change
in joint position (concentric or eccentric)

Question 27

Concentric contraction

Answer 27

The muscle tension is causing a change in joint position
During concentric muscle actions, the muscle producing the tension
shortens

Question 28

Agonist (prime mover)

Answer 28

The main muscle(s) active maintaining, controlling, or producing a movement
(e.g. the biceps muscles are ALWAYS the agonist during the performance of a bicep curl
exercise)
* The agonist can be acting concentrically, eccentrically, or isometrically

Question 29

Antagonist

Answer 29

The muscle(s) that produce the movement opposite of the agonist. The
antagonist is located on the opposite side of the joint from the agonist. The
antagonist is usually inactive/less active than the agonist during the movement
or portion/phase of the movement (e.g. the triceps muscles are the antagonist
during the performance of a bicep curl exercise)

Question 30

Synergist

Answer 30

Any muscles that function to assist the agonist, but that are not considered a
prime mover for the movement or portion/phase of a movement.
May have the same action as the agonist, but considered a synergist due to the small size, angle of pull

Question 31

Fixator

Answer 31

Muscles that act during the movement or portion/phase of the movement to
hold/fixate/stabilize a bone while a prime mover performs its function (e.g.
During a biceps curl, muscles acting on the scapula and glenohumeral joint
stabilize the shoulder complex and humerus so the biceps brachii can more
effectively perform the bicep curl exercise

Question 32

Dense connective tissue

Answer 32

A continuous sheet of fibrous membrane located beneath the skin and around muscles and organs

Question 33

Superficial fasica

Answer 33

Immediately deep to the skin, covers the entire body