Form and Action at joints

Question 1

How does the skeletal muscle cause movement at synovial joints

Answer 1

Attaches to bone
Muscle structure
Type of contraction
Where it crosses a joint

Question 2

Level arrangement…

Answer 2

determines function

Question 3

Example of first class lever

Answer 3

See saw, scissors

Question 3

The anatomical levers are

Answer 3

Bone
Joint
Muscle contraction
Weight of what is being moved/load

Question 3

Second lever class function

Answer 3

-Effective at overcoming heavy loads
-Load between fulcrum and force

Question 4

The classes of levers

Answer 4

First second third

Question 5

First lever class function

Answer 5

-Stabilises joint positon
- Fulcrum between force and load

Question 6

Example of second class lever

Answer 6

Wheelbarrow, bottle opener

Question 7

Third lever class function

Answer 7

-Large range of movement, speed
-Force between fulcrum and load

Question 8

Example of third class lever

Answer 8

tweezers, fishing rod

Question 9

Muscle form determines function depending on

Answer 9

• Length of muscle fibres
• Number of muscle fibres
• Arrangement of muscle fibres

Question 10

Length of muscle fibres explain

Answer 10

-Fibres can shorten up to 50% of resting length
-If large ROM required - long muscle fibres

Question 11

Fibres can shorten up to what percentage of resting length

Answer 11

50%

Question 12

If a larger ROM is required,

Answer 12

the longer the muscle fibres will be

Question 13

Number of muscle fibres explain

Answer 13

• Tension is directly proportional to the cross sectional area
• Greater number of fibres = greater cross sectional area and greater tension

Question 14

Two types of muscle arrangement

Answer 14

Parallel and pennate

Question 15

Explain the parallel muscle arrangement

Answer 15

• Fibres are arranged vertically between muscle tendons/attachments
• Smaller cross sectional area, greater shortening

Question 16

Explain pennate muscle arrangement

Answer 16

• Fibres are arrange obliquely between muscle tendons/attachments
  -Greater cross sectional area, lesser shortening

Question 17

Concentric

Answer 17

-Muscle is active, develops tension
-Tension is greater than load
-Muscle shortens
-Change in joint position

Question 17

Muscles can contract in three ways which are

Answer 17

Concentric
Eccentric
Isometric

Question 18

Eccentric

Answer 18

• Muscle is active, develops tension
  -Tension is lesser than load
  -Muscle elongates, pull in opposite direction by another muscle/gravity
  -Change in joint position

Question 19

Agonist

Answer 19

creates movement

Question 20

Isometric

Answer 20

-Muscle is active, develops tension
-Tension does not outweigh load
-No change in length of muscle
-No change in joint position

Question 21

Types of muscle roles at a joint

Answer 21

Agonist
Antagonist
Stabiliser
Neutraliser

Question 22

Antagonist

Answer 22

opposes/controls movement

Question 23

Stabiliser

Answer 23

holds joint still

Question 24

neutraliser

Answer 24

stops unwanted movement

Question 25

Agonists acts...

Answer 25

concentrically to create a movement at a joint

Question 26

Antagonist acts...

Answer 26

eccentrically to oppose and control the movement

Question 27

Stabilisers holds..

Answer 27

a joint still and prevents the movement of a joint

Question 28

When holding a heavy book, what happens with the biceps brachii

Answer 28

The role of the biceps brachii is the stabiliser, in action it is isometric. There is no change in the length of the biceps brachii and no movement at elbow joint

Question 29

Neutralisers eliminates...

Answer 29

an unwanted movement caused by another muscle

Question 30

Concentric actions of muscles

Answer 30

Anterior - flexion Lateral - abduction Medial - adduction Posterior - extension

Question 31

What influences the movements a muscle produces at a joint

Answer 31

Its structure, location and type of contraction

Question 32

Muscle action and role changes...

Answer 32

depending on the movement