Musculoskeletal system: form and action at joints

Question 1

explain a class 1 lever

Answer 1

fulcrum is between force and load
stabilizes joint position
-a see-saw
-neck extension at atlanto-occipital joint

Question 2

explain a class 2 lever

Answer 2

load is between fulcrum and force
effective at overcoming heavy loads
-a wheelbarrow
-plantar flexion at the ankle joint

Question 3

explain a class 3 lever

Answer 3

force is between fulcrum and load
large range of movement and speed
-tweezers
-flexion at the elbow jointf

Question 4

3 factors that determine muscle function

Answer 4

1. length of muscle fibers
2. number of muscle fibres
3. arrangement of fibers

Question 5

3 types of muscle action

Answer 5

1. concentric
2. eccentric
3. isometric

Question 6

explain concentric movement

Answer 6

muscle shortens and the angle decreases
tension is greater than the load
change in joint position, the muscle is active and develops tension

Question 7

explain eccentric movement

Answer 7

muscle elongates by being pulled by another muscle or gravity in the opposite direction and the angle increases
tension is lesser than the load
change in joint position, the muscle is active and develops tension

Question 8

explain isometric movement

Answer 8

there is no change in joint position or length of muscle
muscles are active and develops tension BUT tension is equal to the load

Question 9

4 roles of the muscles

Answer 9

1. agonist: creates movement
2. antagonist: opposes or controls movement
3. stabilizer: holds joint still
4. neutralizer: stops unwanted movement

Question 10

explain agonist and antagonist roles

Answer 10

agonist: acts concentrically to create movement at the joint
eg: flexion at the elbow
- biceps brachii shortens
antagonist: acts eccentrically to oppose and control the movement
- triceps brachii lengthens

Question 11

explain stabilizers roles

Answer 11

holds the joint still and prevents movement at joint
eg: holding a heavy book
- biceps brachii acts as a stabilizer and is isometric

Question 12

explain neutralizers roles

Answer 12

eliminates an unwanted movement caused by another muscle
eg: trying to drink from a glass
-biceps brachii can flex the elbow and supinate however when drinking from a glass you dont want the arm to supinate
-pronator muscles in the forearm acts as a neutralizer

Question 13

bicep brachii - origin

Answer 13

scapula

Question 14

bicep brachii - insertion

Answer 14

radial tuberosity

Question 15

bicep brachii - movement

Answer 15

shoulder: flexion
elbow: flexion
radioulnar joints: supination

Question 16

triceps brachii - origin

Answer 16

scapula and humerus

Question 17

triceps brachii - insertion

Answer 17

olecranon process of ulna

Question 18

triceps brachii - movement

Answer 18

shoulder: extension
elbow: extension

Question 19

deltoid - origin

Answer 19

scapula and clavicle

Question 20

deltoid - insertion

Answer 20

deltoid tuberosity

Question 21

deltoid - movement

Answer 21

shoulder movement
- flexion: anterior fibers
- abduction: lateral fibers
- extensions: posterior fibers

Question 22

iliopsoas - the 2 sections

Answer 22

iliacus and psoas major

Question 23

iliopsoas - origin

Answer 23

iliacus - iliac fossa
psoas major - lumbar vertebrae

Question 24

iliopsoas - insertion

Answer 24

femur

Question 25

iliopsoas - movement

Answer 25

hip - flexion

Question 26

gluteus maximus - origin

Answer 26

ilium and sacrum

Question 27

gluteus maximus - insertion

Answer 27

femur

Question 28

gluteus maximus - movement

Answer 28

hip - extension

Question 29

quadriceps femoris - the 4 sections

Answer 29

1. rectus femoris the vastus muscles 2. lateralis 3. intermedius 4. medialis

Question 30

quadriceps femoris - origin

Answer 30

ilium - rectus femoris femur - vastus muscles

Question 31

quadriceps femoris - insertion

Answer 31

tibial tuberosity

Question 32

quadriceps femoris - movement

Answer 32

hip - flexion (only rectus femoris) knee - extension

Question 33

hamstrings - 3 sections

Answer 33

1. bicep femoris 2. semimembranosus 3. semitendinosus

Question 33

hamstrings - origin

Answer 33

ischium - long head of bicep femoris - semimembranosus - semitendinosus femur - short head of bicep femoris

Question 34

hamstrings - insertion

Answer 34

tibia - semimembranosus - semitendinosus fibula - bicep femoris

Question 35

hamstrings - movement

Answer 35

hip - extension knee - flexion and rotation (when knee is flexed)

Question 36

tibialis anterior - origin

Answer 36

tibia

Question 37

tibialis anterior - insertion

Answer 37

tarsals

Question 38

tibialis anterior - movement

Answer 38

ankle - dorsiflexion

Question 39

triceps surae - 2 sections

Answer 39

- gastrocnemius (2 heads) - soleus

Question 40

triceps surae - origin

Answer 40

gastrocnemius - condyles of femur soleus - tibia and fibula

Question 41

triceps surae - insertion

Answer 41

calcaneus via calcaneal (Achilles tendon)

Question 42

triceps surae - movement

Answer 42

knee - flexion (gastrocnemius only) ankle - plantarflexion