L04 - Muscle and movement

Question 1

What are the different classifications of striated muscle ?

Answer 1

1. Flat muscles
2. Pennate muscles
3. Fusiform muscles
4. Convergent muscles
5. Quadrate muscles
6. Circular muscles
7. Multiheaded/ Multibellied muscles

Question 2

On what basis are striated muscles classified?

Answer 2

Depends on the direction of their fibres and their shape

Question 3

Appearance of flat muscles?

Answer 3

Parallel fibres often with an aponeurosis

Question 4

Example of a flat muscle

Answer 4

External oblique (broad flat muscle) 
- The sartorius (narrow flat muscle with parallel fibres)

Question 5

Appearance of pennate muscles?

Answer 5

Feather-like in the arrangement of their fasicles

- May be unipennate, bipennate or multipennate

Question 6

Example of unipennate muscle?

Answer 6

Extensor digitorum longus (wrist and finger extensor)

Question 7

Example of bipennate muscle?

Answer 7

Rectus femoris

Question 8

Example of multipennate muscle?

Answer 8

Deltoid

Question 9

Appearance of fusiform muscles?

Answer 9

Spindle-shaped with a roung, thick belly (or bellies) and tapered ends

Question 10

Example of fusiform muscle?

Answer 10

Biceps brachii

Question 11

Appearance of convergent muscles?

Answer 11

Arises from a broad area and converge to form a single tendon

Question 12

Example of a convergent muscle?

Answer 12

Pectoralis major

Question 13

Appearance of quadrate muscles?

Answer 13

Has four equal sides

Question 14

Example of quadrate muscle?

Answer 14

Rectus abdominis between its tendinous intersections

Question 15

Appearance of circular (sphincteral) muscles?

Answer 15

Surrounds a body opening or orifice, constricting it when contracted

Question 16

Example of circular muscle?

Answer 16

Orbicularis oculi (closes eyelids)

Question 17

Appearance of mult-headed muscle

Answer 17

Has more than one head of attachment or more than one contractile belly

Question 18

Example of multiheaded muscles?

Answer 18

• Biceps muscles have two heads of attachment (biceps brachii)
• Triceps muscles have three heads of attachment (triceps brachii)

Question 19

What are the different functions of muscles?

Answer 19

1. Prime mover (agonist)
2. Fixator
3. Synergist
4. Antagonist

Question 20

Function of prime mover muscle?

Answer 20

• Main muscle responsible for producing a specific movement of the body
• Contracts concentrically to produce the desired movement