L2: Muscle & Fascia

Question 1

What are contractile fibers responsible for?

Answer 1

Contractile fibers responsible for movement, controlled by nervous stimuli.

Question 2

What are the sites of skeletal muscles?

Answer 2

• Attached to bone.
• Around joints.
• 40-50% of body mass.

Question 3

What are the sites of smooth muscles?

Answer 3

• Wall of internal viscera (longitudinally & circularly) to produce peristalsis.
• In blood vessels to control the lumen caliber.
• In storage organs to produce expulsion of contents.

Question 4

What are the sites of cardiac muscles?

Answer 4

In myocardium.

Question 5

Compare between skeletal, smooth and cardiac fibers according to contraction and striation

Answer 5

Question 6

What are the nerve supply and control of skeletal muscle fibers?

Answer 6

Somatic mixed nerve (motor & sensory).

Question 7

What is the nerve supply and control of smooth muscle fibers?

Answer 7

• Autonomic nerves
• Also, controlled hormonally
• And by local stretch action.

Question 8

What is the nerve supply and control of cardiac muscle fibers?

Answer 8

• Autonomic nerves

- conducting system: spontaneous rhythmic contraction

Question 9

What is the shape of the muscle cell in skeletal muscle fibers?

Answer 9

Multi nucleated

Question 10

What is the shape of muscle cell in smooth muscle fibers?

Answer 10

Spindle-shaped with single nucleus.

Question 11

What is the shape of muscle cells in cardiac muscle fibers?

Answer 11

Spiral, Branch & unite together (one syncytium).

Question 12

What are the attachments of a skeletal muscle?

Answer 12

2 attachments:

1) Origin: is the more fixed attachment.
2) Insertion: is the more mobile attachment.

Question 13

What are the functions of skeletal muscles?

Answer 13

1) Produce movement.
2) Maintain posture.
3) Stabilize joints.
4) Generate heat.

Question 14

What are skeletal muscles classified into according to fascile arrangement?

Answer 14

1- Fusiform
2- Parallel
3- Convergent
4- Unipennate
5- Bipennate
6- Multipennate
7- Circular

Question 15

What are skeletal muscles classified according to the action of muscles?

Answer 15

1- Prime movers

2- Antagonists

3- Synergists

4- Fixators (stabilizers)

Question 16

What is the function of prime movers? and give an example.

Answer 16

• Responsible for initiation of movement.

Example: brachialis in elbow flexion.

Question 17

What is the function of antagonists? and give an example.

Answer 17

• oppose action of prime movers.

Example: triceps antagonizes elbow flexion produced by
brachialis.

Question 18

What are the functions of synergists? and give an example.

Answer 18

• Act with each other to perform with more efficient contraction.

Example: Biceps helps brachialis muscle.

Question 19

What are the functions of fixators? and give an example.

Answer 19

• Stabilize the joint on which the prime mover acts.

Example: rotator cuff muscles stabilize the humerus which is the origin of brachialis

Question 20

What are skeletal muscles classified into according to the number of joints the act upon?

Answer 20

Uni-articular: Brachialis

Bi-articular: Sartorius

Multi-articular: Flexors and extensors of the digits

Question 21

What is Lou Gehrig’s disease?

Answer 21

Is a fatal neurologic disease that attacks the neurons responsible for controlling voluntary muscles.

Question 22

What are the earliest symptoms of Lou Gehrig’s disease?

Answer 22

The earliest symptoms may include cramping, twitching, and muscle weakness,

Question 23

What happens to muscles with Lou Gehrig’s disease with time?

Answer 23

The muscles gradually atrophy, and patients lose the ability to swallow, speak and finally to breath.

Question 24

What is fascia and what are its types?

Answer 24

-Connective tissue lying between skin & underlying muscles & bones.

-Superficial fascia, Deep fascia

Question 25

What are the characters of superficial fascia?

Answer 25

1) Mixture of loose areolar & fatty tissue that lies between skin & deep fascia. 2) Dense in the scalp, the palm of the hand, sole of foot & back of the neck. 3) Thinnest with no fat: over penis, scrotum, eyelid, auricle of the ear 4) May contain (fat, cutaneous vessels, nerves, lymphatics, and glands)

Question 26

What is the function of superficial fascia?

Answer 26

1) Bad conductor to heat so keeping body temperature constant. 2) Fills up hollows & rounds off irregularities so gives rounded appearance & smooth outline particularly in females. 3) Facilitates skin movement over underlying structures. 4) Acts as a medium for cutaneous vessels, nerves & lymphatics.

Question 27

What are the definition of deep fascia?

Answer 27

-Membranous layer of connective tissue that is denser & lies deep to superficial fascia. -It is present in the neck, upper & lower limbs.

Question 28

What are the types of deep fascia?

Answer 28

- Investing fascia: covers surface of the muscle. - Inter-muscular septa: lie between muscles. - Retinacula: localized transverse thickenings of deep fascia around wrist and ankle joints to hold long tendons in place. - aponeurosis: thicker parts of deep fascia in the palm of hand and sole of foot and scalp - sheaths for neuromuscular bundles: As femoral and carotid sheathes. - tendons: Fibrous bands that connect muscles to bones or cartilage or connecting abdominal viscera. - Ligaments: Fibrous bands like tendons that connect bones to bones or cartilage or are folds of the peritoneum serving to support visceral structures. - Raphe: The line of union of symmetrical muscles through interdigitation of their tendentious ends.