Skeletal Muscle

Question 1

Functions of skeletal muscle

Answer 1

1. Produce movement
2. Maintain posture and balance
3. Support soft tissue
4. Guard entrances and exits
5. Maintain body temperature

Question 2

Structure of skeletal muscle

Answer 2

1. Contain muscle cells are called “muscle fibre” and supported by connective tissue, blood vessels and nerves.
2. Different from typical cells as they are long (up to 60cm) and multinucleated (nuclei at periphery)
3. Consists of repeated units of myofilament such as thick filaments of myosin and thin filaments of actin. Both filaments interact to produce muscle contraction.

Question 3

What determines the location and shape of muscle?

Answer 3

1. Depends on the muscle function.

E.g thick muscle across joints to produce movement such as biceps
Flat sheet muscle protect support soft tissue such as abdominal organs
Circular muscle are guard openings such as mouth

Question 4

How many muscle makes up the axial muscle?

Answer 4

Made up of 60% skeletal muscle

Question 5

What are the functions for head, neck and face?

Answer 5

Swallowing, facial expression and chewing

Question 6

Functions of muscle for Facial Expressions

Answer 6

A. Thin sheet of muscle beneath the skin and underlying tissue
B. Attached to fascia hence, move only skin
C. Surrounds the lips, eyes, mouth and ears

Question 7

List the muscle of facial expression

Answer 7

1. Frontalis: raise the eyebrow and wrinkles on forehead
2. Orbicularis oculi: surrounds and close the eyes
3. Orbicularis oris: compresses the lips, surrounds the mouth
4. Risorius: draw the angle of mouth laterally
5. Buccinator: compresses the lip and cheeks against the teeth
6. Zygomaticus: draw the lips upward and outward like smiling

Question 8

Muscle of Mastoid Process

Answer 8

1. Temporalis: elevate mandible or closes mouth
   2, Masseter: elevate mandible or closes mouth
2. Pterygloids: move mandible from side to side

Question 9

What are the two muscles of neck

Answer 9

1. Platysma

2. Sternocleidomastoid

Question 10

Describe Platysma

Answer 10

1. Thin sheet of superficial fascia of neck
2. Originated from deep fascia of neck
3. Covers the mandible and skin of cheek
4. Action includes; tense or tightness of neck and depresses mandible

Question 11

Describe sternocleidomastoid

Answer 11

1. Originated from the clavicle and sternum
2. Prominent muscle of both side of neck
3. Covers the temporal of mastoid processes
4. Action includes; flex the neck on both sides and turning face from opposite side

Question 12

List the components of structure that is covered by the muscle of trunk

Answer 12

1. Vertebrae column
2. Thorax
3. Abdominal wall

Question 13

Describe vertebrae column

Answer 13

1. Made up of several layers of muscle arranged in longitudinally
2. Responsible for flexion and extension of head, neck and trunk
3. Muscle involved is “erector spinae muscle”

Question 14

Describe “Aponeurosis”

Answer 14

Thin strong sheet of fibrous tissue

Question 15

2 Muscles under Thoracic Region

Answer 15

1. Intercostal Muscle

2. Diaphragm

Question 16

Describe intercostal muscle

Answer 16

1. Made up of 3 layers of muscle between ribs
   A. External: Elevate Ribs (inhale)
   B. Internal: Depress Ribs (exhale)
   C. Transverse Thoracis: Depress Ribs

Important for respiration

Question 17

Describe Diaphragm

Answer 17

1. Large dome shape that separates the thoracic from abdominal cavity.
2. Consist of 3 openings such as aorta, inferior vena cava and oesophagus
3. Actions include :
   A. Aid in respiration
   B. Assist in abdominal muscle of labour, defecation and micturition

4.supplied by nerves known as phrenic nerve

Question 18

What is the purpose of abdominal wall?

Answer 18

Protect the abdominal organs

Question 19

List the two muscles under abdominal wall

Answer 19

1. Lateral

2. Medial Muscle

Question 20

List the muscle under the lateral muscle

Answer 20

1. External Oblique Muscle:
   A. Broad Thin Muscle
   B. Runs downward medially
   C. Forms the lower border of muscle known as “Inguinal Ligament”
2. Internal Oblique Muscle
   A. Runs upward medially
   B. Beneath the external oblique muscle but superficial to transverse abdominis muscle
3. Transverse Abdominis Muscle
   A. Runs horizontally
   B. Lies deep into internal oblique muscle

Question 21

Describe the medial muscle

Answer 21

1. Consist of rectal muscle
2. Thick muscle on either side of midline
3. Fibre runs vertically
4. Covered by rectal sheath

Question 22

Lists the two segments of medial muscle

Answer 22

1. Linea alba : form medial edge

2. Linea semilunaris: forms lateral edge

Question 23

Action of medial muscle

Answer 23

1. Protect and support abdominal organ
2. Flex and rotate trunk
3. Help in vomiting, micturition, defecation and parturition

Question 24

What is abdominal hernia

Answer 24

Protrusion part of abdomen contents beyond the abdominal wall due to ageing and abdominal surgery