General Anatomy (intro To Myology)

Question 1

What are the properties of muscles?

Answer 1

1. Excitable or Irritable: Ability to receive and to respond to stimuli from the nerves
2. Contractible: Ability to respond to stimuli by contracting
3. Extensible: ability to be stretched without damage by the application of force
4. Elastic: ability to return to its original resting shape and length after being extended or contracted
5. Adaptable: ability to change in response to how it is used (able to undergo hypertrophy with increased work; or atrophy with no use.

Question 2

What are some functions of the muscles?

Answer 2

● Locomotion
● Speaking
● Facial expresion
● Chewing
● Breathing
● Circulation
● Digestion
● Stability to joints
● Posture
● Vision
● Organ protection
● Childbirth

Question 3

What are the three types of muscle?

Answer 3

• cardiac muscle
• skeletal muscle
• smooth muscle

Question 4

What are skeletal muscles?

Answer 4

• Voluntary muscles
• Connected to bones
• Composed of striated muscle fibres
• PNS controls skeletal muscles to perform body movements (walking, sitting)

Question 5

What are smooth muscles?

Answer 5

• Involuntary muscles
• Found in the walls of the hollow internal organs (uterus, blood vessels,
  intestines)
• Non-striated muscle fibres with single nucleus
• Perform gradual and rhythmic contractions under the control of ANS
  (digestion of food)

Question 6

What are cardiac muscles?

Answer 6

• Muscle of the heart
• Found in the walls of the heart
• Striated muscle fibres with single nuclei
• Perform involuntary, strong, and rhythmic contractions of the heart (pumping
  blood to the whole body)

Question 7

What is the function of the muscular system?

Answer 7

All three types of muscles also work together. For example, when you run (performed by skeletal muscles), there is more pumping of blood by the heart (cardiac muscle), and heavier breathing (smooth muscle).

Question 8

What are the shapes of the muscles?

Answer 8

• Deltoid - triangle
• Trapezius - Trapezoid
• Serratus anterior - jagged edge
• Orbicularis Oculi, Orbicularis oris - oval
• Rhomboideus major - a parallelogram with adjacent sides of unequal lenghts

Question 9

What are the muscles according to their location?

Answer 9

Frontalis
Vastus lateralis
Tibialis anterior
Fibularis
Supraspinatus
Infraspinatus
Subscapularis

Question 10

What are the muscles according to the size?

Answer 10

Gluteus maximus
- maximus - largest
- minimus - smallest
- Vastus - huge

Fiburalis longus
- longus - longest
- brevis - short

Pectoralis major
- major - large
- minor - small

Question 11

What are the muscles according to the direction?

Answer 11

• Rectus abdominis - rectus (straight) - parallel to the muscle’s long axis
• Transversus abdominis - At right angles to the muscle’s long axis
• External oblique - diagonal

Question 12

What are the muscles according to their actions?

Answer 12

• Abductor - Adductor
• Flexor - Extensor
• Levator - Depressor
• Sphincter - Dilator
• Rotator - opponens (opposition)

Question 13

What are the arrangement of the muscle fibres?

Answer 13

• Fusiform - Biceps brachii
• Parallel - Rectus abdominis
• Convergent - Pectoralis major
• Unipennate - Palmar interosseous
• Bipennate - Rectus femoris
• Multipennate - deltoid
• Circular - Orbicularis oculi

Question 14

What is a muscle fibre?

Answer 14

A single cylindrical muscle cell, which is surrounded by connective tissue called the endomysium.

Question 15

What is a fasciculus?

Answer 15

A bundle of muscle fibres surrounded by a layer of connective tissue called the perimysium

Question 16

What is an Epimysium?

Answer 16

Each muscle is surrounded by a connective tissue sheath called the epimysium. Portions of the epimysium project inward to divide the muscle into compartments

Question 17

What are skeletal muscles?

Answer 17

Skeletal muscle cells are soft and fragile like other body cells. The connective tissue covering provides
support and protection for the delicate cells, allowing them to withstand the forces of contraction. The coverings also give pathways for the passage of blood vessels and nerves.

Question 18

What are the types of muscle contractions?

Answer 18

● Concentric – muscles are shortened, generating the force.
● Eccentric – muscles become elongated in response to a greater opposing force.
● Isometric – force is generated without
changing the length of the muscle.
● Concentric and eccentric are termed “isotonic” (length of muscle is changed).

Question 19

What are the roles of muscles?

Answer 19

● Muscles work together to bring about movement.
● Agonist: The muscle(s) that provides the major force to complete the movement
(‘prime movers’).
○ The agonist is not always the muscle that is shortening (contracting concentrically). In a bicep curl exercise, the bicep is the agonist on the way up when it contracts concentrically, and on the way down whenitcontractseccentrically. Thisisbecauseitistheprimemoverinbothcases.
● Synergist: The muscles that help provide movement for the prime mover
● Antagonist: The muscle with the opposite action of the prime mover (also to maintain the position)
● Stabilizer: The muscles which act to stabilize one joint so the desired movement can be performed in another joint.

Question 20

Muscle power grading?

Answer 20

● 0 – No contraction
● 1 – Twitch, flicker/ trace contraction
● 2 – Active movement, not against gravity
● 3 – Active movement, against gravity, but not against resistance
● 4 – Active movement, against gravity, against some resistance
● 5 - Active movement, against gravity, against full resistance