Unit 4: Ch 10 (Muscular System)

Question 1

Action

Answer 1

• The result following a muscle contraction

Question 2

Antagonist

Answer 2

• Performs opposite action as prime mover
• On the opposite side of the prime mover

Question 3

Belly (body)

Answer 3

• Largest portion of muscle that contains proteins required for contraction

Question 4

Cardiac muscle

Answer 4

• Assists in pumping blood; pressure and muscular contractions are important factors
• Intercalated discs that operate as gap junctions
  
  • Zigzag appearance
• Striated
• Involuntary contraction
• Found in the heart

Question 5

Fascia

Answer 5

• Protective covering that surrounds the muscle

Question 6

Fascicles

Answer 6

• A bundle of skeletal muscle fibers
• Determines the strength of a muscle and the direction in which it pulls

Question 7

Fixator

Answer 7

• Stabilizes an axial joint so there’s no dislocation and the intended action is performed

Question 8

Answer 8

Question 9

Innervation

Answer 9

• Nerve fibers that stimulate a skeletal muscle to contract
• 2 groups
  
  • Spinal nerves
  • Cranial nerves

Question 10

Insertion

Answer 10

• Where one end of a muscle is attached to the distal, freely moving bone of its joint

Question 11

Muscle attachments

Answer 11

• Direct (fleshy) attachment
  
  • Cannot see any connective tissue
• Indirect attachment
  
  • Can see connective tissue
  • 3 types
    
    • Tendons: Physically attach muscle to the bone (ie calcaneus)
    • Aponeurosis: Attaches sheet-like muscles needing a wide area of attachment (ie abdomen)
    • Retinaculum: Thicker, found around wrist & ankle regions. Keeps an organ or tissue in place

Question 12

Muscle functional groups

Answer 12

• Extrinsic muscles
  
  • Muscle that originates in another part than that of its insertion
  • Example: muscles originating outside the eye, but affect eye movement
• Intrinsic muscles
  
  • A muscle whose origin and insertion are both in the same part or organ
  • Example: the eye

Question 13

Muscle functions

• General description
• Specific functions

Answer 13

• All muscle types convert chemical energy (ATP) into mechanical energy (movement)
• Functions
  
  • Glycemic control: regulates blood glucose levels
  • Heat production (thermogenesis): heat generation & regulation of body temperature
  • Movement: gross movement (ie joints)
  • Peristalsis: smooth muscle that moves food through the GI system
  • Stability: posture

Question 14

Muscle germ layer

Answer 14

• Mesoderm

Question 15

Muscle layers

Answer 15

• Endomysium
  
  • surrounds the muscle fibers
  • deepest muscle layer
  • areolar connective tissue
• Epimysium
  
  • surrounds the entire muscle/organ
  • provides strength in all 3 planes
  • dense irreg connective tissue
• Perimysium
  
  • surrounds the fascicles
  • dense irreg connective tissue

Question 16

Answer 16

Question 17

Muscle structure identifiers

Answer 17

• Striations (zebra stripes)
• Peripheral nuclei

Question 18

Muscle tissue types

Answer 18

• Cardiac muscle
  
  • Involuntary contraction
  • Striated muscle
  • Intercalated disc
  • Gap junction
  • Assist in pumping blood
  • Example: Heart
• Skeletal muscle
  
  • Voluntary contraction
  • Striated muscle
  • Attached to the bones
  • Multi nuclei on the periphery of the cell
  • Uses skeleton as an anchor for movement
• Smooth muscle
  
  • Involuntary contraction
  • Nonstriated muscle
  • Most organs & digestive system
  • Fusiform shape

Question 19

myo -

Answer 19

Muscle

Question 20

Myology

Answer 20

Study of the muscular system

Question 21

Nomenclature: Attachment site

Answer 21

• Name of a bone in its name
• Example: femorous

Question 22

Nomenclature: Fiber direction

Answer 22

• Refers to a plane in its name
• Example: Internal abdominal oblique

Question 23

Nomenclature: Function

Answer 23

• What results after a muscular contraction
• Example: Adductor longus

Question 24

Nomenclature: Number of origins

Answer 24

• # of locations where you will be able to have a bone originate
• The origin is usually the stationary part of the bone and muscle attachment or anchor
• Example: biceps brachii

Question 25

Nomenclature: Shape

Answer 25

• Partially identified by the shape
• Example: Trapezius

Question 26

Nomenclature: Size

Answer 26

• “Major, magnus, minor”
• Example: Pectoralis minor

Question 27

Origin

Answer 27

• Immobile portion acting as an anchor

Question 28

Prime mover (agonist)

Answer 28

• Muscle that generates the most force

Question 29

sarco -

Answer 29

Meaty/fleshy

Question 30

Shape: Circular muscles

Answer 30

• Form rings around certain body openings
• When they contract, they constrict the opening and tend to prevent the passage of material through it
• Example: external urethral and anal sphincters

Question 31

Shape: Fusiform

Answer 31

• Thick in middle and tapered at each end
• Muscle strength is proportional to the diameter of a muscle at its thickest point
• Example: Biceps brachii

Question 32

Shape: Parallel muscles

Answer 32

• Uniform width and parallel fascicles
• Produce less force than fusiform
• Example: Zygomaticus major or the face

Question 33

Shape: Pennate muscles

Answer 33

• Feather shaped
• Fascicles insert obliquely on a tendon that runs the length of the muscle
• 3 types
  
  • Unipennate
    
    • All fascicles approach the tendon from one side
    • Example: palmar interosseous
  • Bipennate
    
    • Fascicles approach the tendon from both sides
    • Example: rectus femoris
  • Multipennate
    
    • Shaped like a bunch of feathers with their quills converging on a single point
    • Example: deltoid of the shoulder

Question 34

Shape: Triangular (convergent) muscles

Answer 34

• Fan shaped
• Broad at one end and narrower at the other
• Examples: Pectoralis major

Question 35

Skeletal muscle

Answer 35

• Connection with the muscular system; an anchor to create a movement that can be seen at the gross level
• Striated
• Peripheral nuclei
• Attached to bone
• Voluntary contraction

Question 36

Smooth muscle

Answer 36

• Fusiform shape
• Non-striated
• Involuntary contraction
• Found in most organs (ie digestive system)

Question 37

Synergist

Answer 37

• Helper muscle to the prime mover
• On the same side of bone as the prime mover

Question 38

What identifies the type of contraction that can be performed?

Answer 38

Muscle shape

Question 39

Muscle nomenclature

Answer 39

• Naming muscles
  
  • Fiber direction (ie transverse, oblique)
  • Attachment site (ie name of bone)
  • Size (ie major, minor, magnus)
  • Shape (ie trapezius, orbicularis)
  • Function (ie adductor, abductor, flexor)
  • Number of origins (ie biceps, quadriceps, triceps)