Chapter 10: Muscular System

Question 1

do muscles push or pull?

Answer 1

only pull

Question 2

how many muscles in human body

Answer 2

approx 600

Question 3

functions of muscle

Answer 3

• move body parts
• move contents of organs (smooth and cardiac)
• posture and prevent movement
• communication
• body openings
• heat production

Question 4

prime movers

Answer 4

muscles that provide major force for producing a specific movement

Question 5

antagonists

Answer 5

muscles that oppose or reverse a movement

Question 6

synergists

Answer 6

muscles that add force to a movement
reduce undesireable/unnecessary movement
*fixers: synergists that immobilize a bone or muscle’s origin

Question 7

muscles can be organized by

Answer 7

• location
• shape
• relative size (maximus vs minimus vs longus)
• direction of fibers
• number of origins
• location of attachments
• action

Question 8

fascicles

Answer 8

-bundles of myocytes surrounded by perimysium membrane

Question 9

parallel fascicles

Answer 9

run parallel to long axis of muscle

Question 10

fusiform fascicles

Answer 10

spindle shaped muscles (biceps brachii)

Question 11

pennate fascicles

Answer 11

short fascicles that attach obliquely to central tendon running length of muscle

Question 12

convergent fascicles

Answer 12

converge from a broad origin to a single tendon insertion

Question 13

circular fascicles

Answer 13

fascicles are arranged in concentric rings

Question 14

direct muscle attachment

Answer 14

• epimysium of muscle is continuous with periosteum of bone

- relatively uncommon (intercostal muscles)

Question 15

indirect muscle attachment

Answer 15

• epimysium collects into a tendon or aponeurosis that attaches to periosteum via perforating fibers
• most common

Question 16

intrinsic muscles

Answer 16

contained within region moved by their contraction

Question 17

extrinsic muscles

Answer 17

muscles move body parts outside of region where they are found

Question 18

lever

Answer 18

rigid bar that moves on a fulcrum (fixed point)

Question 19

effort

Answer 19

force applied to a lever

Question 20

load

Answer 20

resistance moved by effort

Question 21

interactions between effort, length, and load

Answer 21

1. effort x length of effort arm = load x length of load arm

2. (force x distance) = (resistance x distance)

Question 22

power lever

Answer 22

lever operates at mechanical advantage

Question 23

speed lever

Answer 23

lever operates at mechanical disadvantage

Question 24

first class lever system

Answer 24

fulcrum is between load and effort (like raising head off chest)

Question 25

second class lever system

Answer 25

load is between fulcrum and effort (standing on tip toe)

Question 26

third class lever system

Answer 26

effort applied between fulcrum and load

Question 27

epicranius aka | occipitofrontalis

Answer 27

``` bipartite muscle -frontalis -occipitalis along with galea aponeurotica: cranial aponeurosis connecting the muscles move scalp forward and backward cranial nerve VII (facial nerve) insert in skin (instead of bone) ```

Question 28

grinding muscles

Answer 28

lateral pterygoid | medial pterygoid

Question 29

major head flexor

Answer 29

-sternocleidomastoid

Question 30

synergists to head flexion

Answer 30

suprahyoid and infrahyoid

Question 31

lateral head movements

Answer 31

sternocleidomastoid and scalene

Question 32

head extension

Answer 32

splenius muscles and trapezius muscles

Question 33

erector spinae

Answer 33

- prime mover of back extension - three columns on each side of vertebrae: 1. ilicostalis 2. longissimus 3. spinalis

Question 34

deep thoracic muscles

Answer 34

movement for breathing 1. external intercostals: inspiration superficial layer, lifts rib cage and increases thoracic volume 2. internal intercostals: expiration deeper layer 3. diaphragm: most important for inspiration at rest

Question 35

abdominal wall

Answer 35

internal and external obliques transversus abdominis and rectus abdominis run at right and oblique angles, strength

Question 36

pectoralis major

Answer 36

arm flexion

Question 37

latissimus dorsi and deltoid

Answer 37

arm extension

Question 38

middle fibers of deltoid

Answer 38

arm abduction

Question 39

rotator cuff muscles

Answer 39

reinforce capsule of shoulder | secondarily act as synergists and fixators

Question 40

forearm extension

Answer 40

triceps brachii

Question 41

forearm flexion

Answer 41

brachialis biceps brachii act as synergist, stabilize elbow

Question 42

small muscles in palm of hand

Answer 42

control precise movements main abductors and adductors produce opposition, move thumb toward little finger

Question 43

thigh flexors

Answer 43

hamstring muscles - biceps femoris - semitendinosus - semimembranosus

Question 44

extensor of knee

Answer 44

quadriceps femoris

Question 45

evert foot

Answer 45

lateral compartment muscles fibularis longus fibularis brevis

Question 46

flex food and toes

Answer 46

``` posterior compartment muscles =gastrocnemius -soleus -tibialis posterior -flexor digitorum longus -flexor hallucis longus ```