Unit 2: Muscular System

Question 1

-movement
-stability
-control of body opening/passages
-heat production

Answer 1

functions of skeletal muscle

Question 2

-responsiveness to stimulus
-exhibits electrical and mechanical responses

Answer 2

excitability

Question 3

electrical excitation is conducted throughout the entire plasma membrane

Answer 3

conductivity

Question 4

unique characteristic of shortening when stimulated

Answer 4

contractility

Question 5

can stretch without breaking

Answer 5

extensibility

Question 6

has ability to return to original length after stretching

Answer 6

elasticity

Question 7

shortening and lengthening of a muscle through a complete range of motion

Answer 7

isotonic

Question 8

muscle shortening with contraction

Answer 8

concentric

Question 9

muscle lengthening with contraction

Answer 9

eccentric

Question 10

contracts the muscle statically without a change in muscle length

Answer 10

isometric

Question 11

resistance is given at a fixed velocity with accommodating resistance

Answer 11

isokinetic

Question 12

surrounds entire muscle

Answer 12

epimysium

Question 13

surrounds bundles of the muscle fibers

Answer 13

perimysium

Question 14

surrounds individual muscle fibers

Answer 14

endomysium

Question 15

Answer 15

muscle fascicle

Question 16

-multi-nucleated muscle cell
-contains dozens to hundreds of myofibrils
-each myofibril is divided further
-arranged in a highly structured pattern

Answer 16

muscle fibers

Question 17

contracting strands within sarcoplasm made up of a long series of sarcomeres

Answer 17

myofibrils

Question 18

Answer 18

muscle filaments

Question 19

-connective tissue attaching muscle to bone
-improve leverage
-economize space
-make it possible for the muscle to act from a distance

Answer 19

tendons

Question 20

tendon fibers that penetrate into the bone

Answer 20

sharpey’s fibers

Question 21

muscle cell membrane

Answer 21

sarcolemma

Question 22

storage site for calcium

Answer 22

sarcoplasmic reticulum

Question 23

enlarged lateral sacs of sarcoplasmic reticulum next to transverse tubule

Answer 23

terminal cisternae

Question 24

-channels that extend deep within the muscle cell
-bring action potential deep and throughout muscle cell

Answer 24

transverse tubules

Question 25

-thin filaments -contractile proteins

Answer 25

actin

Question 26

-thick filaments -contractile proteins -(looking at #13)

Answer 26

myosin

Question 27

-attached on the actin filament -both involved in regulating muscle contraction -regulate myosin and actin binding -regulatory proteins

Answer 27

troponin and tropomyosin

Question 28

-individual segments of the myofibrils -extends from z-line to z-line

Answer 28

sarcomere

Question 29

(looking at D)

Answer 29

A band

Question 30

(looking at C)

Answer 30

I band

Question 31

Answer 31

H zone

Question 32

Answer 32

M line

Question 33

Answer 33

Z line (disc)

Question 34

-all muscle fibers within a motor unit are the same type -if the threshold value for neuron firing is reached, all muscle fibers within a motor unit contract maximally -smaller motor units offer fine movement control -larger motor units offer more gross control

Answer 34

motor unit characteristics

Question 35

the special synapse between a branch of a motor neuron and the sarcolemma of a skeletal muscle fiber

Answer 35

neuromuscular junction

Question 36

1. AP proceeds to synapse 2. Ca2+ enters nerve 3. Vesicles move to membrane 4. Vesicles fuse with membrane 5. ACh released into cleft 6. ACh binds receptor on post-synaptic membrane 7. Na+ enters muscle 8. AP continues down sarcolemma 9. ACh removed from cleft

Answer 36

Activities at the synapse

Question 37

1. AP enters muscle through t-tubules 2. Ca2+ is released when "triad" region depolarizes 3. Ca2+ binds troponin 4. Troponin removes tropomyosin from "active site" 5. Myosin strongly binds the active site 6. Muscular contraction begins

Answer 37

Excitation-Contraction sequence

Question 38

1. ACh released from vesicles in terminal axon 2. Action potential depolarizes t-tubules 3. Depolarization causes Ca2+ to be released from SR 4. Ca2+ binds to troponin- a) tropomyosin moves exposing the binding sites b) Myosin heads bind with actin 5. Myosin heads bind to actin and myosin ATPase releases energy and produces movement 6. ATP binds to myosin head "breaking" crossbridge bond 7. Crossbridge activation continues with presence of Ca2+ (maintains open sites on actin) 8. Lack of AP causes Ca2+ to move back to SR (terminal cisternae) 9. Actin & myosin remain in disassociated site in presence of ATP

Answer 38

steps to muscle contraction

Question 39

-in a stretched muscle, there are less cross-bridge formations due to less overlap of the contractile filaments -refers to optimizing cross-bridging -length of muscle affects cross-bridging

Answer 39

length-tension relationship

Question 40

-does not require oxygen -phosphagen system -glycolysis -i.e. kicking a football

Answer 40

anaerobic

Question 41

-requires oxygen -occurs in mitochondria -oxidative phosphorylation -i.e. 10,000m run

Answer 41

aerobic

Question 42

fast twitch oxidative glycolytic

Answer 42

Type IIa

Question 43

fast twitch glycolytic

Answer 43

Type IIx or IIb

Question 44

Slow twitch oxidative

Answer 44

Type I

Question 45

-increase in muscle size -2 types: sarcoplasmic and myofibrillar

Answer 45

hypertrophy

Question 46

-result in major adaptations in strength during initial weeks of resistance training -due to increases in neural activation of muscle and better coordination of muscles involved in movement

Answer 46

neural adaptations

Question 47

decrease in fiber size after training is stopped

Answer 47

atrophy

Question 48

if stimulus triggers action potential, all fibers in motor unit will contract

Answer 48

all or none principle

Question 49

-The orderly recruitment of motor units is due to variations in motor neuron size -As force increases, motor units with larger neurons are recruited

Answer 49

size principle

Question 50

is the principle muscle producing a motion or maintaining a posture

Answer 50

agonist

Question 51

muscle must cross a joint to move that joint

Answer 51

mover rule

Question 52

produces the opposite effect as the agonist

Answer 52

antagonist

Question 53

muscles that assist the agonist and contract at the same time

Answer 53

synergist

Question 54

prevent unwanted movement in a joint

Answer 54

stabilizers/fixators

Question 55

-detect dynamic and static changes in muscle length -stretch reflex

Answer 55

muscle spindle

Question 56

-monitor tension developed in muscle -prevents damage during excessive force generation

Answer 56

golgi tendon organs

Question 57

attachment to stationary part of the skeleton

Answer 57

origin

Question 58

attached to moveable portion of the skeleton

Answer 58

insertion

Question 59

muscle fibers aligned parallel to line of pull

Answer 59

fusiform

Question 60

muscle fibers arranged at an angle to the line of pull

Answer 60

pennate

Question 61

two pinnated muscle fibers aligned in opposite directions and angled to line of pull

Answer 61

bipennate

Question 62

fibers fan out from a large origin/insertion to a smaller insertion/origin

Answer 62

multipennate