Muscle Unit

Front 1

Differences between type 1 and type 2 muscle fiber

Back 1

type 1: smaller, motor neuron smaller, fatigue slower, more myoglobin, slow twitch

type 2: bigger, larger neuron, fatigue faster, less myoglobin, fast twitch

Front 2

Sarcolemma

Back 2

plasma membrane, capable of being stimulated by the nervous system

Front 3

T-tubules

Back 3

transverse tubules that carry the electrical signal from the sarcolemma into the cell

Front 4

Sarcoplasmic reticulum

Back 4

wrapped around the myofibrils, capable of storing releasing, and up taking calcium

Front 5

Sarcomere

Back 5

small contractile unit of the muscle

Front 6

Muscle contraction occurs by sliding _______ and ______ _________ across one another

Back 6

thick and thin filaments

Front 7

Thick =

Back 7

myosin, has globular head on one end

Front 8

Thin =

Back 8

actin, also including troponin and tropomyosin

Front 9

Sliding Filament Theory of muscle contraction

Back 9

Myosin head bind on the actin filament and "slide" down to shorten the muscle -- and contract

Front 10

How does contraction occur?

Back 10

Essentially, an electrical signal stimulates calcium to move the blockers, and ATP will be split to power the actin/myosin binding over and over to shorten the muscle fiber

Front 11

Step 1 :

Back 11

Motor neuron sends a signal, an action potential, to the muscle fiber to contract

Front 12

Step 2:

Back 12

The signal, (action potential) is then passed along the sarcolemma and into the interior of the cell down the T-tubules and to the sarcoplasmic reticulum

Front 13

all or none principle:

Back 13

The action potential passes across the ENTIRE innervated muscle fiber

Front 14

Step 3:

Back 14

The action potential causes Ca to be released from the SR throughout thick and thin filaments

Front 15

Step 4:

Back 15

Calcium binds to the troponin and tropomyosin t move them off the binding sites - the blocker is removed

Front 16

Step 5:

Back 16

The active sit on actin open, the myosin heads will now be able to bind at them

The sarcomere -myofibril - muscle fiber are shortened as ATP is used to power myosin heads binding over and over with actin

Front 17

Ca's role is ________

Back 17

opening binding sites

Front 18

ATP is broken down into _______ and ______

Back 18

ADP and Pi

Front 19

The energy from the ATP is used here to make the __________ _________ "pull" the actin and shorten the muscle

Back 19

myosin heads

Front 20

Different groups of skeletal muscles

Back 20

1. velocity (speed of contraction)

2. force (of contraction)

3. economy (ATP cost per unit of time during contraction)

Front 21

Traditional method of classifying fibers

Back 21

Slow (type 1) fast (type 2)

Red v white

Front 22

Immunohistochemical is the __________ _________ of type fibers

Back 22

gold standard

Front 23

Isoforms

Back 23

different forms of the same protein

Front 24

________ heavy chain is the molecule that is most often used

Back 24

Myosin

Front 25

Each myosin can contain:

Back 25

1-2 diff "heavy chain" isoforms (red part)

2-4 diff "light chain" isoforms (MLC)

Front 26

In mammals _____ diff MHC isoforms exist

Back 26

10

Front 27

In human, adult, skeletal muscles, theres are 3 MHC isoforms:

Back 27

type I

type II a

Type IIb

Front 28

Each fiber contains ___________ of myosin, each fiber will contain a mixture of ______ MHC isoforms

Back 28

>1000's of myosin's

3

Front 29

Slow twitch Red:

Back 29

5 type 1 slow oxidative

Front 30

Fast twitch white

Back 30

Type IIa fast oxidative glycolytic FOG fibers

Type IIb/ x Fast glycolytic

Front 31

Muscle fibers are classified by what

Back 31

PRIMARY MHC

Front 32

Motor units are group by:

Back 32

primary fiber type they contain ( I, IIA, or IIB)

Front 33

Type I, IIA, IIB motor units, Type I, IIA, IIB fibers:

Back 33

SO

FOG

FG

Front 34

Comparison of motor neurons: (Chart)

Back 34

Front 35

Henneman's Size Principle

Back 35

Small motor units have a lower recruitment threshold

Front 36

Low force production recruits =

Back 36

smaller units

Front 37

High force production recruits =

Back 37

small and large units

Front 38

Advantages of size principle:

Back 38

1. Orderly recruitment of motor units conserves

2. Allows for smooth increases

Front 39

Comparison structure

Back 39

Front 40

Comparison function

Back 40

Front 41

Comparison- metabolic

Back 41

Front 42

Fiber comparison relative to each other

Back 42

Front 43

Muscle fiber typed assessed in 2 ways:

Back 43

muscle needle biopsy

nuclear magnetic resonance

Front 44

By counting fibers we can estimate a percent balance between _______ and _______

Back 44

fast twitch and slow twitch

Front 45

Examples where slow twitch fibers would be

Back 45

Neck muscles, postural control, diaphragm

Front 46

Examples where fast twitch fibers would be

Back 46

Bicep, tricep, pecs, eye muscles

Front 47

____________ gradually transitions a fiber type to the next closest type

Back 47

Training

Front 48

Next neighbor rule:

Back 48

Can go in either direction but only to the next one over, cannot skip one

Front 49

Endurance fibers transition to the:

Back 49

left

Front 50

During resistance training (anaerobic) the fibers ______________

Back 50

funnel towards each other

Front 51

Contraction types:

Back 51

Isotonic

Isometric

Front 52

Isotonic =

Back 52

constant muscle load

concentric and eccentric

Front 53

Isometric =

Back 53

constant muscle length

Front 54

isokinetic =

Back 54

constant joint angle velocity

Front 55

Where would isokinetic "training" occur most often?

Back 55

Lab

Rehab

Front 56

Strength =

Back 56

maximal force

Front 57

Muscular endurance =

Back 57

sustained force

Front 58

Power =

Back 58

strength and speed

Front 59

What are the differences between adolescent males and females?

Back 59

Muscle mass

Front 60

Hypertrophy of the muscle (resistance training)

Back 60

Increased synthesis of contractile proteins, increase int the number of actin and myosin

Front 61

Hyperplasia =

Back 61

increased number of muscle fibers

Front 62

Fiber type is ________ and _________

Back 62

genetic and plays a role in performance