The Muscle System

Question 2

Musculoskeletal system

Answer 2

Comprised of muscles and skeltons

Question 3

Muscles and skeletons are ____ that produce movment

Answer 3

effectors

Question 4

3 types of vertebret muscle

Answer 4

skeletal, cardiac, smooth

Question 5

Skeletal muscle involves

Answer 5

voluntary movement, breathing

Question 6

Cardiac involves

Answer 6

beating of the heart

Question 7

Smooth muscle

Answer 7

involuntary, movement of internal organs

Question 8

What does it mean when skeletal muscles are “striated”

Answer 8

they have “strips” of muscle cells

Question 9

skeletal muscle cells are called

Answer 9

muscle fibers

Question 10

Muscle fibers are extremely ____, _____ cells

Answer 10

large - multinucleated

Question 11

Skeletal muscles form by _____ of _____

Answer 11

fusion of embryonic myoblasts

Question 12

One muscle consists of many _____ bundled together by connective tissue

Answer 12

muscle fibers

Question 13

Each muscle fiber has several ______

Answer 13

myofibrils

Question 14

Myofibrils consist of

Answer 14

bundles of actin and myosin filaments

Question 15

The contractile proteins

Answer 15

Actin and myosin

Question 16

Actin are ____ filaments

Answer 16

thin

Question 17

Myosin are ____ filaments

Answer 17

thick

Question 18

Sarcomere

Answer 18

overlapping actin and myosin filaments

Question 19

Each myofibril consists of repeating units called

Answer 19

Sarcomeres

Question 20

Titin and what does it do?

Answer 20

the largest protein in the body that holds bundles of myosin filaments in place

Question 21

Describe the “sliding filament mechanism”

Answer 21

myosin heads bind to specific sites on actin molecules to form cross bridges, then change conformation to cause the actin filments to slide 5-10 nm

Question 22

During the sliding filament mechanism mysoin heads _____ to specific sites on ____ to form ______

Answer 22

bind; actin; crossbridges

Question 23

Muscle contration is initiated by ______ from a ____ neuron at the ______

Answer 23

action potentials, motor neruon, neuromuscular junction

Question 24

A motor unit

Answer 24

all the muscle fibers that are activated by one motor neuron

Question 25

Muscle cells are inhibited or excited?

Answer 25

excited

Question 26

the plasma membrane of the muscle cells can ____ action potentials

Answer 26

conduct

Question 27

\_\_\_\_ is released by the motor neuron at the ______ and opens _____ in the \_\_\_\_\_\_\_

Answer 27

ACH; neuromuscular junction; ion channels; motor end plate

Question 28

The chemical synapse between a motor neuron and a muscle cell is

Answer 28

the neuromuscular junction

Question 29

Action potentials move through fibers via

Answer 29

T-tubules (transverse tubules)

Question 30

T-tubules descend into the

Answer 30

sarcoplasm (muscle fiber cytoplasm)

Question 31

The sarcoplasm is

Answer 31

the muscle fiber cytoplasm

Question 32

T-tubules run close to the

Answer 32

sarcoplasmic reticulum

Question 33

The sarcoplasmic reticulum (SR) is

Answer 33

a closed compartment that surrounds every myofibril, the ER of muscle cells

Question 34

the SR has ____ pumps

Answer 34

Ca2+

Question 35

At rest here is a ____ concentration of Ca in the _____ of the SR

Answer 35

high concentration; lumen

Question 36

An action potential will ____ Ca channels and Ca flows ______ of the SR and triggers the interaction of

Answer 36

open; out; action and myosin

Question 37

Actin filaments also include

Answer 37

tropomyosin and troponin

Question 38

3 subunits of troponin bind to \_\_\_,\_\_,\_\_\_

Answer 38

actin, tropomyosin, and Ca2+

Question 39

At rest, _____ blocks binding sites on actin

Answer 39

tropomyosin

Question 40

Troponin changes conformation when

Answer 40

Ca2+ is released and binds to it

Question 41

Tropomyosin is bound to _____ and the twisting of it exposes ___ on actin

Answer 41

troponin; binding sites

Question 42

When ___ pumps remove Ca2+ from the sarcoplasm, ____ stops

Answer 42

Ca2+; contraction

Question 43

The cardiac muscle is also striated

Answer 43

True

Question 44

The cardiac muscle cells are ____ than skeletal muscle cells and have how many nuclei?

Answer 44

smaller; just one nucleus

Question 45

Cardiac muscle cells can withstand high pressures due to

Answer 45

branching and interdigitating

Question 46

What initiates and coordinates heart contractions?

Answer 46

pacemaker and conducting cells

Question 47

The heartbeat is generated by the heart muscle itself which means that it is

Answer 47

myogenic

Question 48

Heart transplantations are possible because

Answer 48

the autonomic NS modifies the rate of pacemaker cells, but isnt nescessary

Question 49

Cardiac and smooth muscle cells are arranged in

Answer 49

sheets

Question 50

cells in cardiac sheets are in electrical contact vi

Answer 50

gap junctions

Question 51

the cell sheets allow an action potential to ___ to all others in the sheet, so the heart can _____ contractions

Answer 51

spread; sync

Question 52

what connects the cytoplasm of two neighboring cells and allow electrical communication?

Answer 52

gap junctions

Question 53

Gap junctions in cell sheets allow ___ and ____ muscle cells to contract simultaneously

Answer 53

cardiac and smooth

Question 54

The simplest muscle cells

Answer 54

smooth muscle cells

Question 55

smooth muscle cell contains just

Answer 55

one cell/nucleus

Question 56

They are "smooth" muscle cells because

Answer 56

actin/myosin are not as regularly arranged

Question 57

Smooth muscle cells are under ____ control

Answer 57

Autonomic NS control

Question 58

What is a twitch

Answer 58

minimum unit of contraction by skeletal muscle

Question 59

Twitch is measured in terms of

Answer 59

tension

Question 60

A _____ generates a twtich

Answer 60

a single action potential

Question 61

If action potentials are close together the twitches add up.

Answer 61

True

Question 62

How do twitches build up?

Answer 62

calcium pumps can't clear out all the Ca from the sarcoplasm before the next one comes and it piles up

Question 63

Tetanus is

Answer 63

when APs are so frequent that this is always calcium in the sarcoplasm

Question 64

How long a muscle fiber can sustain tetanic contraciton depends on ____ supply

Answer 64

ATP

Question 65

What is needed to break actin/mysoin bonds and "re-cock" the heads?

Answer 65

ATP

Question 66

To maintain contraction...

Answer 66

actin-myosin bonds have to keep cycling

Question 67

3 systems for muscles to obtain ATP

Answer 67

Immediate, glycolytic, oxidative

Question 68

Immediate system

Answer 68

uses pre-formed ATP and creatine-phosphate

Question 69

Glycolytic system

Answer 69

metabolizes carbs to pyruvate and lactic acid; anaerobic

Question 70

Oxidative system

Answer 70

carbs and fatty acids to H2O and CO2 (aerobic)

Question 71

Creatine phosphate (CP) ___ energy in a ____ bond that can transfer to ADP

Answer 71

stores energy in a phosphate bond

Question 72

ATP+CP is the ____ system

Answer 72

immediate

Question 73

The ATP from the ____ immediate system is exhusted within seconds; ___ yield of ATP

Answer 73

immediate; low yield of ATP

Question 74

In the glycolytic system, enzymes are in the \_\_\_\_\_\_\_

Answer 74

sarcoplasm/cytoplasm

Question 75

ATP generated during glycotic system is not directly available to myosin

Answer 75

False, its FAST!

Question 76

Is glycotic system aerobic or anaerobic?

Answer 76

Anerobic

Question 77

Glycotic system has a ___ ATP yild

Answer 77

Low as well

Question 78

Immidate and glycolytic systems provide energy for \_\_\_\_\_

Answer 78

less than one minute

Question 79

Oxidative phosphorylation occurs in the

Answer 79

Mitochondria

Question 80

Oxidative method makes _____ of ATP and is \_\_\_\_

Answer 80

a lot of; aerobic (CO2) is created

Question 81

ATP must ____ from the mitochondria to the ____ in the cytoplasm, therefore it is ____ than the other two systems

Answer 81

diffuse; mysoin; slower

Question 82

Two main types of skeletal muscle fibers

Answer 82

slow and fast twitch

Question 83

The slow twitch muscle fibers are the _____ or ___ muscle

Answer 83

oxiative or red

Question 84

ST fibers contain ____ which is the oxygen binding protein

Answer 84

myoglovin

Question 85

ST fibers contain many _____ and \_\_\_\_\_

Answer 85

Mitochondria and blood-vessels

Question 86

In ST fibers, max tension develops ____ and is _____ to fagitue

Answer 86

slowly; highly resistant

Question 87

ST fibers have reserves of what?

Answer 87

Glycoghen and fat

Question 88

ST fibers and produce ATP as long as ____ is avaialble

Answer 88

oxygen

Question 89

ST fibers are good to use with ____ excercise

Answer 89

aerobic exercise

Question 90

Fast-twitch muscle fibers are ____ or ___ muscles

Answer 90

glycolytic/white

Question 91

Complete opposite of ST fibers - _____ mitochonrdria, blood vessels, myoglobin

Answer 91

LITTLE

Question 92

FT fibers develop max tension ____ and fatigue \_\_\_\_\_\_-

Answer 92

faster and faster

Question 93

FT fibers can replenish ATP for prolonged contraction

Answer 93

FALSE

Question 94

What determines muscle strength and endurance?

Answer 94

The proportion of ST and FT fibers

Question 95

Genetic heritage plays a role in determining

Answer 95

Proportion of ST and FT fibers

Question 96

Training a muscle can alter muscle properties

Answer 96

True (to an extent)

Question 97

Anerobic exercise increases muscle \_\_\_\_\_.

Answer 97

Strength

Question 98

What happens when a muscle gets stronger?

Answer 98

new actin/myosin filaments form, muscle gets JACKED

Question 99

Aerobic exercise increases muscle \_\_\_\_\_

Answer 99

Endurance

Question 100

What happens when muscle gains endurance?

Answer 100

oxidative capacity is enhanced due to the increase in mitochondria, blood vessels, myoglobin, and enzymes