Muscular system

Question 1

There are over ______ skeletal muscles.

Answer 1

700

Question 2

what are the 3 types of muscle tissues?

Answer 2

skeletal muscle (attach to bone)
cardiac muscle (makes up heart)
smooth muscle (functions of digestive system, beyond conscious control)

Question 3

What are some characteristics of muscle?

Answer 3

muscle cells are long, narrow, elongated

muscle cell = muscle fiber

muscle is the only tissue capable of movement [through contraction- microfilament movement]

Question 4

what are the 4 properties of muscle tissue?

Answer 4

1) excitability- responds to stimuli
2) contractibility- generates tension & shortens cell length
3) extensibility- returns to relaxed state
4) elasticity- resists stretching

Question 5

The property of muscle cells that directly enables movement is:

Answer 5

contractibility

Question 6

what are the functions of skeletal muscles tissue?

Answer 6

body movement

maintenece of posture

protection & support

guard openings

heat production

Question 7

fascicle:

Answer 7

bundle of muscle fibers

-surrounded by perimysium CT [dense irregular CT]

Question 8

Skeletal muscle connective tissue are composed of:

Answer 8

collagen, elastic fiber

Question 9

Skeletal muscle connective tissue functions:

Answer 9

-protection
-blood vessel and nerve distribution
-attachment to skeleton

Question 10

each individual muscle cell/fiber is surrounded by:

Answer 10

endomysium

Question 11

myofibrils

Answer 11

make up muscle fibers

-made of myofilaments

Question 12

what is the connective tissue over the entire muscle?

Answer 12

epimysium

Question 13

what are the 4 patterns of skeletal muscle fiber organization?

Answer 13

1) parallel

2)convergent

3) pennate

4) circular/ sphincter

Question 14

parallel muscles

Answer 14

muscle fascicles organized parallel to long axis of the muscle.

ex) biceps brachii; rectus abdominis

-allows the greatest distance of movement
-but relatively weak in proportion to their size

Question 15

convergent muscles

Answer 15

triangular, has a broad base and narrow toward attachment site

-movement in different directions

ex) pectoralis major of chest

Question 15

pennate muscles

Answer 15

feathered-like appearance, has central tendon to which vasicles are attached

-strongest muscle pattern
-don’t contract over much distance

ex) rectus femoris, extensor digitorum

Question 16

circular muscles

Answer 16

concentric, around an opening

AKA sphincter muscle

-contracts, diameter of circle gets smaller

ex) orbicularis oris (eye)

Question 17

direct VS indirect muscle attachment

Answer 17

direct
-periosteum and epimysium directly attached

indirect
-rope-like tendon attaches muscle to bone, skin, or other muscle
-thin flattened aponeurosis/tendon

Question 18

which muscle pattern is widespread over a broad area and joined at a common attachment site?

Answer 18

convergent

Question 19

The bundle of dense regular connective tissue that attaches a skeletal muscle to bone is called a(n):

Answer 19

tendon

Question 20

The muscle that assists the agonist is called the:

Answer 20

synergist

Question 21

A muscle attachment that is a thin, flat sheet is:

Answer 21

aponeurosis

Question 22

The connective tissue that surrounds a fascicle is:

Answer 22

perimysium

Question 23

A muscle that surrounds an opening is:

Answer 23

circular muscle (sphincter)

Question 24

An individual muscle fiber (cell) is covered by a layer of connective tissue insulation called the:

Answer 24

endomysium

Question 25

sarcolemma

Answer 25

muscle fibers' plasma membrane

Question 26

sarcoplasm

Answer 26

muscle fibers' cytoplasm

Question 27

sarcoplasmic reticulum

Answer 27

muscle fibers' Smooth ER

Question 28

what are the 2 main structures that are unique to muscle fibers?

Answer 28

1) transverse tubules (T-tubules)- carry impulses from sarcolemma to help stimulate contraction 2) sarcoplasmic reticulum [internal membrane complex] -stores calcium used to initiate contraction -includes terminal cisternae adjecent to T-Tubules -triad= 2 terminal cisternae + 1 T-Tubule

Question 29

Myofibrils

Answer 29

cylindrical structures within muscle fibers that run the length of the cell -make up 80% of fiber volume -can shorten, resulting in contraction of muscle fiber -contain MYOFILAMENTS

Question 30

Myofilaments & 2 types

Answer 30

strands of protein that allow for contraction 2 types 1) thick : made of hundreds of bundled myosin molecules 2) thin : made of 2 strands of filamentous actin (F-Actin) twisted around each other; also has 2 regulatory proteins- tropomyosin and troponin

Question 31

Myosin

Answer 31

Each myosin molecule has 2 strands, 2 intertwined tails, each with a head

Question 32

sarcomere

Answer 32

structural and functional units within a myofibril -contains overlapping thick and thin filaments -one sarcomere spans from one Z disc to the next

Question 33

The plasma membrane of a skeletal muscle fiber is called the:

Answer 33

sarcolemma

Question 34

In a skeletal muscle fiber, a triad is composed of:

Answer 34

one T-tubule and two terminal cisternae

Question 35

The functional contractile unit of a skeletal muscle fiber is the:

Answer 35

sarcomere

Question 36

The protein found in thick filaments is:

Answer 36

myosin

Question 37

The sarcomere region with thin filaments only is the :

Answer 37

I band

Question 38

the visible striations in skeletal muscle fibers are attributed to:

Answer 38

arrangement of thick and thin filaments in the myofibril

Question 39

Doing the splits is what kind of movement?

Answer 39

abduction of the femur

Question 40

what kind of movement is a butterfly stretch?

Answer 40

flexion at the knee lateral rotation of femur

Question 41

A back bend is what kind of movement?

Answer 41

extension of the back

Question 42

sliding filament theory

Answer 42

during contraction, thin filaments slide past thick filaments -Z discs move closer together, so sarcomeres shorten -Width of A bands remain constant, but H zones dissapear -I bands narrow

Question 43

the M line contains:

Answer 43

thick filaments and accessory proteins

Question 44

the H zone contains:

Answer 44

thick filaments

Question 45

The A band contains:

Answer 45

thick and thin filaments

Question 46

The Z disc contains:

Answer 46

thin filaments, connectin, accessory proteins

Question 47

which event occurs during skeletal muscle contraction?

Answer 47

the area of actin and myosin overlap increases

Question 48

globular myosin heads bind to :

Answer 48

actin filaments

Question 49

neuromuscular junction

Answer 49

place where the motor neuron communicates with muscle fiber

Question 50

skeletal muscle fibers are excited by:

Answer 50

axons of somatic motor neurons

Question 51

motor unit

Answer 51

a single motor neuron and all of the muscle fiber it controls

Question 52

in muscle contraction, a neurotransmitter:

Answer 52

diffuses across a synapse from a neuron to a muscle cell

Question 53

what is the role of the sarcoplasmic reticulum in muscle contraction?

Answer 53

it stores CA2+ [calcium] ions for release during contraction

Question 54

when animals die, the lack of ATP causes muscles to stiffen in rigor mortis because:

Answer 54

actin and myosin cannot separate without ATP

Question 55

skeletal muscle

Answer 55

voluntary, striated -moves and stabilizes skeleton -made of myofibers>sarcomeres -once mature, the skeletal muscle cells cannot divide or replace

Question 56

cardiac muscle

Answer 56

involuntary, striated -only found in heart -extensive interconnections at intercalated discs>desmosomes>gap junctions -pacemaker cells set contraction rate of heart -.5-1% of cardiac tissue is replaced yearly

Question 57

smooth (visceral) muscle

Answer 57

involuntary, non-striated -remained of body's muscle tissue after skeletal and cardiac -all muscle tissue that are not consciously controlled and not apart of the heart -digestive system, urinary structures, blood vessels, glands, reproductive tract.. -have actin and myosin fibers, but not arranged into sarcomeres, making it non-striated -short fusiform cells -1 central nucleus -slow, efficient, fatigue resistant contractions

Question 58

What is the connective tissue covering indicated by B in the above image?

Answer 58

perimysium

Question 59

In the above image, the pre-synaptic cell would be found at:

Answer 59

A

Question 60

What is indicated by #17 in the above image?

Answer 60

myofibril

Question 61

The cellular structure responsible for storing calcium in the resting skeletal muscle cell is the:

Answer 61

sarcoplasmic reticulum

Question 62

The repetitive unit of contractile proteins (composed of overlapping thin and thick protein filaments) that extends from Z line to Z line is called the:

Answer 62

sarcomere

Question 63

Do neurons get in direct physical contact with the muscle cells they control?

Answer 63

No

Question 64

What is the name of the structure covered by connective tissue covering A in the above image?

Answer 64

muscle

Question 65

What is the name of #21, the three closely associated structures in the above picture?

Answer 65

triad

Question 66

In skeletal muscle, another name for the synapse is:

Answer 66

“neuromuscular junction”.

Question 67

Do skeletal muscle cells appear striated under the microscope?

Answer 67

yes

Question 68

are muscle cells also called myofibrils?

Answer 68

NO

Question 69

What type of action would be produced by a muscle anterior to the knee that is attached to bones proximal and distal to the knee?

Answer 69

extension of the leg at the knee

Question 70

Is parallel or pennate muscle fiber stronger?

Answer 70

pennate

Question 71

What is the connective tissue covering indicated by A in the above image?

Answer 71

epimysium

Question 72

The connective tissue that surrounds each muscle cell is the:

Answer 72

endomysium.

Question 73

What is indicated by #20 in the above image?

Answer 73

terminal cisternae of the sarcoplasmic reticulum

Question 74

What is indicated by #18 in the above image?

Answer 74

mitochondria

Question 75

The region above indicated by A is:

Answer 75

I band

Question 76

The region indicated by B in the above image is:

Answer 76

H zone

Question 77

Which structure in the above image represents the anchor for the thick filaments?

Answer 77

C

Question 78

Muscle fascicles are composed of bundles of :

Answer 78

muscle cells.

Question 79

The repetitive unit of contractile proteins (composed of overlapping thin and thick protein filaments) that extends from Z line to Z line is called the:

Answer 79

sarcomere

Question 80

The end of a skeletal muscle that is moved when the muscle contracts is called the:

Answer 80

insertion

Question 81

The connective tissue “sheath” that wraps around each muscle fascicle within a muscle is the:

Answer 81

perimysium

Question 82

During the contraction of a sarcomere, calcium ions bind with the protein _____.

Answer 82

troponin

Question 83

Which molecule directly supplies energy to myosin to allow the filaments to continue to contract?

Answer 83

ATP

Question 84

Contractions called _____ occur whenever the forces applied to a muscle are increased, but the muscle does not appear to be moving.

Answer 84

isometric

Question 85

The degeneration of muscle fibers caused by a lack of proper stimulation and usage is called _____.

Answer 85

atrophy

Question 86

________________muscle fibers provide powerful contractions but fatigue quickly.

Answer 86

Fast-twitch

Question 87

Which type of muscle is found in the wall of blood vessels?

Answer 87

multi-unit smooth muscle

Question 88

transverse tubules (T-tubules)

Answer 88

carry impulses from sarcolemma to help stimulate contraction

Question 89

what is the cellular structure responsible for rapid transmission of the action potential over a skeletal muscle cell?

Answer 89

transverse tubule

Question 90

thin filaments are composed mainly of:

Answer 90

actin

Question 91

the sarcoplasmic reticulum of a resting muscle cell contains large quantities of:

Answer 91

calcium ions

Question 92

at the synapse, a neuron releases neurotransmitters into the:

Answer 92

synaptic cleft

Question 93

what is the longest muscle in the body?

Answer 93

Sartorius

Question 94

the microscopic functional unit of the muscle cells that extends from Z line to Z line is called:

Answer 94

Sarcomere