TEST 3 Muscle Fibers

Question 1

Properties and Char of Muscle Tissue(4)

Answer 1

1) Contractility 2) Excitability 3) Extensibility 4) Elasticity

Question 2

Different Types of Muscle

Answer 2

1)Skeleton 2) Cardiac 3) Smooth

Question 3

Functions of Muscle(3)

Answer 3

Movement 2) Posture 3) Temperature regulation

Question 4

What is a muscle cell called

Answer 4

Muscle fiber

Question 5

Covering Layers Outside to in

Answer 5

1) Deep Fascia 2) Epimysium 3) Perimysium 4) Endomysium

Question 6

Aponeurosis

Answer 6

narrow tendon

Question 7

Origin

Answer 7

Less movable

Question 8

Insertion

Answer 8

More Movable

Question 9

Anatomy of A skeletal Muscle fiber

Answer 9

1) Covered by endomysium 2) Sarcolemma (plasma membrane) 3) Sarcoplasm(cytoplasm) 4) Bundles of Myofibrils 5) Covered with Sarcoplasmic Reticulum joining together with 6) Transverse (t) Tubules which are open to sarcolemma

Question 10

Sarcolemma Plasma

Answer 10

membrane of a muscle fiber Surrounds muscle fiber and regulates entry and exit of materials

Question 11

Myofibrils

Answer 11

Organized bundles of myofilaments; cylindrical structures as long as the muscle fiber itself. Contain myofilaments that are responsible for muscle contraction Myosin(thick); Actin(thin) and Titin

Question 12

Sarcoplasm

Answer 12

Cytoplasm of a muscle fiber

Question 13

Sarcoplasmic reticulum

Answer 13

Smooth endoplasmic reticulum in a muscle fiber Function: Stores calcium ions needed for muscle contraction.

Question 14

Thick filament

Answer 14

Fine protein myofilament composed of bundles of myosin

Question 15

Thin filament

Answer 15

Fine protein myofilament composed of actin; troponin; and tropomyosin

Question 16

Transverse tubule (T-tubule) Define and Function

Answer 16

Narrow; tubular extensions of the sarcolemma into the sarcoplasm; contacting the terminal cisternae; wrapped around myofibrils. Function: Quickly transports a muscle impulse from the sarcolemma throughout the entire muscle fiber

Question 17

Actin

Answer 17

Double-stranded contractile protein Binding site for myosin to shorten a sarcomere. Has two associated proteins Troponin and Tropomyosin

Question 18

Tropomyosin

Answer 18

Double-stranded regulatory protein. COVERS the myosin active sites on ACTIN preventing myosin from binding to actin when muscle fiber is at rest

Question 19

Troponin Function

Answer 19

Regulatory protein that holds tropomyosin in place and anchors to actin. When CALCIUM ION BINDS to one of its subunits; troponin changes shape; causing the tropomyosin to move off the actin active site; and this permits myosin binding to actin

Question 20

Myosin

Answer 20

Thick Filament made from myosin molecules has two Heads (crossbidges) and Tails. Head has a site for ATP(looks like 2 twisted golf clubs)

Question 21

Sarcomere

Answer 21

1) Functional unit of skeletal muscle(function contractile unit) It is defined as the distance from one Z disc to the next adjacent Z disk. Each myofibril contains many Sarcomeres. Sarcomeres Give skeletal muscle it STRIPED appearance

Question 22

A band

Answer 22

Composes of an entire Thick filament(Myosin)

Question 23

H zone

Answer 23

The distance between thin filaments that shortens when muscle contracts(does not contain thin filaments)

Question 24

I Band

Answer 24

contains only thin filaments and titin proteins goes across 2 sarcomeres

Question 25

M line

Answer 25

Midline of the (A) band

Question 26

Titin

Answer 26

Provides structural support and elasticity to the sarcomere

Question 27

Neuromuscular Junction(NMJ)

Answer 27

Site where a motor neuron meets a muscle fiber(LAB TEST). Acetylcholine(ach) is release from a electrical signal

Question 28

sarco-

Answer 28

muscle

Question 29

Skeleton Muscle Char

Answer 29

1) Multinuciated 2) Highly ORGANIZED 3) Lots of Many mitochondria

Question 30

action potential

Answer 30

electrical signal

Question 31

Motor Unit(MU)

Answer 31

A motor neuron and all the muscle fibers it innervates(all fibers within a MU are the Same Type

Question 32

Small vs Large Motor Unit

Answer 32

Gross movement (hips) vs (eyes; fingers) small group of muscles

Question 33

Muscle contraction theory

Answer 33

1) Sliding filament theory: myofilaments slide past each other this is accomplished by the cross-bridge cycle.

Question 34

Cross- bridge cycle

Answer 34

Cross-bridges on myosin bind actin and pull actin across myosin with a supply of ATP

Question 35

When a muscle contracts do sarcomere length and myofilaments shorten?

Answer 35

Sarcomeres Shorten; myofiliaments stay the same length

Question 36

What causes Striations(dark vs light)

Answer 36

The overlap of Thin and Thick filaments

Question 37

Acetylcholine(ach) Cause what

Answer 37

Causes an action potential on the sarcolemma and when it reaches the T-tubules it goes down into the muscle fibers CAUSing the Sarcoplasmic Reticulum(SR) to release CALCIUM

Question 38

Excitation-Contraction Coupling

Answer 38

Action potential release Calcium in SR which then can bind to Tropin . This cause the troponin to move tropomyosin out of the way so actin and myosin can interact. If ATP is available cross-bridge cycle occurs

Question 39

When do contraction stop?

Answer 39

when the stimulus from the nervous system is removed and calcium is pumped back into the SR

Question 40

Types of Muscle contraction

Answer 40

Dynamic(concentric and eccentric)(shortening/lengthening) and Static(ISOmetric) (holding object not moving (not isotonic)

Question 41

3 types of Muscle Fibers

Answer 41

Type 1(SLOW; oxidative; slow-twitch) 2) Type 2a (fast oxidative; glycolytic fast twitch fatigue-resistant) 3) Type 2b (fast glycolytic fast twitch fatigable.

Question 42

Type 1 Fiber type Char(6)

Answer 42

1 )ATP mainly made aerobically 2)High # of mitochondria 3)High # of capillaries4) Contract slowly 5)Moderate force production 6)Fatigue resistant

Question 43

Type 2b Fiber type Char(6)

Answer 43

1) ATP mainly made anaerobically 2) Low # of mitochondria 3)Low # of capillaries 4)Contract fast 5) High force production 6)Fatigue easily

Question 44

Atrophy(muscle)

Answer 44

Muscles get smaller

Question 45

Hypertrophy(muscle)

Answer 45

Muscles get bigger

Question 46

Hyperplasia(muscle)

Answer 46

Increase # of fibers (not in humans)

Question 47

Roles of muscles (4) and char

Answer 47

1) agonist(prime mover) 2) Antagonist (opposite movement) 3) Synergist(helps out but not main muscle) 4) Fixator/stabilizer(hold in place)(shoulder)

Question 48

Cardiac Muscle Char

Answer 48

1) striated 2) 1-2 nuclei 3) branched 4) intercalated discs 5) auto rhythmic(own electrical wiring)

Question 49

Smooth Muscle Char

Answer 49

1)fusiform shape 2) 1 nuclei 3) involuntary 4) slow 5) fatigue resistant 6) nonstriated 7) DENSE BODIES 8) form vessels and viscera(internal organs) 9) twisting contraction

Question 50

Anabolic steroids

Answer 50

Family of hormones that are similar to testosterone in the body Increase protein synthesis and give male secondary sex characteristics There is conclusive evidence that they increase muscle strength and mass However; several dangerous side effects make their use unhealthy and illegal!