The Muscular System

Question 1

Muscle activity is a response to — from the nervous system

Answer 1

Input

Question 2

The action of a muscle is always to —; Extension is —

Answer 2

1. Contract

2. Passive

Question 3

Muscle contration depends on the interation between what two types of filaments?

Answer 3

Thin & Thick filaments

Question 4

What are thin filaments mostly composed of?

Answer 4

Actin

Question 5

What are thick filaments mostly composed of?

Answer 5

Myosin

Question 6

The vertebrate skeletal muscle helps to move what?

Answer 6

Moves limbs & other body parts

Question 7

The vertabrate skeletal muscle is characterized by what?

Answer 7

A hierarchy of smaller & smaller units

Question 8

A skeletal muscle consists of a bundle of ——, each a ——

Answer 8

1. Long Fibers

2. Single Cell

Question 9

What direction do the fibers of skeletal muscle’s run?

Answer 9

Parallel to the length of muscle

Question 10

What does each muscle fiber consists of?

Answer 10

A bundle of smaller myofibrils

Question 11

How are myofibrils arranged?

Answer 11

Longitudinally(parallel with the muscle fiber) that extend the entire length of the muscle fiber

Question 12

What are the 2 kinds of myofilaments that myofibrils are compsoed of?

Answer 12

Thick & Thin Filaments

Question 13

Staggered arrays of myosin molecules

Answer 13

Thick Filaments

Question 14

Consist of 2 strands of actin & 2 strands of a regulatory protein

Answer 14

Thin Filaments

Question 15

What is the functional unit of a muscle called?

Answer 15

Sarcomere

Question 16

Location where actin filaments are anchored

Answer 16

Z Lines

Question 17

Located where thick filaments are anchored

Answer 17

M Lines

Question 18

A skeletal muscle is also called what? Because the regualar arrangement of myofilaments creates a pattern of light & dark bands.

Answer 18

Striated Muscle

Question 19

Thin & thick filaments ratchet past each other —, this is powered by ——.

Answer 19

1. Logitudinally

2. Myosin Molecules

Question 20

The “head” of a myosin molecule binds to an ——

Answer 20

Actin filament

Question 21

When a myosin molecule binds to an actin filament this forms a ——, & pulls the — filament toward the center of the —

Answer 21

1. Cross-Bridge
2. Thin
3. Sarcomere

Question 22

Muscle contraction requires repeated cycles of this — & —

Answer 22

1. Binding

2. Release

Question 23

When a muscle fiber is at rest — & the —— bind to actin strands on thin filaments

Answer 23

1. Tropomyosin

2. Troponin Complex

Question 24

When tropomyosin and troponin complex bind to actin strands on thin filaments, what does this prevent?

Answer 24

It prevents actin & myosin from interacting

Question 25

For a muscle fiber to contract, the myosin-binding sites on the actin thin filaments must be —

Answer 25

Uncovered

Question 26

When a myosin binding site is uncovered, this occurs when?

Answer 26

Ca2+ ions are high & bind to the troponin complex

Question 27

When do muscle contractions stop?

Answer 27

Concentration of Ca2+ is low (Myosin-binding sites are covered)

Question 28

A twitch results from a single —— in a ——

Answer 28

1. Action Potential

2. Motor Neuron

Question 29

1. Varying the number of fibers that contract
2. Varying the rate at which fibers are stimulates
   What are the 2 mechanisms?

Answer 29

2 basic mechanism by which the nervous system produes graded contractions

Question 30

The extent and strength of its contraction can be voluntarily altered

Answer 30

How the contraction of a whole muscle is graded

Question 31

Each motor neuron may synapse with — muscle fibers, although each fiber is controlled by — motor neuron

Answer 31

1. Multiple

2. One

Question 32

What consists of a single motor neuron and all the muscle fibers it controls?

Answer 32

Motor Unit

Question 33

The more motor units that are recruited, the — the contraction

Answer 33

Stronger

Question 34

More rapidly delivered action potentials produce a graded contraction by —, this process is called —

Answer 34

1. Summation

2. Recruitment

Question 35

State of smooth, sustained contraction when the rate is so high the muscle fiber cannot relax between stimuli

Answer 35

Tetanus

Question 36

Muscles are classified by what 2 sources of ATP powering the muscle activity

Answer 36

1. Oxidative Respiration (oxidative)

2. Glycolyis (glycolytic)

Question 37

What are the speed of muscle contraction?

Answer 37

Slow-twitch & Fast-twitch

Question 38

What do oxidative fibers rely on to generate ATP?

Answer 38

Aerobic Respiration

Question 39

Oxidative Fibers have many —, a rich — supply, & a large amount of —.

Answer 39

1. Mitochondria
2. Blood
3. Myoglobin

Question 40

Binds oxygen more tightly than hemoglobin does

Answer 40

Myoglobin

Question 41

What do glycolytic fibers use as their primary source of ATP?

Answer 41

Glycolysis (Anaerobic Respiration)

Question 42

Glycolytic fiber have — than oxidative fibers, & — more easily

Answer 42

1. Less

2. Tire

Question 43

In poultry and fish, — meat is composed of glycolytic fibers, while — meat is composed of oxidative fibers

Answer 43

1. Light

2. Dark

Question 44

Contract more slowly, but sustain longer contractions & all are oxidative

Answer 44

Slow-twitch

Question 45

Contract more rapidly, but sustain shorter contractions & can be either glycolytic or oxidative

Answer 45

Fast- Twitch

Question 46

Most skeletal muscles contain what slow & fast-twitch muscles in — ratios

Answer 46

Varying

Question 47

Some vertebrates have muscles that twitch at rates —— than human muscles

Answer 47

Much Faster