Muscular System

Question 1

The forces that help the body perform physical activity are supplied by the ________.

Answer 1

Muscular system.

Question 2

What are muscle cells also known as?

Answer 2

Fibers

Question 3

Muscle cells, also known as fibers, are _________ and connected in __________.

Answer 3

Muscle cells, also known as fibers, are multinucleated and connected in cylindrical bundles or individual cells.

Question 4

What is a single muscle built from?

Answer 4

Many bundles of muscle fibers called fascicule.

Question 5

Connective tissues run from one end of the muscle to the other to what?

Answer 5

To bind cells together and giving rise to muscle fiber bundles.

Question 6

Muscle tissues are categorized into three types according to what? And what are they?

Answer 6

Function and structure.

Cardiac, smooth and skeletal.

Question 7

Where is cardiac muscle found?

Answer 7

In the walls of the heart.

Question 8

What does the smooth muscle compose?

Answer 8

Composes the epithelial of other hollow organs.

Question 9

What do the cardiac muscle and smooth muscle have in common?

Answer 9

They are both under involuntary control.

Question 10

Skeletal muscle is attached to what? Is it under voluntary or involuntary control?

Answer 10

Skeletal muscle is attached to the skeleton and is under voluntary control.

Question 11

Skeletal muscle is composed of many what?

Answer 11

Many thread-like striations.

Question 12

What is the basic unit of the myofibril?

Answer 12

The sarcomere.

Question 13

How does the sarcomere expand?

Answer 13

Expands from z Z line to the next closest Z line.

Question 14

What are sarcomeres composed of?

Answer 14

Alternating large myosin and thin actin strands made of protein.

Question 15

Where does myosin develop?

Answer 15

In the middle of every M line.

Question 16

What is the M line?

Answer 16

It is a line that runs the length of myofibrils.

Question 17

What do the actin strands develop? How is it characterized?

Answer 17

A Z shaped pattern down the points that are anchored, which is characterized by having a darker color than other areas.

Question 18

What happens when stimulation occurs and an action potential is received?

Answer 18

The skeletal muscles carry out a contraction by decreasing every sarcomere.

Question 19

Actin and myosin fibers overlap in a _______.

Answer 19

Contractile motion toward each other.

Question 20

How would you describe myosin filaments? Where do they project?

Answer 20

Club-shaped heads that project toward the actin filaments.

Question 21

In relation to myosin filaments, what are the larger structures called? Where are they found? And what do they do?

Answer 21

Myosin heads. Found along the myosin filament and give attachment points on binding sites for the actin filaments.

Question 22

How and where do myosin heads move? What do they do when they get there? What is this process called? And what happens as a result?

Answer 22

Myosin heads move in a synchronized manner toward the center of the sarcomere. They then detach and reattach to the closest active site of the actin filament. This is known as a “ratchet type drive system.” As a result, this process uses up large quantities of adenosine triphosphate (ATP).

Question 23

Where does the energy for contraction come from?

Answer 23

It comes directly from ATP.

Question 24

What is the energy source of a cell?

Answer 24

ATP.

Question 25

What is the job of ATP?

Answer 25

To link the cross bridges among myosin heads and actin filaments.

Question 26

What powers the twisting of the myosin head?

Answer 26

Energy.

Question 27

What happens when ATP is used up?

Answer 27

ATP converts to adenosine diphosphate (ADP).

Question 28

A person's muscles accumulate a small amount of ATP by __________.

Answer 28

Constantly reusing the ADP and converting it back into ATP quickly.

Question 29

Inside muscle tissues there is a what? What does this assist?

Answer 29

There is a storage supply of a high-speed recharge chemical called creatine phosphate. This assists in producing the fast renewal of ADP into ATP.

Question 30

When is a muscle stimulated to contract?

Answer 30

When calcium is released.

Question 31

A muscle is stimulated to contract when calcium is released from the ___________.

Answer 31

Sarcosplasmic reticulum into the sarcomere.

Question 32

What is needed for every cycle of the sarcomere?

Answer 32

Calcium ions.

Question 33

What does calcium reveal?

Answer 33

The actin binding sites.

Question 34

What happens when a muscle does not need to contract?

Answer 34

Calcium ions are drawn out from the sarcomere and are stored back in the sarcoplasmic reticulum.

Question 35

As a whole unit, skeletal muscles produce movement by ______.

Answer 35

Pulling on the skeleton in a nervous system-controlled manner.

Question 36

What happens when a muscle shortens?

Answer 36

It moves a bone by pulling on the tendons which attack the muscle to the bones.

Question 37

What do the integration of bones, skeletal muscles and joints create?

Answer 37

The apparent movements like running and walking.

Question 38

Skeletal muscles and joints can generate movements that are more subtle like _____.

Answer 38

Respiration, eye movements and facial expressions.

Question 39

The number of skeletal muscles used during a workout depends entirely on

Answer 39

which exercises are chosen and the | methods used during their implementation.

Question 40

The skeletal muscles are grouped together, though this does not mean

Answer 40

that they function together.

Question 41

Skeletal muscles can either function _____.

Answer 41

They can either function separately | or in groups along with other muscles.

Question 42

What is formed by the action of skeletal muscles?

Answer 42

Power and muscle force.

Question 43

Muscle contraction movement can fulfill several other vital functions in the human body like what? (3)

Answer 43

Heat production, posture and joint stability.

Question 44

Sitting and standing with posture can be accomplished by

Answer 44

Contraction of muscles.

Question 45

As soon as the nervous system triggers movement in the body, the entire muscle does not respond, why?

Answer 45

Because a muscle has several motor units (a motor neuron and the muscle fibers it innervates) and the movement may require just a small part of the muscle.

Question 46

All of the fibers contract when

Answer 46

A motor unit is stimulated.

Question 47

Clusters of motor units work in unison to

Answer 47

manage the contractions of a muscle.