Muscular Organization - Lecture 19

Question 1

Which is the predominant muscle type in the body?

Answer 1

Somatic Striated Voluntary Skeletal muscle

Question 2

Which type of skeletal muscle does the Musculoskeletal system address?

Answer 2

The striated voluntary skeletal muscle

Question 3

Which muscle type is found in the blood vessels and alimentary canal?

Answer 3

Smooth involuntary visceral muscle

Question 4

Which muscle type is least common and found only in the heart?

Answer 4

Cardiovascular System

Question 5

List the 3 types of muscles in the body

Answer 5

Striated voluntary skeletal muscle. Smooth involuntary visceral muscle and cardiovascular muscle

Question 6

Which system is the skeletal muscle controlled by?

Answer 6

By the Somatic Nervous System which is out conscious nervous system

Question 7

The skeletal muscles cells are marked by a distinctly - describe this distinction

Answer 7

They are makes by striation (stripes) and the fibers themselves are multinucleated and can be several centimeters long

Question 8

Are skeletal muscles voluntary or involuntary?

Answer 8

Voluntary. We control their movement and are consciously intiating their contraction

Question 9

Are the skeletal muscles attached to skeleton? If so, what happens when they contract?

Answer 9

They are directly or indirectly attached to the Skelton and move the skeleton when they contract

Question 10

List the 4 functional types

Answer 10

Fixator - hold a joint or bone steady during contraction

Agonist the prime mover that does the heavy lifting in a muscle contraction

Synergist aids the agonist in completing the action in a smooth and graceful manner

Antagonist- resist the movement of the agonist. This is necessary because it controls the speed and strength of contraction

Question 11

Which functional group resists the movement of the agonist?

Answer 11

Antagonist

Question 12

Which functional group is the prime mover?

Answer 12

Agonist

Question 13

Which functional group locks in the joint or bone during contraction?

Answer 13

Fixator

Question 14

Which functional group aids the agonist in completing their action?

Answer 14

Synergist

Question 15

Mysial tissue and structure

What tissue is the skeletal muscle formed by?

Answer 15

Formed by fibrous connective tissue, both the mysial tissue and the tendon package and attach to muscle to bone

Question 16

Mysial tissue and structure

What does the epimysium do?

Answer 16

It envelopes the entire muscle bundle

Question 17

What does the skeletal perimysium form?

Answer 17

It forms fascicles within the muscle consisting of a few hundred muscle fibers and ir can sometimes be accompanied by adipose tissue (a ready source of energy.)

Question 18

What is the role of the endomysium?

Answer 18

It packages each muscle fiber in a layer of connective tissue

Question 19

What comes together at the heads of muscle to form a tendon that insets into the bone?

Answer 19

Mysial layers

Question 20

Why is the muscle fiber called a fiber and not a cell?fiber

Answer 20

Because if it’s length and unique structure is called a

Question 21

What is the cell membrane called in skeletal muscle fiber? What’s the rest of its anatomy ?

Answer 21

Sarcolemma and there is an inner fluid the sadeoplasm. The sarcolemma has interior extensions called T-rubles. .

The sarcolemma contains sarcoplasmic reticulum and numerous mitochondria

Question 22

Where is the multiple nuclei of the single muscle fiber ?

Answer 22

It’s shoved asides and inactived . Mature muscles can’t replace themselves

Question 23

What is the interior packed with ?

Answer 23

Myofibrils which are made up of myofilaments

Question 24

Sarcomere

What are each myofibril that can be separated into called?

Answer 24

Sarcomeres which is what actually contracts the muscle

Question 25

What contracts the muscle ?

Answer 25

Sarcomere

Question 26

What are the milofilaments made of up and how many? And what is the elastic component called?

Answer 26

They’re are made of up two myofilaments. The thick filament, made up of myosin… the thin filament made up of protein called actin.

There is also an elastic component called titin which attaches the tips of the thick filaments to the Z sucks.

Question 27

Sarcomere

What is the actin myofilaments fixed to?

Answer 27

The Z disc, which forms the boundary of the sarcomere. The myosin is fixed to the M line in the middle of the sarcomere.

Question 28

What are the striarions due to ?

Answer 28

The over lap of the myofilaments in the A band, which appear darker than the non overlap regions

Question 29

Striations

Describe the striations

Answer 29

I band - clear area with the Z disc in the center. The thin actin filaments are here.

A band - denser area found in the middle of the sarcomere. The think myosin filament are here

Z disc in the middle of the I band and forming the boundary of the sarcomere. It is the attachment point fo the the thin filaments.

M line - in the middle of the A bandZ it is the attachment for the thick filaments

H bands less dense area in the middle of the A bands and in either side of the M line. Touch filaments are not overlapped by thin filaments here.

Question 30

According to the Sliding Filament Theory how do muscles contract?

Answer 30

By having the thick and thin filaments slide over each other in each sarcomere

The process is initiated by when the muscle fiber is stimulated to contract either electorally or by nerve. Once contraction begins each satcom carried out a full contraction with the filaments going to maximum overlap. These is done by the means of cross bridges formed between thin and thick filaments