Chapter 10- Muscle

Question 1

Sarcoplasma:

Answer 1

The cytoplasm of muscle cells.

Question 2

Sarcoplasmic reticulum:

Answer 2

The sarcoplasm and the endoplasmic reticulum

Question 3

Muscle fibers:

Answer 3

The elongated, cylindrical skeletal muscle cells

Question 4

Endomysium:

Answer 4

The layer within a fascicle, where each muscle fiber is surrounded by a fine sheath of loose connective tissue made mostly of reticular fibers.

Question 5

Perimysium:

Answer 5

A layer of fibrous connective tissue surrounding each fascicle.

Question 6

Epimysium:

Answer 6

An outer layer of dense irregular connective tissue surrounding while skeletal muscle.

Question 7

What is a tendon:

Answer 7

The connective tissue structure that joins skeletal muscle to bones

Question 8

Sarcolemma:

Answer 8

The plasma membrane of muscle cells

Question 9

What specific type of tissue makes a tendon?

Answer 9

Fibrous connective tissue and collagen fibers

Question 10

Origin:

Answer 10

Attachment of muscle on less movable bone

Question 11

Insertion:

Answer 11

Attachment of muscle on more moveable bone.

Question 12

What is a fascicle?

Answer 12

Groups that resemble a bundle of sticks with skeletal muscle.

Question 13

What is a myofibril?

Answer 13

Unbranched cylinders that are present in large numbers, making up more than 80% of the sarcoplasm.

Question 14

What are myofilaments?

Answer 14

Filaments of myofibrils, constructed from proteins, primarily myosin or actin.

Question 15

What is a sarcomere?

Answer 15

A structural unit of a myofibril in striated muscle, made of dark bands and the nearer half of each adjacent pale band.

Question 16

Actin filaments:

Answer 16

Attached to Z disc and extending towards center; consists primarily of the protein actin, and other proteins.

Question 17

Myosin filaments:

Answer 17

Center of sarcomere and overlapping inner ends of thin filaments; made largely of myosin molecules and ATPase enzyme that split ATP to release energy for required muscle contraction.

Question 18

Titin:

Answer 18

A spring-like molecule in sarcomere stay resists overstretching.

Question 19

Z discs:

Answer 19

The boundaries at 2 ends of each sarcomere.

Question 20

A bands:

Answer 20

Region of sarcomere where dark bands are created by the full length of the thick filaments, along with the inner ends of the thin filaments, which overlap the thick filaments.

Question 21

I bands:

Answer 21

2 regions on either side of the A band; contain only thin filaments.

Question 22

H zone:

Answer 22

The central part of an A band, where no thin filaments reach.

Question 23

M line:

Answer 23

In the center of the H zone contains tiny rods that hold the thick filaments together.

Question 24

T tubules:

Answer 24

Deep invaginations of sarcolemma that run between each pair of terminal cisterns.

Question 25

Terminal cisterns:

Answer 25

Form larger, perpendicular cross-channels over the junction between each A band in a myofibril and its adjacent I bands (A-I junctions).

Question 26

Structure of neuromuscular junction:

Answer 26

Point where nerve ending and fiber meet. The nerve part of the junction is a cluster of enlargements at the end of the axonal process.

Question 27

Function of neuromuscular junction:

Answer 27

Stores chemical messenger molecules, neurotransmitters.

Question 28

Sliding filament mechanism (theory):

Answer 28

Contraction happens when myosin heads of the thick filaments attach to the thin filaments at both ends of sarcomere and pull the thin filaments toward the center by swiveling inward.

Question 29

Calcium role in sliding filament theory:

Answer 29

Calcium
Is stored in the sarcoplasmic reticulum. Sliding filament mechanism is initiated by release of calcium ions and binds to the thin filaments. Powered by ATP.

Question 30

What happens to the myofilament and to the bands during contraction?

Answer 30

Z discs move closer together.
The I bands shorten.
H zones disappear completely.
A bands stay the same length, because length of thick filaments doesn’t change.

Question 31

Slow oxidative fibers (type I):

Answer 31

Aerobic metabolic reactions slow becuz contract slow.
Fibers are thin and do not generate much power.
Found in postural muscle of lower back.

Question 32

Fast oxidative fibers (type IIa):

Answer 32

Anaerobic metabolism.
Contract slowly.
Fatigue resistant but less so than SO fibers.
More powerful than SO fibers but less powerful than FG fibers. Intermediate thickness.
Found in muscles of lower limbs.

Question 33

Fast glycolytic fibers (type IIx):

Answer 33

Anaerobic pathways. (Less capillaries, pale muscle)
Contain more myofilaments, generate a lot of power (thick).
Contract rapidly, but tire quickly.
Found in upper limbs.

Question 34

Skeletal muscle location:

Answer 34

Attached to bones or (some facial muscles)to skin.

Question 35

Skeletal muscle function:

Answer 35

Movement and maintain posture.

Question 36

Skeletal muscle characteristics:

Answer 36

Single,very long, cylindrical, multinucleated cells with obvious striations.

Question 37

Cardiac muscle location:

Answer 37

Walls of the heart.

Question 38

Cardiac muscle function:

Answer 38

Blood circulation

Question 39

Cardiac muscle characteristics:

Answer 39

Branching chains of cells, uni- or binucleate; striations.

Question 40

Smooth muscle location:

Answer 40

Walls of hollow organs.

Ex: stomach, bladder, uterus, blood vessels, and respiratory tubes.

Question 41

Smooth muscle function:

Answer 41

Regulate blood pressure and blood flow.

Question 42

Smooth muscle characteristics:

Answer 42

Single, fusiform, uninucleated; no striations.