Chapter 10- Muscular System

Question 1

Fascia

Answer 1

a band or sheet of connective tissue, primarily collagen, beneath the skin that attaches, stabilizes, encloses, and separates muscles and other internal organs.

Question 2

Muscle Fascicle

Answer 2

a bundle of skeletal muscle fibers surrounded by perimysium, a type of connective tissue

Question 3

Epimysium

Answer 3

• a sheath of fibrous elastic tissue surrounding a muscle.

Question 4

Perimysium

Answer 4

• sheath of connective tissue surrounding a bundle of muscle fibers

Question 5

Endomysium

Answer 5

a “wispy” (delicate and thin) layer of areolar connective tissue that surrounds each individual myocyte (muscle fiber, or muscle cell). It also contains capillaries and nerves.

Question 6

Muscle Fiber

Answer 6

the term often used in place of a “myocyte”…. Meaning a muscle cell.

Question 7

What is the purpose of mysium layers

Answer 7

helps reduce frictional wear and tear as muscle cells contract and relax repeatedly

Question 8

Fusiform

Answer 8

muscles that are tapering at both ends; spindle-shaped.

Question 9

Parallel

Answer 9

characterized by fascicles that run parallel to one another. Contraction of these muscle groups acts as an extension of the contraction of a single muscle fiber.

Question 10

Triangular

Answer 10

a flat muscle band with a broad origin and narrow insertion. Shaped like a “paper fan*”.

Question 11

Unipennate

Answer 11

type of pennate muscle wherein the muscle fibers or fascicles are all in one side of the tendon.

Question 12

Bipennate

Answer 12

a type that has two rows of muscle fibers, facing in opposite diagonal directions, with a central tendon, like a feather. This allows greater power but less range of motion in the muscle group.

Question 13

Multipennate

Answer 13

muscles having the fibers arranged at multiple angles in relation to the axis of force generation.

Question 14

Circular

Answer 14

muscles that typically encircle an orifice or object.

Question 15

First class lever

Answer 15

Fulcrum in the middle, load on one end, and effort on the other end. Ex: a pair of scissors

Question 16

Second Class Lever

Answer 16

fulcrum at one end, load is centrally placed, and effort is at the other end.
Ex: wheelbarrow

Question 17

Third class lever

Answer 17

fulcrum is at one end, load at the other end, and effort is in the center
Ex: biceps curl

Question 18

Platysma

Answer 18

sheet of muscle tissue that attaches along the mandible and then extends out far across the upper thoracic region. Can get looser over time if not toned

Question 19

contraction of frontalis results is

Answer 19

raising eyebrows and forehead

Question 20

Emil Heinrich Du Bois-Reymond

Answer 20

demonstrated neuromuscular junction through electrical currents

Question 21

Striations are visible in what muscle types

Answer 21

skeletal and cardiac

Question 22

what are the two types of muscle fibers

Answer 22

actin fibers (thin filaments) and myosin fibers (thick filaments).

Question 23

Why do individual muscle cell fibers have multiple nuclei?

Answer 23

because the extra nuclei enhance protein organization and production in muscle cells

Question 24

Dystrophin protein function

Answer 24

connects the border of the cluster of thick and thin filaments with the PLB and is important functionally because as the thin and thick filaments enact contraction

Question 25

most common type of muscular dystrophy

Answer 25

Duchenne's Muscular dystrophy

Question 26

H-zone

Answer 26

the space between columns of actin fibers.

Question 27

Z-disc

Answer 27

region which is the connections that form between two columns of actin fibers and forms an architectural fiber network to position and arrange the actin fibers

Question 28

I-band

Answer 28

region which is the space between columns of myosin fibers

Question 29

A-band

Answer 29

region which represents the span of a column of myosin fibers.

Question 30

M-line

Answer 30

region which represents architectural fibers that position and arrange the myosin fibers.

Question 31

Titin (elastic) Filaments

Answer 31

allow the distal ends of the myosin a point of attachment to the architecture of the “Z-disc

Question 32

how is a myosin filament formed?

Answer 32

The myosin molecule actually has two heads (as shown) and two tail regions that “twist together”. Many, many myosin molecules will join together to form a single thick filament

Question 33

Tropomyosin

Answer 33

The thin filament (actin filament) is actually shown to be two separate strands of actin molecules (shown as the blue beads) that “twist together”. These actin “beads” are organized by the long “spaghetti-like” strand

Question 34

What is the neuromuscular junction?

Answer 34

a living tissue connection between the nervous system and the muscular system.

Question 35

What is the primary neurotransmitter in the neuromuscular junctions formed with skeletal muscle.

Answer 35

acetylcholine

Question 36

T- tubules and terminal cisterns of SR store what?

Answer 36

calcium ions

Question 37

latent period

Answer 37

the period of time between when the stimulus is received and the muscle begins to generate tension.

Question 38

muscle contraction steps

Answer 38

1. NMS releases Ach 2. Ach causes movement of Na+ and K+ 3. Na + K cause the SR to release Ca+ to myofibrils 4. ATP is used for muscle contraction

Question 39

Period of Contraction

Answer 39

myofibrils are actively contracting

Question 40

period of relaxation

Answer 40

when myofibrils are relaxing or elongating again

Question 41

T or F: different muscles repsond differently when stimulated

Answer 41

T

Question 42

Muscle Twitch

Answer 42

the stimulus allows for the muscle to contract and then to fully relax prior to it being stimulated again.

Question 43

Muscle Summation

Answer 43

the additive effect of multiple stimulations of the NMJ of the muscle tissue where there is NOT enough time between stimuli for the muscle to completely relax

Question 44

Tetanus

Answer 44

the muscle reaches a point of maximal contraction and will stay “locked” in that peak of contraction for as long as there is stimuli being received at the NMJ.

Question 45

Isotonic

Answer 45

visible change in length

Question 46

isometric

Answer 46

no physical change but still doing work

Question 47

Slow Twitch Muscle Fibers

Answer 47

-large # of mitochondria -aerobic -good fatigue resistance -red color -moderate glycolysis -abundant capillaries

Question 48

Fast Twitch Muscle Fibers

Answer 48

-Fast glycolic -don't have many mitochondria -store high energy molecule (glycogen) -white/pink in color

Question 49

ratio of fast/slow twitch muscles for males

Answer 49

45% slow to 55% fast

Question 50

Increased contractile force

Answer 50

strength

Question 51

increased contractile velocity

Answer 51

speed

Question 52

increased contractile duration

Answer 52

longevity of answers

Question 53

what does weightlifting do?

Answer 53

increases size of muscle fibers

Question 54

stretching does what?

Answer 54

can lengthen muscle so it can contract fully

Question 55

Myasthenia Gravis

Answer 55

autoimmune disorder that causes debilitating effects due to the immune responses of the body attacking neuromuscular junctions, thereby damaging the ability of the brain and other aspects of the nervous system to regulate and control the muscular system cells.