Chapter 48: Musculoskeletal Systems

Question 1

skeletal muscle

Answer 1

responsible for all voluntary movements, and many involuntary actions

Question 2

cardiac muscle

Answer 2

responsible for the beating of the heart

Question 3

smooth muscle

Answer 3

creates movement in many hollow internal organs

under the control of the autonomic nervous system

Question 4

muscle fibers

Answer 4

skeletal muscle cells

large with many nuclei

Question 5

actin

Answer 5

thin filament, used for muscle contraction

Question 6

myosin

Answer 6

thick filament

Question 7

myofibrils

Answer 7

bundles of thick myosin and thin actin arranged in an orderly fashion

Question 8

sarcomeres

Answer 8

repeating units of overlapping filaments of actin and myosin.

Question 9

titin

Answer 9

largest protein in the body

runs right through a myosin bundle(from z line to z line)

Question 10

each sarcomere is bounded by

Answer 10

z line

Question 11

centered in the sarcomere is the..

Answer 11

a band, which contains all the myosin filaments

Question 12

H zone and I bands are..

Answer 12

regions where actin and myosin filaments do not overlap in the relaxed muscle

Question 13

tropomyosin

Answer 13

twisting around the actin chains

Question 14

troponin

Answer 14

attached to tropomyosin at intervals

Question 15

motor unit

Answer 15

a motor neuron and all of the fibers with which it forms synapses with

Question 16

sacroplasm

Answer 16

muscle fiber cytoplasm

Question 17

T tubules

Answer 17

system of transverse tubules

Question 18

twitch

Answer 18

the spread of an action potential through the muscle fiber’s T tubule system causes a minimum unit of contraction

Question 19

the strength of a muscle contraction depends on…

Answer 19

1. how many fibers are contracting

2. and at what rate

Question 20

tetanus

Answer 20

continuous activation of the contractile machinery.

Question 21

slow-twitch fibers

Answer 21

oxidative or red muscles
contain myoglobin
many mitochondria
well supplied with blood vessels

Question 22

fast-twitch fibers

Answer 22

glycolytic or white muscles
fewer mitochondria 
little to no myoglobin 
fewer blood vessels
look pale in comparison to slow-twitch fibers

Question 23

muscle ATP systems

Answer 23

immediate, glycolytic, and oxidative systems

Question 24

immediate system

Answer 24

uses performed ATP and creatine phosphate

Question 25

glycolytic system

Answer 25

metabolizes carbohydrates to lactate and pyruvate

Question 26

oxidative system

Answer 26

metabolizes carbohydrates or fats alllll the way to water and carbon dioxide

Question 27

hydrostatic skeletons

Answer 27

consists of a volume of fluid enclosed in body cavity surrounded by muscle

Question 28

cartilage

Answer 28

extracellular matrix that is tough, rubbery mixture of polysaccharides and proteins(mainly collagen)
supportive tissue

Question 29

bone

Answer 29

also contains collagen fibers

contains calcium phosphate crystals that give it rigidity and hardness

Question 30

osteoblast

Answer 30

lay down new matrix material on bone surface

Question 31

osteocyte

Answer 31

osteoblasts that get trapped by their own handiwork

Question 32

osteoclasts

Answer 32

cells that reabsorb bones

Question 33

membranous bone

Answer 33

forms on a scaffold of connective tissue membrane

Question 34

cartilage bone

Answer 34

forms first as a cartilaginous structure resembling the future mature bone, then gradually hardens, or ossifies, to become bone

Question 35

compact

Answer 35

solid and hard

Question 36

cancellous

Answer 36

having numerous internal cavities that make it appear spongy, although it’s rigid)

Question 37

Haversian systems

Answer 37

set of thin, concentric bony cylinders, between which are the osteocytes in their lacunae (small cavities)
narrow canal containing blood vessels and nerves running through the middle

Question 38

joints

Answer 38

where two or more bones come together

Question 39

flexor

Answer 39

the muscle that bends or flexes the joint

Question 40

extensor

Answer 40

the muscle that straightens or extends the joint

Question 41

ligaments

Answer 41

flexible bands of connective tissue

connect bones to bone

Question 42

tendons

Answer 42

attache the muscle to bone