Muscle

Question 1

Three types of muscle

Answer 1

Skeletal, cardiac, smooth

Question 2

Skeletal muscle

Answer 2

Striated, voluntary, attached to bone

Question 3

Smooth muscle

Answer 3

Not striated, involuntary, hollow organs

Question 4

Flexor muscle

Answer 4

Brings bones together

Question 5

Extensor muscle

Answer 5

Moves bones away

Question 6

Flexor and extensor muscles are

Answer 6

Antagonistic muscle groups

Question 7

Example of antagonistic muscle pair

Answer 7

Bicep (flexor), tricep (extensor)

Question 8

Muscle organization

Answer 8

Fiber –> muscle fascicle (bundle of fibers) –> skeletal muscle –> tendon

Question 9

Composition of skeletal muscle

Answer 9

Connective tissue, muscle fascicles, blood vessels, nerves

Question 10

Muscle fascicles

Answer 10

Composed of individual muscle fibers

Question 11

Sarcomere length

Answer 11

Z-disc to Z-disc

Question 12

Z discs

Answer 12

Attachment sites for thin filaments

Question 13

I bands

Answer 13

Lightest color bands, thin filaments only , divided by z disc

Question 14

A bands

Answer 14

Darkest bands, thick filaments with thin filament overlap

Question 15

H zone

Answer 15

Lightest region of A band, thick filaments only

Question 16

M line

Answer 16

Attachment of thick filaments, divides A band

Question 17

Contractile proteins

Answer 17

Myosin, actin

Question 18

Myosin

Answer 18

Thick filaments

Question 19

Actin

Answer 19

Thin filaments

Question 20

Contraction regulatory proteins

Answer 20

Tropomyosin, troponin

Question 21

Thick filament anatomy

Answer 21

Myosin heads, hinge regions, myosin tail

Question 22

Thin filament anatomy

Answer 22

Twisted chains of tropomyosin and g-actin molecules

Question 23

Nebulin

Answer 23

Inelastic proteins that align actin filaments

Question 24

Titin

Answer 24

Elastic proteins that stretch between M line and Z disc

Question 25

Function of sarcoplasmic reticulum

Answer 25

Stores Ca2+

Question 26

Contraction

Answer 26

Creation of tension in muscle, ATP dependent, shortening of sarcomere

Question 27

Contraction coupling

Answer 27

Ach release from motor neuron initiates action potential in muscle fiber which triggers calcium release from sarcoplasmic reticulum --> contraction

Question 28

Muscle twitch

Answer 28

Single contraction-relaxation cycle

Question 29

Fatigue

Answer 29

Reversible condition in which a muscle is no longer able to generate or sustain the expected output; central and peripheral

Question 30

Central fatigue

Answer 30

From CNS --> psychological, reflexes

Question 31

Peripheral fatigue

Answer 31

Fatigue at neuromuscular junction, excitation-contraction coupling, Ca2+ signaling --> decreased neurotransmitter release, change in membrane potential, Ca2+ leak channels, depletion of ATP

Question 32

Causes of muscle fatigue during extended submaximal exercise

Answer 32

Depletion of glycogen stores

Question 33

Causes of muscle fatigue during short duration maximal exertion

Answer 33

Increased levels of inorganic phosphate, slows Pi release from myosin, decrease calcium release

Question 34

Causes of muscle fatigue during maximal exercise

Answer 34

K+ leaves muscle fiber, leading to increased concentration that decreases Ca2+

Question 35

Muscle fiber types

Answer 35

Slow oxidative, fast oxidative-glycolytic, fast glycolytic

Question 36

Slow oxidative muscle fibers

Answer 36

High resistance to fatigue; smallest diameter, high capacity to generate ATP, red, slow consumption ATP

Question 37

Fast oxidative-glycolytic muscle fibers

Answer 37

Moderate resistance to fatigue; intermediate diameter, intermediate capacity to generate ATP, red-pink, fast consumption ATP

Question 38

Fast glycolytic muscle fibers

Answer 38

Low resistance to fatigue; low capacity to generate ATP, largest diameter, white, fast consumption ATP

Question 39

Rigor mortis

Answer 39

Metabolism stops, ATP supplies are exhausted --> actin and myosin cannot be released, muscles in state of contraction indefinitely

Question 40

Isotonic contraction

Answer 40

Create force, move load --> concentric and eccentric

Question 41

Isometric contraction

Answer 41

Create force, no movement --> shortening of sarcomeres without change in length (elastic elements stretch)

Question 42

Concentric action

Answer 42

Shortening

Question 43

Eccentric action

Answer 43

Lengthening

Question 44

Load-velocity relationship

Answer 44

More load = slower movement of muscle

Question 45

Which muscle type has the longest contractions

Answer 45

Smooth muscle

Question 46

Which muscle type uses less energy?

Answer 46

Smooth muscle

Question 47

Which muscle type maintains force for long periods?

Answer 47

Smooth muscle

Question 48

Which muscle type has low oxygen consumption?

Answer 48

Smooth muscle

Question 49

What controls smooth muscle?

Answer 49

Hormones, paracrines, neurotransmitters --> multiple pathways for contraction and relaxation

Question 50

Single vs. multi-unit smooth muscle cells

Answer 50

Single= no innervation, Multi-unit= innervation (with varicosity)

Question 51

Smooth muscle compared to skeletal

Answer 51

Smaller fibers, longer actin and myosin filaments, activity much slower, not arranged in sarcomeres, less sarcoplasmic reticulum

Question 52

Stretch-activated calcium channels

Answer 52

Open when pressure or other force distorts cell membrane, smooth muscle

Question 53

Smooth muscle control

Answer 53

Antagonistic control, dual innervation from parasympathetic and sympathetic