Week 8-Muscular Tissue

Question 1

Functions of Skeletal Muscle

Answer 1

1) Move the body
2) Maintain posture
3) Protect and support
4) Regulate elimination of materials
5) Produce heat

Question 2

Characteristics of Skeletal Muscle

Answer 2

1) Excitability
2) Conductivity
3) Contractility
4) Extensibility
5) Elasticity

Question 3

Excitability

Answer 3

Ability of cell to respond to stimulus

Question 4

Conductivity

Answer 4

Involves electrical signal that is propagated along the plasma membrane as voltage gated channels open sequentially during an action potential

Question 5

Contractility

Answer 5

Enables muscle cells to cause body movement and to perform other functions (contractile proteins within skeletal muscle slide past one another)

Question 6

Extensibility

Answer 6

Lengthening of muscle cell

Question 7

Elasticity

Answer 7

Ability of muscle cell to return to original length following either shortening or lengthening of muscle

Question 8

Gross Anatomy of Skeletal Muscle

Answer 8

Skeletal muscles fibers, connective tissue layers, blood vessels, and nerves

Question 9

Fascicle

Answer 9

Bundles of muscle fibers

Question 10

Three Layers of Connective Tissue Components

Answer 10

1) Epimysium
2) Perimysium
3) Endomysium
-together they extend past muscle fibers to form tendon or aponeurosis

Question 11

Epimysium

Answer 11

-Layer of dense irregular connective tissue that surrounds the whole skeletal muscle
-Provides protection and support

Question 12

Perimysium

Answer 12

-Layer of dense irregular connective tissue around each fascicle
-Protection and support to bundles of muscle fibers

Question 13

Endomysium

Answer 13

-Areolar connective tissue that surrounds each muscle fiber
-Electrically insulate muscle fibers

Question 14

Tendon

Answer 14

Cordlike structure composed of dense regular connective tissue that connects muscle to bone

Question 15

Aponeurosis

Answer 15

Thin, flattened sheet of dense regular connective tissue that connects muscle to skeletal component (bone/ligament) or to fascia

Question 16

Deep fascia

Answer 16

-Expansive sheet of dense irregular connective tissue that is external to epimysium
-Separates individual muscles, binds muscles with similar functions, and fills spaces between muscles
-contains nerves, blood vessels, and lymph vessels

Question 17

Superficial fascia

Answer 17

Areolar and adipose tissue that separates muscle from skin

Question 18

End-plate Potential

Answer 18

Minimum voltage change that can trigger opening of voltage gated channels in sarcolemma to initiate action potential

Question 19

Action potential

Answer 19

Depolarization and repolarization

Question 20

Refractory period

Answer 20

-Period of time that includes depolarization and repolarization
-muscle cannot be restimulated during this time

Question 21

Triad

Answer 21

T tubule flanked by terminal cisternae of sacroplasmic reticulum

Question 22

Changes to Sarcomere During Contraction

Answer 22

-H zone disappears
-I band narrows in width and may disappear
-Z discs move closer

Question 23

Sliding filament theory

Answer 23

Repetitive movement of thin filaments sliding past thick filaments

Question 24

Oxygen Debt

Answer 24

Amount of additional oxygen that is consumed following exercise to restore pre-exercise conditions

Question 24

Oxygen Debt

Answer 24

Amount of additional oxygen that is consumed following exercise to restore pre-exercise conditions

Question 25

Power

Answer 25

Related to diameter of muscle fiber (large diameter=more powerful)

Question 26

Speed

Answer 26

Slow or fast genetic variant of myosin ATPase

Question 27

Fast twitch fibers

Answer 27

-have fast variant of myosin ATPase -initiate contraction faster and contraction is shorter

Question 28

Slow twitch fibers

Answer 28

-have slow variant of myosin ATPase -initiate contraction slower and contraction is longer

Question 29

Oxidative fibers

Answer 29

-provide ATP by aerobic respiration -extensive capillary network, many mitochondria, lots of myoglobin (gives them red color) -fatigue resistant

Question 30

Glycolytic fibers

Answer 30

-provide ATP by glycolysis -less extensive capillary network, fewer mitochondria, less myoglobin -white color -fatigable

Question 31

Muscle Tension

Answer 31

Force generated when skeletal muscle is stimulated to contract

Question 32

Muscle Twitch

Answer 32

A single, brief contraction period and then relaxation period of skeletal muscle in response to a single stimulation

Question 33

Threshold

Answer 33

Minimum voltage needed to stimulated muscle to generate a twitch

Question 34

Recruitment

Answer 34

Increase in muscle tension that occurs with an increase in stimulus intensity

Question 35

Wave/Temporal Summation

Answer 35

Stimulation occurs so rapidly that complete relaxation of skeletal muscle does not occur before next stimulation event (summation of contractile forces)

Question 36

Incomplete tetany

Answer 36

-further increases in stimulation frequency allows less time for relaxation between contraction cycles -Tension tracing continues to increase and distance between waves decreases

Question 37

Tetany

Answer 37

Continuous contraction

Question 38

Fatigue

Answer 38

A decrease in muscle tension that occurs from repetitive stimulations

Question 39

Muscle Tone

Answer 39

Resting tension in skeletal muscle generated by involuntary somatic nervous stimulation of muscle

Question 40

Resting Muscle Tone

Answer 40

Random contraction of small numbers of motor units causes muscle to develop tension

Question 41

Isometric contraction

Answer 41

Skeletal muscle tension is insufficient to overcome resistance and there is no movement of muscle

Question 42

Isotonic contraction

Answer 42

Skeletal muscle tension results in movement of muscle

Question 43

Concentric contraction

Answer 43

Shortening of muscle length

Question 44

Eccentric contraction

Answer 44

Lengthening of muscle

Question 45

Length-tension relationship

Answer 45

Amount of tension a skeletal muscle can generate when stimulated is influences significantly by amount of overlap of thick and thin filaments within muscle fibers when muscle begins its contraction