WEEK 5 - muscle physiology

Question 1

what is the structure function breakdown of the muscle ?

Answer 1

• muscle
• mundle of muscle fibers
• single muscle fiber (cell)
• myofibril
• sarcomere

Question 2

where is the muscle fiber ?

Answer 2

in the muscle belly

Question 3

where do muscle fibrils run ?

Answer 3

throughout the whole length (is the contracting unit)

Question 4

TRUE OR FALSE

muscle fibre = muscle cell

Answer 4

TRUE

Question 5

TRUE OR FALSE

muscle fibers have the same functional parts of the muscle cell

Answer 5

TRUE

Question 6

what are the parts of the sarcomere ?

Answer 6

• thick and thin filament
• z-disk
• a-band
  -I-band

Question 7

what do crossbridges allow ?

Answer 7

allows muscle to change length (amount go overlap either increases or decreases) ; shortening or lengthening

Question 8

what are the stricture function steps of the skeletal muscle ?

Answer 8

→ crossbridge binds → crossbridge rotates → crossbridge unbinds → crossbridge resets

Question 9

what does each crossbridge contain ?

Answer 9

• 1 ATP
• 3.4 pN force
• 10nm length change

Question 10

define muscular strength :

Answer 10

force a muscle or muscle group can exert in one maximal effort

Question 11

define muscular endurance :

Answer 11

ability of muscles or muscle groups to perform repeated or sustained contractions

Question 12

what is muscular strength determined by ?

Answer 12

muscle size and neural drive

Question 13

what does bigger muscle = ?

Answer 13

more crossbridges

Question 14

what does more crossbridges = ?

Answer 14

more force

Question 15

what is muscle endurance determined primarily by ?

Answer 15

• increased capillarization (more blood flow)
• increased mitochondria dir density/function

Question 16

what does endurance do ?

Answer 16

maintain those muscle contractions (need oxygen; provides the muscle with ATP) ; how well can we utilize oxygen to make ATP

Question 17

what does increased mitochondria density / function lead to ?

Answer 17

• increased ATP
• increased crossbridges
• increased density

Question 18

what is contractile function of muscle dependent on ?

Answer 18

fiber type

Question 19

in humans, what are skeletal muscle characterized by ?

Answer 19

fast and slow twitch muscle fibers

Question 20

what are the two types of fast (type 2) :

Answer 20

• type IIx (fastest)
• type IIa (fast)

Question 21

define the fatigue resistance of type I (slow) :

Answer 21

high

Question 22

define the fatigue resistance of type IIa :

Answer 22

moderate

Question 23

define the fatigue resistance of type IIx :

Answer 23

low

Question 24

define the ATPase activity of type I (slow) :

Answer 24

low

Question 25

define the ATPase activity of type IIa :

Answer 25

high

Question 26

define the ATPase activity of type IIx :

Answer 26

high(er)

Question 27

define the contraction speed of type I (slow) :

Answer 27

slow

Question 28

define the contraction speed of type IIa :

Answer 28

moderately fast

Question 29

define the contraction speed of type IIx :

Answer 29

fast

Question 30

define the mitochondria density of type I (slow) :

Answer 30

high

Question 31

define the mitochondria density of type IIa :

Answer 31

moderate

Question 32

define the mitochondria density of type IIx :

Answer 32

low

Question 33

define the myoglobin of type I (slow) :

Answer 33

high

Question 34

define the myoglobin of type IIa :

Answer 34

moderate

Question 35

define the myoglobin of type IIx :

Answer 35

low

Question 36

define the force output of type I (slow) :

Answer 36

low

Question 37

define the force output of type IIa :

Answer 37

moderate

Question 38

define the force output of type IIx :

Answer 38

high

Question 39

FILL IN THE BLANK slow muscles has (greater or lesser) capillary and mitochondrial density, which supports aerobic metabolism and (improves or fails) fatigue resistance ?

Answer 39

greater & improves

Question 40

FILL IN THE BLANK replacement of contractile tissue with non-contractile material (mitochondria, capillary, etc) decrease _____ ___________

Answer 40

force potential

Question 41

talk about the "tale of two breasts: chicken vs duck" :

Answer 41

- despite having a similar build and size, the two animals preform different - duck = more red (high myoglobin content) - duck = slow twitch (endurance) - chicken = fast twitch (sprint) - duck = 8 hrs, 800 miles - chicken = 13 secs, 300 ft

Question 42

what are the two ways tissues can grow ?

Answer 42

hypertrophy and / or hyperplasia

Question 43

what is hypertrophy ?

Answer 43

increase in the size of individual muscle fibers

Question 44

what is hyperplasia ?

Answer 44

increase in the number of muscle fibers

Question 45

between hypertrophy and hyperplasia, which is more difficult to grow # of cells ?

Answer 45

hyperplasia

Question 46

FILL IN THE BLANK predominance (>95%) of muscle growth attributed to _________

Answer 46

hypertrophy

Question 47

how is muscle growth accomplished (in regards to anatomy) ?

Answer 47

accomplished with an increased number of myofibrils per fiber

Question 48

TRUE OR FALSE tissues can grow through hypertrophy and / or hyperplasia

Answer 48

TRUE

Question 49

what is hypertrophy ?

Answer 49

increase in the size of individual muscle fibers

Question 50

what is hyperplasia ?

Answer 50

increase in the number of muscle fibers

Question 51

what are amino acids that are delivered to the muscle used to form ?

Answer 51

amino acids delivered to muscle are used to form muscle proteins that comprise new myofibril s

Question 52

what is the myonuclear domain theory ?

Answer 52

each nucleus of a muscle cell is responsible for a finite volume of cell space

Question 53

in order for a muscle fiber to grow (hypertrophy), what much increase ?

Answer 53

the number of nuclei needs to increase

Question 54

what are satellite cells ?

Answer 54

quiescent cells that activate and enter the fiber myogenic stem cells responsible for muscle regeneration throughout the lifespan

Question 55

what do satellite cells aid in ?

Answer 55

aid in tissue repair

Question 56

what do satellite cells donate ?

Answer 56

their nuclei

Question 57

TRUE OR FASE satellite cells are similar to stem cells ?

Answer 57

TRUE

Question 58

what is the stimulus of muscle growth ?

Answer 58

exercise

Question 59

what is the adaptation of muscle growth ?

Answer 59

- muscle protein synthesis generates new myofibrils within existing fibers (muscle hypertrophy) - satellite cells proliferate and differentiate to form new nuclei to support cell processes of now bigger fibers

Question 60

what does muscle respond (in specific ways) in response to ?

Answer 60

overload

Question 61

what do muscle growth stimulus responds to ?

Answer 61

- metabolic accumulation - mechanical forces - immune signalling (inflammation)

Question 62

what is muscular strength based on ?

Answer 62

muscle size and activation

Question 63

what is muscular endurance based on ?

Answer 63

capillary and mitochondria density

Question 64

FINISH THE SENTENCE ... muscles adapt to exercise stimulus by _________________________________

Answer 64

generation of myofibril muscle protein and satellite cell differentiation into nuclei

Question 65

what are muscle adaptation stimulated by ?

Answer 65

accumulation of metabolites, detection of mechanical forces and inflammation