quiz 2

Question 1

sarcolemma

Answer 1

muscle cell membrane (surrounds myofibrils)

Question 2

sarcoplasm

Answer 2

cytoplasm of a cell
-glycogen storage, myoglobin, mitochondria

Question 3

tranverse tubules

Answer 3

carry action potential deep into muscle fiber

Question 4

sarcoplasmic reticulum

Answer 4

calcium storage

Question 5

myofibrils

Answer 5

functional contractile units of skeletal muscle
-constructed of many sarcomeres

Question 6

sarcomeres

Answer 6

basic contractile element of skeletal muscle -smallest unit within the muscle
-run end to end for full myofibril length

Question 7

actin

Answer 7

thin myofilaments

Question 8

3 proteins make up thin filaments

Answer 8

1. actin
2. troponin
3. tropmyosin

Question 9

troponin

Answer 9

binds to calcium released from SR
moves tropomyosin exposing myosin binding sites

Question 10

tropomyosin

Answer 10

covers myosin binding site on actin enabling muscle to relax when no SR CA2
-covers myosin binding site when calcium is within SR

Question 11

myosin

Answer 11

thick filamentt
-heads contain actin binding sites
-use atp to “ratchet”
-have ATPASE enzyme

Question 12

myosin is stabilized by

Answer 12

titin

Question 12

how does the muscle shorten

Answer 12

overlap is changing because of ratcheting
-z disc gets closer

Question 13

titin

Answer 13

stabilizes myosin and anchors myosin to Z line

Question 14

voluntary muscle contraction starts in ____ and requires

Answer 14

brain
-requires nervous system
-muscle cells
- interdependence

Question 15

motor unit

Answer 15

single alpha motor neuron and all the fibers it innervates
-more operating motor units = greater contractile force

Question 16

site of communication between neuron and muscle
and consists of synapse between a motor neuron and muscle fiber

Answer 16

NMJ

Question 17

excitation coupling step 1

Answer 17

action potential starts in brain and moves along spinal cord

Question 18

which 2 pumps require ATP

Answer 18

NA - K pump and CA pump

Question 19

excitation coupling step 2

Answer 19

Ap travels along a single motor neuron towards NMJ

Question 20

excitation coupling step 3

Answer 20

AP arrives at NMJ causes release of acetylcholine

Question 21

excitation coupling step 4

Answer 21

ACH crosses synapse, binds to ACH receptors on plasemalemma

Question 22

excitation coupling step 5

Answer 22

AP travels down sarcolemma and into t-tubules as they appear

Question 23

excitation coupling step 6

Answer 23

AP inside t-tubules, triggers CA release from Sarcoplasmic reticulum
- then goes to bind to troponin

Question 24

excitation coupling step 7

Answer 24

released CA enables actin - myosin contraction -CA binds to troponin that causes tropomyosin to uncover myosin binding sites -myosin binds to newly uncovered binding sites on actin and ratchets

Question 25

cross-bridge cycling (actin myosin contraction) step 1

Answer 25

myosin heads are energized but muscle is relaxed - myosin atpase has created energy

Question 26

cross-bridge cycling (actin myosin contraction) step 2

Answer 26

cross bridge froms upon binding site uncovering

Question 27

cross-bridge cycling (actin myosin contraction) step 3

Answer 27

myosin head ratchets using the energy described above

Question 28

cross-bridge cycling (actin myosin contraction) step 4

Answer 28

myosin head binds new ATP causes release of Actin

Question 29

cross-bridge cycling (actin myosin contraction) step 5

Answer 29

myosin atpase breaks atp down energizing myosin head

Question 30

cross-bridge cycling (actin myosin contraction) step 6

Answer 30

If CA Is still present the myosin head binds to another actin site further down to increase shortening

Question 31

is their calcium in a relaxed muscle

Answer 31

no

Question 32

tropomyosin is covering binding sites when muscle is __

Answer 32

relaxed

Question 33

what causes SR to release CA into sarcoplasm

Answer 33

AP

Question 34

type 1 muscles

Answer 34

slow twich -oxidative -fatigue resistant -more mito - krebs and ETC -slower ATP ase -less developed SR -slower speed of contraction

Question 35

type 2 muscles

Answer 35

white, fast twitch -fast glycolitic -more glycolitic enzymes -fewer mito -faster ATP generation -higher phosphocreatine and creatine kinase -more developed SR

Question 36

which type has higher oxidative capacity

Answer 36

type 1

Question 37

what fuel is best for type 1

Answer 37

fat

Question 38

what fuel is best for type 2

Answer 38

glucose

Question 39

fuel mix

Answer 39

1. motor recruitment 2. stress hormone 3. CHO availability