Muscle 2

Question 1

Describe what determines the length tension relationship

Answer 1

it is dependent on the actin and myosin overlap

Question 2

tension generated when all cross bridges are attached

Answer 2

Optimum force generated as all cross bridges are formed

Question 3

Increased length of sarcomere tension generated

Answer 3

tension has decreased generation as less cross bridge cycles are occuring

Question 4

decreased length of sarcomere

tension generated

Answer 4

generation of tension is decreased as areas of the myosin where their is no myosin head= decreased force

Question 5

sarcomeres completely overlap and meet the z disc

what tension is generated

Answer 5

no tension is generated as the actin begin to overlap which interfere with the myosin.

therefore no tension is generated

Question 6

equation for total tension

Answer 6

active + passive force

Question 7

What is passive tension

Answer 7

generated from the elastic forces which resist

Question 8

what are active tension

Answer 8

the length of the sarcomere

Question 9

what is a motor unit

Answer 9

motor neuron and all the muscle fibers it innervates

Question 10

describe ACH release into the neuromuscular junction

Answer 10

1. Action poetntial travels down the motor neuron
2. CA enters the axon via the axon terminals
3. ACh vesicles are triggered= exiting of the terminal membrane into the synaptic cleft

Question 11

Excitation contraction coupling part 1 sequence

Answer 11

1. ACh released into the synaptic cleft
2. Ach activation of the receptors
3. A muscle action potential is generated

Question 12

effects of ACh are short

what enzyme breaks it down

Answer 12

acetylcholine esterase

Question 13

Muscle action potential triggered

describe

(part 1 excitation contraction coupling)

Answer 13

1. enough ligand gated channels open= threshold
2. Voltage gated NA ions open= action potenital generated
3. AP is propagated throughout the sarcolema and into the T tubules

Question 14

state the sequence of part 2 excitation contraction coupling

Answer 14

1. Calcium is released from the SR

2. Ca binds with tropinin

Question 15

describe calcium released from the SR

Answer 15

1. AP travels down the sarcoelma into the T tubules

2. Voltage gated CA channels are activated in the SR and release CA into the muscle cytosol

Question 16

describe Calcium binding to Actin

Answer 16

if the calcium conc meets threshold Ca will bind to Tropinin and the cross bridge cycle will be able to occur

Question 17

What occurs after calcium binds to actin

Answer 17

CROSS BRDIGE CYCLE

Question 18

what occurs last within the excitation contraction coupling

Answer 18

Contraction ends when Ca conc falls

Question 19

describe Contraction ends when Ca conc falls

Answer 19

Ca is actively pumped back into the SR via the Ca2+ ATPase pump

Conc of CA decreases causing the myosin binding site to be covered by the tropomyosin

Question 20

Creatine Phosphate is activated when

Answer 20

acts as a ATP store

Creatine phosphate + ADP= creatine + ATP

Question 21

when is Creatine Phosphate used

Answer 21

anaerobic exercise

Question 22

Type 1 muscle fibres

Answer 22

slow efficient aerobic cells

Question 23

Type 2 muscle fibres

Answer 23

fast large fibers= great forces

Question 24

Regulation of force is dependent on what

Answer 24

rate of stimulation of individual motor unit

number of motor units recruited

Question 25

Increased frequency of action potential causes what

Answer 25

Temporal summation which is a grater force as the muscle is unable to relax= GREATER CONTRACTION

Question 26

which motor units are recruited first

Answer 26

fatigue resistant