Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pathophysiology PH1002 > Muscle contraction > Flashcards

Muscle contraction Flashcards

1
Q

what are the 3 actions proteins are responsible for

A

contractile proteins, regulatory proteins, structural proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are contractile proteins

A

myofibrils- myosin and actin, myosin binds to actin allowing thin filaments to slide between the tick filaments during muscle contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are regulatory proteins

A

they turn contractions on and off, troponin and tropomyosin- under resting condition covers up the binding sites on the actin protein- prevents binding, for contraction to occur these 2 proteins need to move position (allowing binding)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are structural proteins

A

they provide alignment, elasticity, and extensibility to the sarcomere,e.g. TITIN, myomesin, nebulin and dystrophin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

proteins of the muscle- myosin

A

thick filaments are composed of myosin, each molecule resembles to golf clubs twisted together, they are held in place by the M line proteins, the tail binds to other myosin molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is the head of myosin made off

A

it is made of 2 globular protein subunits, reaches the nearest thin filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what happens to myosin during contraction

A

myosin heads interact with actin filaments, forming cross bridges- head pivots, producing motion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

proteins of the muscle- actin

A

thin filaments are made of actin, ropin and tropomyosin, binding site on each actin molecules is covered by tropomyosin in relaxed muscle, prevents binding of myosin ,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the first stage of contraction

A

the first stage of contraction is for calcium ions to bind to troponin, causing troponin and tropomyosin to move away, allowing cross bridges to for

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what holds the thin filaments in place

A

they are held in place by Z lines, from one Z line to the next is a sarcomere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

proteins of the muscle- titin

A

this anchors thick filaments to the M line and the Z discs, the portion of the molecule between the Z discs and the end of the thick filament can stretch up to 4 times its resting length, and spring back, unharmed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

titin role in muscle contraction

A

role in recovery of muscle from being stretched, therefore important in eccentric muscle contractions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

other structural proteins- m line

A

myoemsin protein, connects to titan and adjacent thick filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

other structural proteins- nebulin

A

it is an inelastic protein helps to align thin filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

other structural proteins- dystrophin

A

links thin filaments to sarcolemma and transmits tension generated to the tendon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

sliding filament mechanism of contraction- 1

A

myosin cross bridges pull on thin filaments, thin filaments slide inwards towards the M line, between thick filament, z discs move closer together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

sliding filament mechanism of contraction- 2

A

sarcomere shortens. the muscle fibre/ muscle shortens , thick and thin filaments do not change in length- width of A band stays the same

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is the contraction cycle

A

repeating sequence of events that causes the thin filaments to slide between thick filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

steps of contraction cycle

A

exposure of active sites, ATP hydrolysis into ADP and Pi, attachment of myosin to actin forming cross bridges, power stroke- pivoting of the myosin, pulling the thin filaments, detachment of myosin and actin, reactivation of myosin

20
Q

how long does the contraction cycle go on for

A

cycle keeps repeating as long as there is ATP available and high Ca+ level nera thin filament

21
Q

Stages of contraction cycle- 1

A

nerve impulses arrives at axon terminal motor neuron and triggers release of acetylcholine (ACh)

22
Q

Stages of contraction cycle- 2

A

Ach diffuses across synaptic cleft, binds to its receptors in the motor end plate, and triggers a muscle action potential

23
Q

Stages of contraction cycle- 3

A

acetylcholinesterase in synaptic cleft destroys ACh so another muscle action potential does not arise unless moreAch is released from the motor neuron

24
Q

Stages of contraction cycle- 4

A

muscle AP travelling along T tubule opens Ca2+ release channels in the sarcoplasmic reticulum membrane which allows calcium ions to flood into the sarcoplasm

25
Q

Stages of contraction cycle- 5

A

Ca2+ binds to troponin on the thin filaments, exposing the binding site for myosin.

26
Q

Stages of contraction cycle- 6

A

contraction: power strokes use ATP; myosin head bind to actin, swivel, and release: thin filaments are pulled toward center of sarcomere

27
Q

Stages of contraction cycle- 7

A

Ca2+ release channels in SR close and Ca2+ active transport pumps use ATP to restore low level of calcium ions in sarcoplasm

28
Q

Stages of contraction cycle- 8

A

troponin- tropomyosin complex slides back into position where it blocks the myosin binding sites on actin

29
Q

steps of relaxation- 1

A

acetylcholinesterase (AChE) breaks down ACh within the synaptic cleft, muscle action potential increases

30
Q

steps of relaxation- 2

A

Ca+ release channels close, Ca+ detaches from troponin

31
Q

steps of relaxation- 3

A

active transport pumps Ca+ back into storage in the terminal cisternae of the sarcoplasmic reticulum, Ca+ concentration falls

32
Q

steps of relaxation- 4

A

calcium binding protein (calsequestrin) helps hold cA+in the SR, tropomyosin- troponin complex recovers binding site on the actin molecules

33
Q

steps of relaxation- 5

A

contraction ends, relaxation occurs, muscle returns passively to resting length

34
Q

Optimal length of muscle fibre

A

optimal overlap of thick and thin filaments, produces greatest number of cross bridges and greatest amount of tension

35
Q

Past optimal length of muscle fibre

A

as stretch muscle (past optimal length), fewer cross bridges exist and less force is produced

36
Q

under optimal muscle fibre length

A

if muscle is overly shortened (less than optimal), fewer cross bridges exist and less force is produced, thick filaments crumpled by Z discs

37
Q

Normal length of muscle fibre

A

resting muscle length remains between 70-130% of optimal length

38
Q

what is the length of tension curve

A

graph of force of contraction (tension) versus length of sarcomere

39
Q

length of tension curve explained

A

optimal overlap at the top of the graph, when the cell is too stretched and little force is produced, when the cell is too short, little force is produced- sarcomere cannot shorten any further- no power stroke

40
Q

what is ATP used for in cells

A

it supplies energy for muscle contraction and the active transport of calcium ion pumps in the sarcoplasmic reticulum

41
Q

3 sources of ATP production within the muscle

A

creatine phosphate, anaerobic cellular respiration, aerobic cellular respiration

42
Q

what is excess ATP convert to

A

excess ATP within resting muscle used to form creatine phosphate

43
Q

what is creatine phosphate

A

CP 3-6 times more plentiful than ATP within muscle, it is quickly broken down provides energy for creation of ATP , it sustains maximal concentration for 15 secs

44
Q

anaerobic cellular respiration

A

ATP produced from glucose breakdown into pyruvic acid during glycolysis, if no O2 is present, pyruvic converted into lactic acid which diffuses into blood

45
Q

how long can glycolysis provide energy for

A

glycolysis can continue to anaerobically tO provide ATP for 30-40 seconds for maximal activity

46
Q

What is aerobic cellular respiration

A

ATP for any activity lasting longer than 30 seconds, if sufficient oxygen is available, pyruvic acid enters the mitochondria to generate ATP, water and heat, fatty acids and amino acids can also be used by the mitochondria

47
Q

What does the aerobic cellular respiration provide energy for

A

it provides 90% of ATP energy if activity lasts more than 10 minutes

Pathophysiology PH1002 (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions