Brainscape's Knowledge GenomeTM

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


See full index

BRS > MSK - muscle microstructure and contraction > Flashcards

MSK - muscle microstructure and contraction Flashcards

1
Q

What muscles are under involuntary control?

and which system controls it?

A

Smooth muscles from autonomic nervous sysm

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

What is special about cardiac muscle?

A

can contract autonomously

but under influence of autonomic nervous system and chemicals

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

What muscles are under voluntary control?

What are there function?

A

skeletal muscles

attach bones to contract and bring about movement

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

Where are smooth muscles found?

A muscles eyes

B airways

C biceps

A

B

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

Which system control skeletal muscles

A

somatic nervous system

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

What are 3 connective tissue surronding each level of muscle tissue?

What do they surrond?

A

enodmysium - surrond a single muscle fibre

perimysium - surronds fascicles (multiple fibres of muscle)

epimysium - surronds entire muscle

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

Label diagram of muscle

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

What is muscle fibre compose of?

A

myofibrils

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

What is difference between myofibre and microfibril

A

myofibre - a muscle fibre, multinucleated muscle cell

myofibrils - Cylindrical organelles, found within muscle cells, that are the contractile unit of muscles.

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

What are 5 may components of skeletal muscle?

A

covered by plasma membrane - sarcolemma

T-tubules - tunnel into centre

sacroplasm - cytoplasm

network of fuild filled tubules - sacroplasmic reticulum

myofibrils

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

label this diagram of muscle fibre

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

Where are myoblobin and mitochondria found in muscle cell?

A

sacroplam

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

What is the ‘thin’ and ‘thick’ filament?

A

thin - actin

thick - myosin

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

Where are 2 types called and located on this diagram?

A

H disk and Z disk

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

do myofilaments extend along length of myofibres?

A

NO but they overlap arranged and in compartments (sarcomeres)

myfilaments are the protiens myosin and actin, they END

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

Do myofibrils extend along myofibres

A

YEs

composed of 2 main type of potiens - actin and myosin

is long line of repeating sacromeres

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

What seperates sacromeres

A

Z discs

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

What is A band

A

Where myosin is found

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

What is strucutre of myosin?

A

thickkk - golg clubs

2 globular heads

single tail formed from 2 alpha helices

tails of hundreds molecules form one filament

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What strucutre of actin?

A

twisted into helix

each molecule has actin binding site

contains troponin and troponmysoin

21
Q

Label this diagram of actin

A
22
Q

What happens to A band, I band and H zone when contraction?

A

A same length - length of myosin

I band decreases

H zone narrows or disappears

23
Q

Steps of intiation of muscle contraction?

A

phase 1: AP open voltage Ca2+ channels, Ca2+ enter pre-synpathic terminal, release of Acetylcholine binds to receptors + AP in muscle

Phase2:

  1. AP spread around surface membrance

Acetylcholine broken down by acetylcholine esterase, response stop

24
Q

What is mechanism of actual muscle contractions

A

1) . action propagates into T-tubules
2) . DHP receptor in T sense chnage + change/opens ryanodine receptor in SR
3) . Ca2+ released from SR into space around filaments (actin and myosin)
4) . Binds to troponin and tropomypson moves
4) . Allows crossbridhes to attach to actin
5) . Ca2+ actively transported into continously while AP continue. uptake less than or equal to release rate

25
Q

How exactly does myosin head couple to actin?

A

1) . Ca2+ causes troponin to move from tropomyosin chain
2) . exposes myosin binding sire on actin chain
3) . ‘charged’ myosin heads bind to exposed site on actin
4) . discharge of ADP causes ‘power stroke’ pulling actin towards centre of sarcromere
5) . ATP binding releases myson head from actin
6) . ATP hydrolysis energy ‘recharge’ myosin head

26
Q

What nervous pathway for muscle contraction?

A

upper motor neurone in brain

to lower motor neurone brainstem/spinal cord

27
Q

How does the nerves innervates muscles

A

single neurone innervates many muscles fibres however all in the same motor unit

28
Q

What is a motor unit?

A

A single motor neuron all muscle fibres

when stimulated ALL muscle fibres in unit contract

29
Q

Can other nerves inverve a muscle fibre that is already innverated by another nerves?

A

NOO

only one motor innverates those fibres in that motor unit

30
Q

What controls the fine control?

A

each nerves innverates - less motor units and fibres

31
Q

What are 3 types motor units?

A

Slow, fast (fatigue resistant), fast fatiguable

32
Q

What are characteristics of slow motor units?

A

smallest diameter cell bodies

smalld endritic trees

thinnest axons

slowest speed

33
Q

What are characteristics of fast, fatigue resistant motor units?

A
34
Q

What are characteristics of Fast, fatiguable motor units?

A

larger diamter cell bodies

larger dentritic rrees

thicker axons

faster conducitivty

35
Q

How does each type of motor neurone appear?

A
36
Q

Properties of each of motor units?

A
37
Q

What are 2 mechanisms that brain regulated force a muscle can produce?

A

recruitment and rate coding

38
Q

How does recruitment work?

A

motors not randomly recruited

choosed based on size, small first (generally slow)

as more force more units

39
Q

What does recruitment allow for?

A

fine control - under which low force levels are required

40
Q

What is rate coding?

A

motor can fire at range of frequnecies

slow units at lower

as firing rate rate increase, force for each unit increasees

41
Q

What happens when rate coding too fast?

A

Summation - unit fire at frequency too fast to allow muscle relax between AP

42
Q

What is recruitment order of the type of muscles fibres?

A

slow then fast resistance then fast fatigue

43
Q

So overall what happens when as force increase when carrying item?

A

Increases firing rate for each muscle unit

more fibred recruited

44
Q

What are affects of neurotrophic factors?

A

prevent neuronal death and promote frowth after injury

changes characterisitic of muscle, effect on properties

45
Q

What does the motor unit and fibre type depend on? Or is it indepedendent if so how

A

dependent on type of nerve innvating it

if slow, muscle beocmes slow

46
Q

What are 3 types of muscle contraction?

A

isometric - no change in length of muscle

concentric- muscle shorterns as force/contraction

eccentric - muscle becomes longer, easily damaged, most force

47
Q

How could injury to pathology affect muscle units?

A

leads to type 1 converted to 11

48
Q

What affects microgravity have on fibres

A

slow to fast

49
Q

What affects do aging have on muscle units?

A

loss of type 1 and 2, more 11

so more slower, type 1 fibres in ages muscles

BRS (19 decks)

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