Brainscape's Knowledge GenomeTM

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


See full index

MSK > Muscle physiology and histology > Flashcards

Muscle physiology and histology Flashcards

1
Q

What are the four levels found in a muscle?

A 
Whole muscle
Fascicle 
Muscle fibre 
Myofibril
Sarcomere
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What types of cells are found in the whole muscle?

A

Muscle fibres
Connective tissue
Blood vessels and lymph

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

What is a muscle fibre?

A

One muscle cell

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

Name three unique features of a muscle fibre.

A

Multinucleate
Contain myofibrils
Very long.

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

How big are muscle fibres?

A

10-100microM in diameter

1000-2000microM in length

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

What are myofibrils?

A

Collections of sarcomeres packaged together.

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

What is a sarcomere?

A

Basic functional unit of the muscle that allows for contraction.

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

What two proteins make up a sarcomere?

A

Myosin (heavy chain)

Actin (light chain)

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

What are the five regions of a sarcomere called and what do they represent?

A 
A Band- From one end of myosin to the other
I Band- Area w/ no myosin
H Zone- Area w/ no actin
Z Line- Area linking actin
M Line- Area linking myosin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the five stages of a muscle contraction?

A 
Resting
Binding- requires Ca2+
Bending- ADP+Pi dissociate 
Detachment- Fresh ATP binds
Energised- with ATP bound ready for next stroke
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does Ca2+ allow binding?

A

Binds to troponin to move it out the way allowing myosin to bind to tropomyosin on actin.

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

What is a muscle fascicle?

A

A collection of muscle fibres in found in the whole muscle.

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

What is the connective tissue round the whole muscle called?

A

Epimysium

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

What is the connective tissue around the fascicle called?

A

Perimysium

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

What is the connective tissue around a single muscle fibre called?

A

Endomysium

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

What are the three types of muscle fibres?

A

Type I
Type IIa
Type IIb

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

Describe Type I muscle fibres.

A

Aerobic red fibres with lots of mitochondria and myoglobin. Slow contracting but resistant to fatigue.

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

Describe Type IIa fibres.

A

Intermediate fibres. Relatively fast contracting but relatively fatigue resistant.

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

Describe Type IIb fibres.

A

Anaerobic white fibres with little mitochondria and myoglobin. Fast contracting but fatigue easily.

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

How many nerves synapse onto a singe muscle fibre?

A

One

21
Q

What is a neuromuscular unit?

A

An alpha motor neuron and all the muscle fibres it innervates.

22
Q

What is the neurotransmitter in somatic motor neurons?

A

ACh

23
Q

What ions does nAChR let through?

A

Na in and K out

24
Q

What is an EPP?

A

The sum of all the mepp caused by each quanta of ACh binding.

25
Q

How many ACh molecules does it take to open a nAChR?

A

Two

26
Q

Describe the presynaptic events that lead to ACh release.

A

An AP travels down the nerve fibre to the bouton where it activates VGCC allowing Ca in which allows for binding of ACh vesicles.

27
Q

Describe how ACh is recycled.

A

ACh is broken down by AChesterase to choline and acetate. Choline is reuptaken into the presynaptic cell where it is combined with acetyleCoA to form ACh.

28
Q

How does the EPP propagate a contraction?

A

It allows opening of VCSC to propagate the depol across the cell. This travels down the T-tubules to allow Ca2+ release from the SR.

29
Q

What two factors does the generation of muscle tension rely on?

A

Number of fibres recruited

Tension developed per muscle fibre.

30
Q

What three things determine the tension developed per muscle fibre?

A

Frequency of stimulation
Thickness of fibre
Length of starting contraction

31
Q

Is the length of contraction in skeletal muscle long or short?

A

Long

32
Q

What is summation of contraction?

A

When another AP arrives before the muscle has finished contracting and relaxing it can cause it to contract further thus generating extra force.

33
Q

What is tetanising a muscle?

A

When it is fully contracted and can contract no further.

34
Q

What is the maximal tetanic contraction?

A

The maximum length change for each muscle. This is described as 100% of its length. If it is shorter than this you won’t get full length contraction and longer won’t get full power.

35
Q

What are isotonic contractions?

A

Contractions used for body movement.

36
Q

What are isometric contractions?

A

Contractions used to fix an object in space.

37
Q

What are the origins of the two potential motor inputs to a muscle?

A

UMN and LMN from brain giving conscious control

Reflex arc of somatic sensory, interneuron and somatic motor.

38
Q

Describe the stretch reflex arc.

A

Resists passive change to the muscle length to maintain optimal muscle length. Important for walking. Muscle stretch activates stretch receptors thus causing reflex muscle contraction.

39
Q

What senses muscle stretch?

A

Muscle spindles/intrafusal fibres. Annulospiral fibres in them do the sensing.

40
Q

What are extrafusal fibres?

A

Normal muscle fibres

41
Q

Where are muscle spindles usually found?

A

In the middle of the muscle.

42
Q

How do they detect stretch?

A

Increase stretch causes increase discharge.

43
Q

What neurons synapse onto muscle spindles?

A

Gamma MN to adjust level of tension.

44
Q

What do ligaments do?

A

Attach bone to bone.

45
Q

What do tendons do?

A

Attach muscle to bone.

46
Q

Describe tendons.

A

Parallel collagen fibres
Type 1 Collagen 99%
Type 2 Collagen 1%

47
Q

Describe ligaments

A

Nearly parallel collagen fibres
Type 1 Collagen 90%
Type 2 Collagen 10%

48
Q

What are the four stages of tendons entering bone?

A

Parallel collagen fibres
Unmineralised fibrocartilage
Mineralised fibrocartilage
Cortical bone

49
Q

What are the five morphologies of skeletal muscle and give examples of them.

A 
Flat- External obliques
Fusiform- Biceps brachii
Circular- Orbicularis oculi
Pennate- Deltoid
Quadrate- Rectus abdominis.

MSK (17 decks)

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