Brainscape's Knowledge GenomeTM

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


See full index

MSK > Physiology > Flashcards

Physiology Flashcards

1
Q

Isometric contraction is?

A

if the muscle tension changes but length stys the same (i.e. carrying a heavy dumbell.)

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

Isotonic contraction is?

A

if length changes but tension stays the same (i.e. body movment.

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

Muscles within a motor unit can be of different types

A

F

they all have to be the same type of fibre

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

Motor units all have the same number of muscle fibres

A

F

this varies

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

What is a motor unit made up of?

A

motor neuron and the skeletal muscle fibers innervated by that motor neuron’s axonal terminals.

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

three types of muscles in the human body

A

Smooth
Skeletal
Cardiac

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

skeletal and cardiac muscles are - muscles; and skeletal muscle is subjected to - control

A

striated

voluntary

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

skeletal muscle contraction is initiated by - - stimulation

A

motor neuron

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

number of muscle fibres (cells) per motor unit depends on?

A

the function served by the muscle

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

muscles which serve fine movements (e.g. external eye muscles) have -
fibres per motor unit

A

fewer

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

What is the summary of the levels of organisation in skeletal muscle?

A 
Muscle organ made up of muscle fibres (myocytes), these are made up of many myofibrils. Sarcomere is functional unit within myofibril.
Contains Myocin (thick dark filament) Acrin (thin light filament)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a functional unit?

A

the smallest component capable of performing all the functions of that organ

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

The sarcomere is found between two - - , these connect the - filaments of 2 adjoining -

A

Z-lines, thin, sarcomeres

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

All of thick filament is

A

A band

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

area within middle of A-band where thin filaments don’t reach

A

H zone

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

Extends vertically down middle of A-band within the centre of H-zone

A

M line

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

Consists of remaining portion of thin filaments that do not project in A-band

A

I band

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

ATP is required for contraction only

A

F

contraction and relaxation

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

ATP is needed during muscle movement to:

A

It is split by myosin ATPase to power cross bridges during contraction

during relaxation to
release cross bridges
and pump Ca2+ back into SR

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

Ca2+ is entirely derived from sarcoplasmic reticulum in skeletal muscle

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Acetylcholine is the transmitter at the neuromuscular junction

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How can a stronger muscle contraction be achieved?

A

Motor unit recruitment: Stimulation of more motor units.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

asynchronous motor units recruitment during submaximal contractions helps prevent - -. Why?

A

Muscle fatigue

During continuous contractions, some units are firing while others recover, providing a built in recovery period.

24
Q

Tension developed by each contracting muscle fibre depends on?

A
  • Frequency of stimulation
  • Summation of contractions
  • Length and thickness of muscle fibre
25
Q

What is summation of contraction?

A

When a muscle fibre is restimulated before it can fully relax. This is a summation of muscle twitch.

26
Q

What is tetanus?

A

Sustained contraction - muscle has NO opportunity to relax between stimuli

27
Q

In skeletal muscle the duration of AP is the same as that of a muscle twitch

A

F

the duration of action potential is much shorter than the duration of resulting twitch

28
Q

It is possible to summate twitches
to bring about a stronger contraction through
repetitive fast stimulation of skeletal muscle

A

T

29
Q

What is optimal length?

A

is the point of optimal overlap of thick-filament cross bridges and thin-filament cross-bridge binding sites before contraction

30
Q

muscles cannot vary beyond 30% of their optimal length. At the outer limits of this range, muscles still can achieve about 50% of their maximal tetanic contraction.

A

T

31
Q 
In the body:
 The resting length of 
a skeletal muscle is
approximately its 
optimal length
A

T

32
Q

In both isotonic and isometric contractions muscle tension is transmitted to bone via the elastic components of muscle

A

T

33
Q

There is a positive correlation between velocity of muscle contraction and load

A

F

The velocity of shortening decreases as the load increases.

34
Q

What are the main differences betwen different types of skeletal muscle fibres?

A
  • Enzymatic pathways for ATP synthesis
  • Resistance to fatigue (greater ATP synthesis greater resistance)
  • Activity of Myosin ATPase
35
Q

Myosin ATPase determines…

A

he speed at which energy is made available for cross bridge cycling i.e. the speed of contraction

36
Q

What are the metabolic pathways that supply ATP to the muscle? (3 ways)

A
  • Transfer of high energy phosphate from creatine phosphate to ADP (immediate!)
  • Oxidative phosphorylation fueled by glucose derived from muscle glycogen stores or by products delivered by the blood
  • Glycolysis (main source when O2 not present) produces pyruvic acid which is converted to lactic acid. Lack of O2 prevents further processing in oxidative phos pathway
37
Q

What are the three types of muscle fibres?

A

Slow oxidative
Fast oxidativ
Fast glycolytic

38
Q

Slow oxidative muscle has - Myosin ATPase activtiy and - speed of contraction. It is - resistant to fatigue and has a - oxidative phosphyrlation capacity

A

Low, Slow, highly, high

39
Q

Fast oxidative muscle has - Myosin ATPase activtiy and - speed of contraction. It is - resistant to fatigue and has a - oxidative phosphyrlation capacity. It uses - metabolism

A

high, fast, intermediately, high

aerobic and anaerobic

40
Q

Fast glcolytic muscle has - Myosin ATPase activtiy and - speed of contraction. It is - resistant to fatigue and has a - oxidative phosphyrlation capacity. It uses - metabolism

A

High, fast, lowly, low, anaerobic

41
Q

Slow oxidative fibres are used mainly for?

A

Prolonged low work aerobic activities e.g. maintenace of posture and walking

42
Q

Fast oxidative fibres are used mainly for?

A

Prolonged relatively moderate work activities e.g. jogging

43
Q

What is a reflex action?

A

stereotyped response to a specific stimulus

44
Q

What is a muscle spindle?

A
  • It is a sensory receptor that is activated by muscle stretch
  • It is made of specialised muscle fibres
  • It has sensory nerve endings known as ANNULOSPIRAL fibres
45
Q

What are the consequences of stimulating a muscle spindle?

A
  1. Increase firing in the afferent neurones
  2. Afferet neurones synapse with ALPHA MOTOR NEURONS (efferent nerves) that innervate the stretched muscle
  3. Contraction of stretched muscle
46
Q

The stretch reflex is coordinated by simultaneous contraction of antagonist muscle

A

F

relaxation of anatognist

47
Q

What are extrafusal and intrafusal fibres?

A

Muscle spindles are intrafusal

Ordinary muscle fibres are extrafusal

48
Q

Where are muscle spindles found?

A

Within the belly of muscle and run parallel to ordinary muscle fibres

49
Q

What is the role of GAMMA nerves in the muscle spindle?

A
  • They are the spindle’s OWN supply of efferent (motor) nerve
  • They adjust the tension in the spindle to maintain the sensitvity when the muscle shortens during contraction
50
Q

The contraction of intrafusal fibres does not contribute to the overall strength of muscle contraction

A

T

51
Q

How can skeletal muscle function be impaired?

A

(1) Intrinsic disease of muscle
(2) Disease of NMJ

(3) Disease of lower motor neurons
which supply the muscle
(4) Disruption of input to motor

52
Q

What are some investigations used in the diagnosis of neuromuscular disease?

A
  • Electromyography
  • Nerve conduction studies
  • Muscle enzymes
  • Inflammatory markers
  • Muscle biopsy
53
Q

What is electromyography?

A

Eelctrodes detect presence of muscular activity - recording frequency and amplitude of APs.

DO NOT PROVIDE DEFINITIVE DIAGNOSIS

Help differentiate primary muscle disease from neurlogical disease

54
Q

What are some causes of intrinsic muscle disease? (4)

A

Inflammatory myopathies e.g. polymyositis, inclusion body myositis
Non-Inflammatory myopathies e.g. fibromyalgia

Endocrine mypoathies e.g. Cushing syndrome, thyroid disease

Toxic myopathies e.g. alcohol, statins

Congenital myopathies: Chronic Degeneration of contractile elements - muscular dystrophy
Abnormalities in muscle membrane ion channels e.g. myotonia

55
Q

What is the difference between a simple and compound synovial joint?

A

Simple - one pair of articular surfaces

Compound- more than one pair of articular surfaces

MSK (8 decks)

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