Brainscape's Knowledge GenomeTM

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


See full index

Kin 2241: Biomechanics > Lecture 6: Neuromuscular Aspects of Movement I > Flashcards

Lecture 6: Neuromuscular Aspects of Movement I Flashcards

1
Q

Muscles and motion

A

Muscles produce a motion when it creates tension and tries to shorten

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

Skeletal muscle

A
  • overlap over each other
  • striated (tells which way it will pull)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Origin

A

Proximal attachment of a muscle
- closer to axial skeleton

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

Distal

A

Distal attachment of a muscle

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

Wrapping points/retinacula

A

redirect muscle pull btwn origin and insertion

Wrapping points change direction (can be negative or positive)

Negative angle is held down by retinacula

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

Aponeuroses

A

Wide bands of connective tissue (wide tendon)

Attach muscle to bones like tendons

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

Layers of muscle

A

myofirbils (smallest unit) –> muscle fibres –> fascicle –> muscle (biggest)

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

Endomysium

A

covers muscle fibres

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

Fascicles

A

bundles of muscle fibres

covered by perimysium

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

Perimysium

A

covers fascicles

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

Epimysium

A

covers whole muscle AND tendon
- like cling flim

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

Sarcomere

A

Smallest contractile unit of muscle
- connected together in series
- Z-disc to Z-disc
Has actin and myosin

When stimulated by motor nerve, the sarcomere shortens

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

Actin

A

thin filament

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

Myosin

A

thick filament

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

Muscle contraction

A

Z-Discs get closer and I-band gets narrower
- A-band does NOT change

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

Light/dark bands and muscle

A

Myosin (thick) = dark band (absorbs lots of light)

Light bands - I band
Dark bands - A band

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

Rigor mortis

A

NO ATP
- can’t hydrolyze to form ADP and disconnect crossbridges

Small muscles go into rigor first and big muscles last (big muscles have higher ATP stores)

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

Length-tension curve

A

Best scenario (2): 2.20-2.25 microns
- produces 100% of tension (ideal)

worst case (1): longest sarcomere (no actin for crossbridges to connect) = no contraction

1 (longest) –> 6 (shortest)

shortest sarcomere = overlap in actin = decrease in tension

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

Pennation angle

A

Angle btwn muscle fibres and the line of pull of the muscle

Smaller angle = more direct pull = LESS force and more excursion
- fatigues easily

Larger angle = less direct pull = greater force and smaller excursion (small movement)
- force multiplier = can put more muscle fibres in parallel

20
Q

Small pennation

A

Large excursion, small force, easily fatigued, quick rxn. time

Ex. Tibialis anterior (small angle)
- only needed for dorsiflexion when walking (small excursion)

Fusiform muscle

21
Q

Fusiform muscle

A

Little to no pennation angle

22
Q

Large pennation

A

Small excursion, large force (can stack more in parallel), goof endurance, slower rxn. time

Ex. Gastrocnemius

23
Q

Pennation arrangements

A

Longitudinal
Unipennate
Bipennate
Multipennate

24
Q

Longitudinal pennation

A

Fusiform muscle
- little to no pennation angle

Muscle fibres travel in direction of muscle pull

Ex. sartorius and tib ant.

25
Q

Unipennate

A

single pennation angle btwn muscle fibres and direction of pull

pulls in one direction

more likely to see aponeuroses

26
Q

Bipennate

A

pulls equally both ways

tracks to one side b/c there are 2 slightly different pennation angles

Ex. vastus intermedius

27
Q

Multipennate

A

pulls in multiple directions

jack of many trades, master of none
- likely to pull or tear b/c it doesn’t do any one thing well

Ex. rotator cuff

28
Q

CHARACTERISTICS OF A MUSCLE

A
  1. Flexibility: how much ROM does the muscle allow at the jt
  2. Strength: maximum FORCE that can be created
  3. Power: how FAST can the muscle produce force (force x velocity)
    - explosive starts
  4. Endurance: how LONG can the muscle produce force?
    - fusiform muscles tire out quickly
29
Q

Knee extensor group

A

Quads (anterior)
- vastus lateralis
- vastus intermedius
- vastus medialis
- rectus femoris (also a hip flexor)

30
Q

Elbow flexor group

A

Anterior

  • biceps brachii
  • brachialis
  • brachioradialis

Brachialis and brachioradialis fill in ROM to allow usable power when biceps are too short/long

31
Q

Uniarticulate muscle

A

One-joint muscle

only cross one joint = only affect one joint when they contract

Ex. soleus in calf group (only crosses ankle)

32
Q

Multiarticulate muscles

A

Multi-joint muscles

Cross two or more joints = affect several jts SIMULTANEOUSLY when they contract

Ex. gastrocenemius in calf (crosses ankle and knee)

33
Q

Drawback of multi-joint muscles

A

They can’t get full ROM at both joints simultaneously

Active and passive insufficiency

Ex. semimembranosus and semitendinosus are vulnerable b/c they cross hip and knee
- both thrown into passive insufficiency = too long = tear

34
Q

Active insufficiency

A

muscle CAN’T SHORTEN enough

too short = active part in making it too short (you do action)

35
Q

Passive insufficiency

A

muscle CAN’T LENGTHEN enough

36
Q

Steps of movement

A
  1. Agonist starts moving
  2. Antagonist stops moving
  3. Co-contraction (slow and fix mistakes)
37
Q

Agonists

A

Muscles that pull together to produce the DESIRED motion at a joint

Ex. trying to lift a glass of water to mouth: elbow flexors are agonists

38
Q

Antagonists

A

Muscles that pull in OPPOSITE DIRECTION at a joint

Ex. elbow extensors

39
Q

Agonist-antagonist relationship

A

When agonists are active, antagonist group is inhibited to allow motion

In some situations, there is CO-CONTRACTION (both groups are active)
- used to stabilize of slow the jt.

40
Q

What happens when a muscle is activated by a motor nerve?

A

The sarcomeres ATTEMPT to shorten (not always able to)

41
Q

Concentric contraction

A

Muscle is activated and SHORTENS

External loading is insufficient

42
Q

Isometric contraction

A

Muscle is activated and REMAINS THE SAME LENGTH

External loading exactly balances internal force produced by muscle

Ex. planks, holding yoga pose

43
Q

Eccentric contraction

A

Muscle is activated and LENGTHENES

Produces more force than other ways

44
Q

FACTORS THAT DETERMINE AMOUNT OF TENSION FROM MUSCLE ACTIVATION

A
  1. The AMOUNT of activation (does the brain want full or partial power)
  2. LENGTH of muscle (muscle has an ‘ideal length’ for max tension. Tension drops off if longer or shorter)
  3. SPEED of muscle (as muscle shortens faster, its tension drops quickly)
    - lengthening muscle (eccentric) = tension goes up
45
Q

Velocity-Tension Curve

A

Power is a parabolic function

In concentric phase, force drops off exponentially as velocity increases (force stays below 1)

At isometric contraction, force is at 1

At eccentric contraction, force goes above 1 then plateaus at max
- some fusiform muscles can go up to 180% with external load
- external load is needed to lengthen

46
Q

Velocity and force

A

Inverse relationship

As velocity increases, force decreases

Kin 2241: Biomechanics (15 decks)

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