Human Phys 2.7 Flashcards

1
Q

Length tension relationship

A

Amount of tension developed changes according to the length of the sarcomere

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

Length tension relationship step by step

A
  1. Actin pulled all the way out with no cross bridge overlap (no tension)
  2. 2.2 micrometers long, cross bridge overlap occurs (thick filament is free providing room for sliding) (optimal length for sarcomere)
  3. 2 micrometers long, constant tension, ends of actin begin to touch and overlap (optimal length for sarcomere)
  4. 1.65 micrometers long, strength of contraction drops, Z discs abut ends of thick filament (myosin heads are not fitting well in binding sites)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why would the end of contraction go up rather than down on a length tension relationship?

A

Due to passive tension

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

What is passive tension produced by?

A

Cytoskeleton and other connective tissue

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

When does the passive component come into play?

A

Only at longer lengths

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

Force velocity relationship

A

The bigger the load the slower the velocity (power)

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

What is the speed of the contraction determined by?

A

Vmax of myosin ATPase

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

High Vmax (fast, white)

A

Rapid cross bridge cycling

Rapid rate of shortening

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

Low Vmax (slow, red)

A

Slow cross bridge cycling

Slow rate of shortening

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

What do most muscle fibers contain?

A

Both fast and slow fibers but proportions will differ

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

What will all fibers in a particular motor unit be?

A

The same type of fiber

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

Slow twitch fiber (1)

A

Oxidative (resistant to fatigue)

Small diameter

High myoglobin content

High capillary density

Many mitochondria

Low glycolytic enzyme content

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

Fast fibers (2)

A

Glycolytic (fatigue quickly)

Low myoglobin content

Low capillary density

Few mitochondria

High glycolytic enzyme content

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

Motor unit

A

Anterior horn cell, nerve fiber, and all the muscle fibers it innervates

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

Small motor units

A

10 fibers

Precise control

Rapid reacting

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

Large motor units

A

1000 fibers

Coarse control

Slower reacting

17
Q

Motor units overlap, what does this provide?

A

Coordination

18
Q

Size principle

A

Smaller motor units will be stimulated before larger ones