Physiology of Muscle Contraction Flashcards Preview

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Flashcards in Physiology of Muscle Contraction Deck (79)
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1

Sarcomeres end to end make up...

Myofibril

2

Many myofibrils make up the...

Muscle fiber

3

A single motor neuron and all of the muscle fibers it supplies

Motor Unit

4

A single nerve cell

A bundle of neurons

Neuron

Nerve

5

Smallest recordable contraction, a response to a single threshold stimulus large enough to create Action Potential

Muscle Twitch

6

First phase of muscle twitch between the stimulus and initiation of muscle twitch response

Time when excitation is recurring, action potential release of Ca and up to initial binding of myosin head to actin. No tension is generated yet

Latency

7

Phase where power stokes occur, onset of shortening to peak of tension development

Contraction

8

Phase where Ca is taken back into terminal cysternae, ATP comes and and causes cross bridges to let go

Relaxation

9

Does twitch duration vary with muscle fiber type?

Yes

10

Which muscle have a slower twitch? Which ones have a faster?

Posturals have slower twitches
Rapid response muscles have faster twitches

11

Way to increase tension past the muscle twitch

Graded Muscle Response

12

This graded muscle response that increases the rate of stimulus delivery

Temporal Summation

13

What occurs when there is no relaxation from temporal summation, analagous to a charlie horse

Tetany

14

Type of temporal summation that is good for daily activity

Wave Summation

15

Graded muscle response where sequentially more units are recruited as stimulus intensity increases. Results in smooth steady increase in force.

Multiple Motor Unit Summation

16

Are smaller or larger units recruited first?

Smaller (less fiber associated with single nerve cell)

17

Graded muscle response of the warm up effect, with repeated stimuli, muscle warms up and enzymes (myosin ATPase, etc) become more efficient and stronger contraction ensues

Treppe

18

How does treppe differ from temporal summation?

Treppe has COMPLETE relaxtion between stimuli

19

This is the force that is generated by cross bridge formation

Force on object

Weight on object

Contraction

Tension

Load

20

Type of contraction same tension but changing length of muscle

Isotonic contraction

21

Type of isotonic contraction that shortens the muscle, only type explained by Huxley's theory (sarcomere shortening)

Concentric

22

Type of isotonic contraction where the muscle lengthens

Ex: lift heavy weight and place it down on the table. Not explained by Huxley's theory

Eccentric

23

Contraction where the muscle stays same length but force changes.

Ex: Getting up out of chair and push against wall

Isometric

24

Type of contraction that is mechanically induced, performed at same speed with a controlled angular velocity of joint. Doesn't happen in daily life.

Typically on exercise machines

Isokinetic

25

What to type of contractions are performed in daily life?

Isotonic and Isometric contraction

26

Larger muscle means larger force

(DUH)

27

The 4 non-contractile elements of muscle cells that are elastic

Connective tissue covering
Tendons
Organelles
Sarcolemme

28

2 proteins that are non contractile in muscle

Titin and Nebulin

29

Tension in a muscle that is directed at overcoming non contractile element elasticity

Internal

30

In a twitch, most of stimulus is used as...

Internal tension