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Flashcards in Physiology Length-Tension Relationship Deck (23):
0

Length tension relationship

Relationship between the resting length of the muscle at rest before a contraction, and the force developed upon contraction from that resting length

1

Total tension=

Active tension + passive tension

2

Active tension is due to

Crossbridge cycling

3

Passive tension is due to

Series elastic element (SEE)

4

What is happening with crossbridge activity when actin and myosin have less overlap?

There is less crossbridge activity

5

More crossbridges= (more/less) force?

More

6

What trauma is likely to occur when actin and myosin fibers do not have much overlap when muscle contraction begins?

Tearing

7

Stretch insufficiency

Less force development due to muscle being in a stretched position at beginning of contraction

8

Crossbridge polarity

Crossbridges are only able to push in one direction: toward center of sarcomere

9

Muscle shorten weakness

Muscle weakness due to contraction beginning when the sarcomere is shorter than normal

10

Underlying causes of muscle shorten weakness

1 Crossbridges are pushing against each other because actin can't really go anywhere
2 Myosin filaments are impinging which will also mechanically interfere with force development

11

Load

Amount of force developed by the muscle

12

Velocity

Velocity of muscle shortening

13

What is it called when the velocity of shortening is 0?

Isometric

14

What happens as load decreases?

Velocity of muscle shortening increases

15

Why does smooth muscle have its name?

No striations, like skeletal muscle has

16

Does smooth muscle have actin and myosin filaments?

Yes, just not in the arrangement seen in skeletal muscle

17

Does smooth muscle have sarcoplasmic reticulum? Why?

No.
1. Cells are much smaller than muscle cells, so they are able to depend only on the calcium diffusing from outside
2. Smooth muscle is not required to have rapid contraction

18

Does smooth muscle have troponin and tropomyosin?

No

19

Calmodulin

Protein in smooth muscle cells that regulates the contraction

20

Process of muscle contraction in smooth muscle

1. Calcium attaches to calmodulin
2. Calmodulin attaches to inactive myosin light chain kinase (MLCK) on S2 head, activating it
3. MLCK cleaves ATP
4. Crossbridge cycling occurs

21

Study graphs

Load velocity relationship
Length tension curve
Length tension relationship

22

Where does most alcohol absorption occur?

Small intestine