Muscle Pt 5

Question 1

What are the 3 determinates of force/tension within ONE MUSCLE CELL?

Answer 1

1. Fiber diameter (dircetly proportional to tension)
2. Inital fiber length
3. Frequency of activation

Question 2

What are 2 determinates of force/tension in ONE WHOLE MUSCLE

Answer 2

1. # & type of motor units used –> # muscle fibers they link to
2. # of motor units activated

???
1. # of motor units & muscle cells activated
2. type of motor unit activated

Question 3

determinant of force in one muscle cell (fiber diameter )

The amount of tension made is ___ proportional to the # of cross-bridges formed

Answer 3

directly

Question 4

Determinate of force in one muscle cell (initial resting length)

Length-tension relationship of sarcomere refers to . . .

Answer 4

sarcomeres having an optimal length where they produce optimal tension, to much/little overlap (leghth) of thick/thin filaments = decrease in tension

elesatic recoil of skeletal muscle resets optimal resting length

Question 5

determinant of force in one muscle cell (frequency of activation)

force made by a muscle fiber (cell) is increase by __ of multiple _

Answer 5

summation of multiple twitches

Question 6

1 AP in 1 muscle fiber creates = twich. And each single twitch only releases set amount of Ca, therefore it ___ represent the maximal force a muscle fiber can develope

Answer 6

single twitch doesn’t represent maximal force in muscle fiber

AP last 1ms and one twich =100 ms
if you can produce multiple AP (close together in time) before fiber relaxation, then summation occurs to make a greater force

Question 7

The force developed by ONE MUSCLE FIBER can be increased by . . .
The force developed by ONE WHOLE SKELETAL MSUCLE can be increased by . . .

Answer 7

increase in one muscle fiber force = caused by summation of twitches, unfused/fused tetanus
increase in whole skeletal muscle = caused by reqruitment of more motor units

Question 8

What is a motor unit?

Answer 8

one SINGLE motor NUERON & all + muscle fibers connected

One motor nueorn can only connect to similar muscle fiber types

Question 9

What is tension?

Answer 9

the force pulling on the attachment points of a muscle toward one acother –><— ?

Question 10

What are 2 types of muscle contraction?

Answer 10

1. Isotonic contraction
2. Isometric contraction

Question 11

What is isotonic contraction? 2 ex.

Answer 11

any contraction that generates force that moves a load or causes movement (changes in length)
1. eccentric contacrtion = lengthening contractions = IIIII—->x = (the muscle shorten while contracting/generating force)
2. concetric contraction = shortening contractions = IIII <—-x = (the muscle lenghthens while contracting/generating force)

Question 12

What is isometric contraction?

Answer 12

muscle technically contracts = but duesn’t cause change in muscle length = therefore not overcoming/moving load and causing movement

Question 13

T/F Every contractions starts as a isotonic contraction

Answer 13

False = starts off as an isometric contraction

Question 14

How is isometric contraction possible?

Answer 14

muscle has not yet shortened = can happen due to elastic elements that make up of movement changes?