Lecture 24- Muscle Contraction and Skeletons

Question 1

Thin filaments are composed of____

Answer 1

actin

Question 2

thick filaments are composed of ___

Answer 2

staggered arrays of myosin

Question 3

muscle contraction relies on the interaction between ____

Answer 3

thick and thin filaments

Question 4

Skeletal muscle consists of

Answer 4

a bundle of long fibers, each a single cell, running along the length of the muscle

Question 5

Each muscle fiber is ____

Answer 5

a bundle of smaller myofibrils arranged longitudinally

Question 6

How do muscles contract?

Answer 6

thin and thick filaments ratchet past each other longitudinally, powered by the myosin molecules

Question 7

Steps to muscle contraction

Answer 7

1. ATP binds to myosin head
2. ATP hydrolyzed
3. Pi released
4. ADP released

Question 8

Step 1: ATP binds to myosin head

Answer 8

The myosin head releases from the thin filament

Question 9

Step 2: ATP hydrolyzed

Answer 9

the head pivots and binds to the new actin subunit

Question 10

Step 3: Pi Released

Answer 10

Head pivots, moving the thin filament (power stroke)

Question 11

Step 4: ADP released

Answer 11

cycle repeats

Question 12

Varying the number of fibers that contract can impact the ______

Answer 12

strength of contraction

Question 13

A motor unit consists of ____

Answer 13

• single motor neuron
• all the muscle fibers it controls

Question 14

Recruitment process

Answer 14

the process by which more and more motor neurons are activated

Question 15

How does the nervous system regulate muscle contraction?

Answer 15

varying the rate of muscle fiber stimulation

Question 16

Tetanus

Answer 16

state of smooth and sustained contraction produced

Question 17

Skeletal systems transform muscle contraction into ____

Answer 17

locomotion

Question 18

Types of skeletons

Answer 18

• Exoskeleton
• Endoskeleton
• Hydrostatic

Question 19

Exoskeleton

Answer 19

The hard structure is on the outside of the organism with soft tissue inside

Question 20

Endoskeleton

Answer 20

the hard structure is on the inside of the organism surrounded by soft tissue

Question 21

Skeletal muscles are attached in _____ pairs

Answer 21

antagonistic

Question 22

Hydrostatic skeletons

Answer 22

muscle change shape of the fluid filled compartments to facilitate movement